??ifki£* TREATISE SPECIAL AID GENERAL ANATOMY. BY WILLIAM E. HORNER, M. D. PROFESSOR. OF ANATOMY IK THE ONIVERSITY OF PENNSYLVAlljk—MEMBER OF THE IMPERIAL MEDICO-CHIRURGICAL ACADEMY OF.ST. PETERSBURG—OF THE AMERICAN PHILOSOPHICAL SOCIETvL&C. Multum adhuc restat operis, multumque restabit, nee uUi nato, posj mille sjecula pnecluditur occasio aliquid adjiciendi. SENECA, EPIST. IN TWO VOLUMES. 1 VOL.. I. .\ FOURTH EDITION, REVISED AND IMPROVED »fctiaielpfttet" CAREY, LEA & BLANCHARD, 1836. rUlfef \<334 v, 1 Eastern District of Pennsylvania, to wit: BE IT REMEMBERED, that, on the seventeenth day of October, iff the fifty-first year of the Independence of the United States of America, A. D*. 1826, Wiixiam E. Homier, of the said district, hath deposited in this office the title of a book, the right whereof he claims as Author, in the words follow^ ing, to wit:— " A Treatise on Special and General Anatomy. By William E. Horner, M. D.„ Adjunct Professor of Anatomy in the University of Pennsylvania—"Member of the American Philosophical Society-!-Surgeon at the Philadelphia Alms House, &c. ' Multum adhuc restat operis, multumque restabit, nee uUi nato, post mille saecula pracludilur occasio aliquid adjiciendi.' Seneca, Epist. In Two volumes. Vol. I." In conformity to the Act of the Congress of the United States, entitled, " Are Act for the Encouragement of Learning, by securing the Copies of Maps, Charts, and Books, to the Authors and Proprietors of such Copies, during the times therein mentioned"—And also to the Act, entitled, "An Act supplemen- tary to an Act, entitled, 'An Act for the Encouragement of Learning, by se- curing the Copies of Maps, Charts, and Books, to the Authors and Proprietors of such Copies, during the times therein mentioned,' and extending the bene- fits thereof to the arts of designing, engraving, and etching Historical and other Prints." D. CALDWELL, Clerk of the Eastern District of Pennsylvania. PREFACE. The many additions that, of late years, have been made to Descriptive or Special Anatomy; the improved views on the collocation of its objects; the alterations and amendments in the method of description; and the now urgent call for some greater information on General Ana- tomy than what is commonly introduced into the scho- lastic systems; require in the English language, for the benefit of the medical student and of the practitioner, a new work on the structure of the body, executed by one who is in the habit of pursuing anatomical inquiries by constant dissection. It would have been pleasant to me if some gentleman, whose time, opportunities, qualifica- tions, and spirit of research were better suited to the en- terprise, had stepped forward for its accomplishment. While meditating on this subject, I had a strong desire to remodel the excellent work of Dr. Wistar,* on a plan more suited to the actual state of the science; but, upon reflecting that it was a justly celebrated monument to his reputation, I became dissatisfied with the project of cutting and carving it into a more modern figure. In addition to which consideration, having frequently de- * A System of Anatomy for the use of Students of Medicine.— Philadelphia, I81T. IV PREFACE. parted from his authority, the alternative was presented either of suppressing his ideas to substitute my own, or of giving currency to opinions differing from my own convictions, neither of which was agreeable. The la- bour, moreover, of remodelling, would have been almost equal to the writing of a new book. Neither is there any work extant from the British press, which presents a good model for a body of Ana- tomy. This assertion may surprise some, and yet it is entirely true, and especially so in regard to the British publications most circulated in this country: I allude to the Anatomy of Mr. Fyfe,* and to that of Mr. Bell.f The first, from being unpretending, good in its way, and having accomplished the object for which ' it was intended; to wit, as a general outline of anatomi- cal objects, requires for the present no farther comment. But the second, being presented to us in the imposing' form of four octavo volumes; illustrated by numerous dia- grams and plates; abounding in strictures upon the opi- nions of others, and written in a fanciful pleasant man- ner; has had a much more powerful influence on the taste of the American student, and is, therefore, a very pro- per subject for a short analysis. It is not going beyond bounds, when I say, that there is no work which affords more amusement to the young student on the first peru- sal, or whose authority is viewed by him with more de- ference. Its sprightly style; its confident maimer of * A Compendium of the Anatomy of the Human Body, intended principally for the use of Students. Philad. Ed. 1802. f The Anatomy of the Human Body, illustrated with one hundred and twenty-six engravings. By John Bell, Surgeon. PREFACE. V address; the many exploded, antiquated errors which have been disentombed from absolute oblivion, in order to make the reader laugh at them; the grotesque dress put upon the valuable opinions of others; and their tra- vestied doctrines; all contribute to make it read like a production of the imagination, and to have the same sort of popularity which works of the latter kind frequently enjoy. As the real importance, however, of a work upon an exact science does not exist in its wit and " bi- zarreries," but upon the wholesomeness of its truths, and the accuracy with which they are stated; it is fair to expect that the writer should himself be faultless, who thus uses the weakness of others as the foil upon which to display, most advantageously, his own presumed bril- liancy and perfection. It does not require much scru- tiny to ascertain whether the expectation is realized, and whether this author does not abound in inaccuracies, in exaggeration, in obscurities, and in irrelative matter. In regard to the inaccuracies of Mr. Bell, we give the following as specimens, which we have got without far- ther trouble than that of thumbing his pages. "This membrane (the Mediastinum) passes directly across the breast from the sternum before, till it fixes itself in the spine behind. It is on the left side of this membrane, in the left cavity of the breast, that the heart is placed." " The Eustachian Valve is in general thick and fleshy." " The Pericardium is formed, like the Pleura and Me- diastinum, of the cellular substance." " The Perioste- um is merely a condensation of the common cellular sub- stance, formed in successive layers." " The perioste- um, tendons, fasciae and bursse mucosae, are all of one VI PREFACE. substance and of one common nature." "The socket, (i. e. the acetabulum) is deepened by its cartilage, which tips the edge of the socket, and stands up to a considera- ble height." Some of these mistakes are glaring blun- ders; others may perhaps be referred to the faulty phra- seology of the author, from his imperfect notions of the elementary tissues of the body; but their mischievous ef- fect is the same. Whatever may be the surprise of the student in seeing a popular author thus commit himself, it will be increased to astonishment by an example or two from his Principles of Surgery.* "The tendon of the rectus also takes its origin from the fore part of the cap- sule,! and the capsule is at that part singularly thick; indeed, it is hardly at any part of its circumference less than half an inch in thickness, and is of a gristly hard- ness." u A poor man, who was by trade a leech catch- er, fell as he was stepping out of a boat, and the long and pointed scissors which are used in his business, being in his pocket, pierced his hip, exactly over the place of the sciatic notch, where the great iliac artery comes out from the pelvis." One might suppose in reading these passages, that some peculiarities of structure, from ha- bits of life, had been manifested in the subjects submit- ted to Mr. Bell's knife; but in that case we should have heard of such from other sources also; and as we have in this city extensive and varied opportunities of dis- secting, we ourselves must have noticed them; moreover, it is entirely unknown for modes of life to alter the course of the arteries, and to bring out the Great Iliac (Primi- * London, 1815. t Of the hip joint. PREFACE. Vli tive Iliac) at the sciatic notch, instead of its being con- fined to the usual course and boundaries. Another circumstance to be noted in Mr. Bell, is the extraordinary proceedings and modes of operating to which his patients were subjected. The same unfortu- nate leech catcher, with such an unusual distribution of the great iliac artery, had his miseries increased by the formation of a "prodigious aneurism" at the part in- jured; " upon opening the tumour fully with an incision eight inches long, and turning out the great clots, the blood was thrown out with a whishing noise, and with such impetus, that the assistants were covered with it, and in a moment twenty hands were about the tumour, and the bag (aneurism) was filled with sponges, and cloths of all kinds, they were insufficient to arrest the bleeding. Seeing, at this critical moment, that if he was to be saved it was to be only by a sudden stroke, I ran the bistoury upwards and downwards, and at once made my incision, two foot in length." This tale bears with it a hyperbolical, romantic character, and if Mr. Bell had also said, that he and the ten assistants had been floated to the other side of the " operation room " in the grand sluice of blood which followed the opening of the tumour, we should have considered the swim as only an addition to the figurative and oriental style, in which his ideas are generally conveyed. But he checks this indulgence to his manner, by a previous admonition for the reader not to think that he exaggerates the difficul- ties of such operations. The irrelative and exploded matter which Mr. Bell has introduced into his anatomy, is not the least re- viii PREFACE. markable of its characters. Thus, he tells of the opinion of Hippocrates, that the water of the pericardium is the drink that we swallow.—Of the dispute between Bardi- us and Bartholin about the source of the water that flowed from our Saviour's side, on the occasion of his being pierced by the spear.—Of the theory of Des Cartes, of , one portion of blood in the heart acting upon another, like vitriol upon tartar, and thereby ejecting itself through the aorta.—Of side passages in the heart through the septum of the ventricles.—Of the celebrated gene- ral of the Messenians, Aristomenes, known equally well for his devotion and constancy to the cause of his coun- trymen, having his heart filled with hair, a proof of his invincible courage and daring.—Of the eel which was found in the heart of a patient of Dr. May. These mat- ters may possibly be excused on the footing of episodes, intended to diminish the tediousness of a long story. The oddities of this writer are likewise entirely cha- racteristic : thus, we have in his Principles of Surgery a regular diagram of the resemblance between the thigh bone and a chariot with dished wheels. "Polonius. Very like a whale." The last comment which we have to make touching this "popular writer" is on his anatomical illustrations. I cannot enter into an analysis of them, but have only time to say, that if ever a simple matter was perplexed by illustrations, we have this feat to perfection in the ac- count of the Circulation, of Respiration, and of the round of blood in the Foetus.* * The preceding observations are principally applicable to the first and second volumes of the Anatomy of the Human Body; the PREFACE. ix The character of the preceding vagaries may suit a writer on common literary subjects, where amusement only is intended; but is totally unfitted to an instructor in an exact science, where words should be used only according to their technical meaning, and where patient observation is the only guarantee from ridiculous mis- takes. But I must here stop, for I have never aspired to the reputation of a critic, and to the equivocal friend- ship with the rest of the world which such commentators generally have. I have only been induced to point out these faults, because it appeared to me that the writer alluded to, though now numbered with the dead, has left a reputation tending to deprave the scientific ha- bits of such medical students, and they,'I believe, are not a few, as read his works. I am also checked by the hint of Le Sage: "En verite sil y a bien de mauvais au- teurs, il faut convenir q'il y a encore plus de mauvais critiques."* I, therefore, conclude by suggesting, that if an exact science require for the relief of its student some dilution with the works of the imagination; instead of corrupting it with mere notions and exaggerations, it would be much better for the student to resort to pro- ductions of the first merit, and to hold in one hand his System of Anatomy, and in the other a Milton, or a Wa- verley Novel. third and fourth have been executed in much better taste by Mr. Charles Bell. * In truth, if there are many wretched authors, one must con- fess that there are many more wretched critics.—Gil Bias. Vol. L—2 X PREFACE. I should be extremely sorry to be understood as doubt- ing the capability of the British anatomists to write a good treatise on this subject. I indeed feel persuaded of the contrary; and, therefore, only mean that as yet they have not, in this particular, done justice to them- selves, or to the literary reputation of their country. Any other opinion would be great injustice to them, and would also be ingratitude for acts of friendship and civi- lity received from many illustrious and enlightened indi- viduals whom the profession is proud to own; and alle- giance to whose doctrines has, moreover, been freely avowed, in the present work, on proper occasions. To the profound anatomist, whose inclinations lead him to study every fasciculus of fibres composing a muscle or a ligament, and every minute nervous or arterial ramifi- cation, the present Treatise on Anatomy will, of course, be a mere outline of the science. But to the student of medicine and to the practitioner, who have only time to dwell upon prominent and useful points, I trust that it will appear sufficiently full for most professional objects. The anatomy of the human body is of an extent much beyond the common conceptions of it, and is rather a ge- neric then a specific term. A full treatise on it would contain matter to twice or three times the extent of the present work, and would even then be in many respects deficient; for it must not only give a full description of parts in the adult body, but their first appearance in foetal life, and their gradual devolopment into the perfect or adult state. It must also contain a complete account of the properties of each kind of structure composing the human body, called, in technical language, General Ana- PREFACE. Xi tomy; also morbid alterations of structure, and finally va- rieties in shape, position, &c. It is here proper to remark, that though every human body be formed on the same general mould, yet, in exa- mining the details of structure in an individual, varieties will be met with causing a difference from all other indi- viduals. For as no two leaves or two human counte- nances are precisely alike, so the interior organs of indi- viduals differ in their phases, thougli the same end is ob- tained. Hence it becomes necessary for a system of ana- tomy to show rather what is of the most frequent occur- rence, than to pretend to universal correctness; because, by the latter test, many of its accounts are inexact. Some of these departures from the general rule are so in- frequent as to deserve the name of anomalies: in some cases, there are, indeed, only one or two recorded in- stances; but, in others, the variation is so frequent as to leave the anatomist in doubt, about what mode of descrip- tion is applicable to the majority of cases. From this latter cause, we, in consulting different writers, some- times find their opinions much opposed; and to our sur- prise, the adage of quot homines tot sententias, as applica- ble to the science of anatomy, as it is to one of an abstract and confessedly disputable kind. Anatomy, however, in its great outlines, is a science surprisingly and, sufficiently exact; the exceptions are too few to admit of hesitation about what is right and what wrong: it is, therefore, per- haps, next to mathematics in the precision of its indica- tions, and in the value and certainty of its rules. It is, for these reasons, in every way suitable, that in an opera- tion, or in the treatment of a disease, whjere the condition Xll PREFACE. of organs is to be considered; that we should look with fu" assurance for what is most common, rather than to hesitate and vibrate between two opinions; to balk about mere varieties. Otherwise, a knowledge of the possibility of the latter will rather injure than assist our exertions, and our inefficiency will have the appearance and effect of ignorance. Sensible of the importance of reflecting upon, and of observing maturely the matters treated of, I have done my best to be accurately informed by repeated dissec- tions, and by reference to the highest authorities. The latter was happily put into my power, by the well-fur- nished library of the Alms House and of the Pennsylva- nia Hospital; and by a private collection, containing many of the most approved productions. This balancing of the opinions of others with one's own dissections, is un- questionably, best suited to correct inferences: to follow exclusively the one or the other, is attended with great liability to error. An undue deference to approved au- thorities makes our opinions habitually wavering and un- certain, from the discrepance of writers among them- selves; while an insufficient attention to such means of in- formation produces very serious mistakes in correctness of description, and very false ideas of scientific acquire- ments. If we presume on our own infallibility and ori- ginality, we are apt to suppose ourselves possessed of surpassing skill, as floating triumphantly on an ocean of discovery, as extending in every direction the bounda- ries of the science and giving a new impulse to it; while on the contrary, our faulty modes of examination, and ne- glect of competent writers, have caused us to flounder PREFACE. Xiil ridiculously on common-place and well settled points. It is thus that imaginary originality is not unfrequently in an inverse proportion to the recentness-of one's induc- tion into the science, and to the exactness with which it has been studied. In the absence of knowledge, the young and enthusi- astic, but heedless anatomist, is frequently prolific, from the commencement, in discoveries: he makes them in such numbers, with such facility, and under such un- premeditated circumstances, that he is filled with ad- miration at his own^bilities in such matters, and at the ignorance and inattention of his predecessors and co- temporaries. In the ready communication of the result of his labours, he is disposed to use the language of high attainment and of advanced reputation. He hints at his anticipations of the jealousy and malice which are known to follow greatness and excellence; not considering that there is quite as much proneness in an individual to over- rate himself from self-love, as there is in others to decry him unjustly. He feels mortified at the supposed apathy of some persons, and indignant at others for not placing him at once on the pinnacle of fame. After waiting in vain for such homage, he, at length, finds out that the matters treated of have all the triteness of being very well known; or, if they be novelties, they are the off- spring of hasty and imperfect observation, and were rather leading into error than conducting to the truth. An inattention to the writings of others has also the in- convenience of exposing us justly to the raillery and criticism of persons, who, not reflecting that it is scarce- ly possible to bring new truths into vogue, much less er- XIV PREFACE. rors, and that such mistakes carry with them their own seal of death, drag them to the block, there to die by the hand of the public executioner. Dr. W. Hunter* has justly remarked, that "He that is in a hurry to publish his discoveries, will often have occasion to re- pent his haste. Reflection, and more favourable oppor- tunities of making inquiries, will at length bring us back to the truth, if we have been misled, and will con- firm and improve our inventions, if they be right/' The preceding observations are not intended to re- press the spirit of generous enterprise, but rather to as- sist it, by giving it a proper direction. There are, un- questionably, many things yet to be discovered in ana- tomy, as proved by the continued contributions of its cultivators. For, in the language of the motto, "Mul- tum adhuc restat operis, multumque restabit, nee ulli nato, post mille ssecula prsecluditur occasio aliquid ad- jiciendi." These remarks are only intended as a salu- tary warning to the young votary of anatomy, not rashly to promulgate, by boastful writing or language, that he considers his own acquisitions as the standard of the science, and every thing beyond them as in the region of discovery. Because, if he does, he is sure to meet with the most mortifying convictions to the contrarv; and sometimes to find himself placed below the decree of his actual acquirements, for manifesting a want of ac- quaintance with topics common to others. The rule is undoubtedly a good one: "Let not him that put- teth on his harness boast himself, as he that putteth it off." * Med. Comment, p. 57. Lond. 1777. PREFACE. XV Not thinking that the present treatise is a proper field for discussion on controverted points, I have pur- posely, excepting on a few occasions, avoided it, by simply giving an opinion after my own views of correct- ness, without pretending to infallibility, or being dis- posed to reject better information when offered. I can- not, however, but feel the strongest diffidence of my powers to execute, in a moderately satisfactory, not to say a proper manner, the enterprise of writing a treatise on anatomy. There are not many persons, who, as they advance in the study of the science, by dissections and by reading, do not, after awhile, as in the cultivation of high religious and moral attainments, mistrust their ac- quirements; and find, that, whatever may have been the fancied perfection of their knowledge during the infancy of their studies, they were then only on the threshold of the temple. In beginning the career of anatomical inquiries, as an almost exclusive profession, we have yet to appreciate the labours; I may, indeed, say to read the writings of the eminent men who have gone before us. We have yet to learn the immense multitude of ob- servations by which we are surrounded, and the great labour that it requires to master them all. The fact is well established, that it requires some years of hard study before the anatomist becomes aware of his own weakness, and of the many things that he has yet to do in order to be brought up to the actual state of the science. Impressed by these convictions, I have constantly endeavoured to ascertain and present the science of De- scriptive or Special Anatomy, as it stands at the present XVi PREFACE. day,rwithout entering into all the minutiae of details of which it is susceptible. I have, therefore, neglected no fact bearing on the subject, which seemed to be suf- ficiently authenticated or important to deserve notice. Owing, however, to the expanded field in which I have worked, and the many pressing engagements which drew my attention from it, it is not improbable that I may have omitted some things worthy of remark, which I may have subsequent reason to repent my neglect of. By far the greater part of this work has been wrought up in regular manuscript; on several occasions, however, not wishing to make the text more prolix, I have incor- porated with it literal extracts from my " Lessons in Practical Anatomy." This is especially the case in re- gard to the nerves of the extremities and to the muscles. The two works harmonize; yet some unimportant differ- ences may, in a few places, be observed by the attentive reader, owing to improved views in the present. Simple typographical mistakes have also given rise to discre- pancies; but it is almost impossible to avoid a contin- gency of this kind, owing, sometimes, to the inevitable hurry in which a proof-sheet is corrected, and, at others, to the mechanical derangements, to which the press is subject. The great deficiency of the English language in terms suited to anatomical description and nomenclature, and the difficulty of forming suitable compound words from it, have induced me to take some liberties which I would gladly have dispensed with, under other circumstances. To avoid periphrasis, and the inconvenient repetition of sentences, I have, therefore, frequently adopted French PREFACE. xvii V terminations, and sometimes formed a word upon a Greek, a Latin, or a French root; following, in these respects, the authority of the Continental Anatomists. But it is still a great desideratum, for anatomy to be rather more algebraical in its characters and language, than it is at present. Vol. I.—3 INTRODUCTION. The Science of Anatomy has, of late years, been di- vided into Descriptive and General. This distinction, though faintly traced by preceding anatomists, owes its present prominence to the labours of the celebrated Bi- chat; and the daily observations of physiologists and pa- thologists, are only renewed and concurrent evidences of its importance and value in the practice of medicine. Although the distinction is only coming into vogue in this country, the tendency to it is so great that in a few years more, medical language and ideas will be univer- sally tinged with it; it is proper, therefore, that it should be defined in such a manner, that it may be perfectly intelligible to the student. Descriptive Anatomy teaches the exterior form of or- gans, their magnitude, their position, their connexions with adjacent parts; and their intimate texture or or- ganization. As in this way every individual part is brought under a strict review, it is this division of the science which gives skill to the surgeon. The term is not entirely appropriate, because description means any account whatever; the substitution of the phrase Special Anatomy is, therefore, one of the improvements of the present day, and is very much resorted to. General Anatomy may be explained, as its great founder, Bichat, himself has done it, by the following XX INTRODUCTION. comparison. Chemistry has its simple bodies, as heat, light, hydrogen, oxygen, nitrogen, carbon, and so on, whose several combinations form all the composite bodies on the face of the globe. In the same way anatomy has its simple tissues, whose varied combinations form all the organs of the human body and of animals. These tissues 1. The Cellular, - - - Vol. I. p. 317 2. The Adipose, or Medullary, - - 325 3. Vascular, - - - - II. p. 151,281 4. Nervous, ------ 315 5. Osseous,.....I. p. 55 6. Fibrous, or Desmoid, - - - 257 7. Cartilaginous, - - - - ,- 251 8.'The Fibrocartilaginous, - - - 256 9. Muscular,......351 lo. Erectile, or Spongy, as Penis, &c. II. p. 86 11. Mucous,......48 12. Serous, ------ io 13. Dermoid, or Skin, I. p. 329 14. Glandular, as Liver, Kidneys, &c. &c. II. p. 54 The distinctions of tissue do not rest upon an imaginary basis, but have nature for their foundation. The or- ganization of each has well marked and characteristic * Bichat admits twenty-one elementary tissues, but several of them are but modifications of one and the same. For example, the arte- rial, the venous, and the absorbent, belong all to the vascular, and I have thought it useful to concentrate them under one head; and so of some others, where the analogy is equally evident. As the na- ture of the work did not admit of the consecutive description of these tissues, reference is made to the pages in which they are discussed. With this guide they may be studied in immediate succession, by the person desirous of an outline of General Anatomy. INTRODUCTION. xxi peculiarities, which may be ascertained by their diseases, and by the influence of different agents, as heat, air, water, acids, alkalis, neutral salts, and putrefaction. Each tissue has its particular strength, and its particular mode of sensibility, upon which repose all its vital phe- nomena, and the blood is but a common reservoir, where each chooses what is in relation to itself. An example, however, will serve better for illustrating these several points. The stomach is composed of four laminae, one is serous, another muscular, a third cellular, and a fourth mucous. Each of these laminae has its appropriate sen- sibilities and mode of life, which may cause it to be dis- eased, while all the others are healthy. Peritoneal in- flammation may invade the first, the cramps of colic the second or muscular, the infiltration of dropsy the third or cellular, and dyspepsia the fourth or mucous. It thus happens, that the diversity of the tissue of an affected organ modifies the symptoms of its diseases, and especially their duration. Hence, nothing is more vague in medicine, in regard to duration, than the terms chronic and acute. An inflammation in one tissue will go na- turally through its stages in a few days, as, for example, in the skin, cellular substance, mucous membranes; while in the bones and ligaments, on a natural progress being also observed, weeks and months are required for its ac- complishment. It is evident, therefore, that a time which is chronic in the first three tissues, is acute in the last two. A chemical analysis of the body demonstrates only a few elementary principles; and they are varied in their combinations by a greater or less proportion of one or the other. Calcarious matter, the neutral salts, carbon, hydrogen, oxygen, nitrogen, sulphur, iron, wrought up by the powers of animalization into gelatine, albumen, and fibrine, which again are elaborated into the fibrous Xxii INTRODUCTION. and laminated tissue, constitute about the sum total of the results of the experiments of animal chemistry. It has yet to find out the laws of the phenomena which give to these elementary atoms the condition of blood, and afterwards change this blood into muscles, nerves, and other things. The whole body is formed of solids and of fluids. The former, when unravelled, consist of fibres, of laminae, and of molecules; their mechanical division does not admit of any greater separation. Many of the laminae are ar- ranged into membranes, thus forming hollow viscera, for containing either articles of food or the excretions; others surround the different solid viscera and separate them from the contiguous parts. Other laminae penetrate through the most compact structure, and indeed form the nidus in which its atoms or particles are deposited. Many of these laminae consist of several thinner laminae, placed together and united by filaments arranged into cells, which cells receive the ultimate particles of the whole fabric, and constitute its base. The laminae also, by being wrought into cylinders, constitute vessels of different kinds, which are distributed in such numbers through the body, that by far the greater part of its structure seems to be formed of them. In regard to the fluids, they are extremely abundant in number and in quantity, and are found in the cells of the laminated tissue, and in the several vessels. One not accustomed to the process would be astonished to see, when these fluids evaporate by exposure to the air, that nearly all parts of the body, except the skeleton, lose from one- half to two-thirds of their original bulk, and some parts even more. The several solid parts of the body are then literally kept soaked during life in the fluids; which have for a principal constituent, simply water. INTRODUCTION. xxiii There are some animals whose organization is so sim- ple that they possess only the power of sensation; and of motion in one part upon another. This is perhaps the lowest degree in which animal life does exist, or possibly can exist, without a new order of things. These quali- ties, sensation and motion, are of necessity combined al- ways; they constitute the first ingredients in the compo- sition of life, both in vegetables and animals, and by be- ing modified in various ways by their application to dif- ferent organs, may be traced up to the perfect animal, man. Nutrition is the first want of every being, and is one of the modes of sensation; therefore, before any other ap- paratus is provided for animal life, means are resorted to, to carry it on. Vegetables are fixed to the soil, and are furnished with great numbers of porous roots, which by spreading in different directions, come in contact with the moisture of the ground and by simple absorption con- duct it as the aliment of the plant. There are many ani- mals which have a vegetative life almost as simple as this, are fixed permanently to the spot where they came into existence; others are permitted to change their places of abode, and a provision for nourishment by roots would not answer; hence comes the necessity of a stomach, or reservoir in the interior of the body, into which aliment may be introduced, and transported along with the ani- mal. In many instances this stomach seems to constitute the whole animal, as in a hydatid: it receives such simple fluids as compose the medium in which it resides, and carries on its digestion, with so little change of the ali- mentary matter, that there seems to be nothing of an ex- crementitious kind, as commonly understood, thrown off*. These animals are found abundantly in the waters of tro- pical regions, exist sometimes in the brain of man, and of sheep, in the uterus, and in almost every part of the body. XX1V INTRODUCTION. But, again, there are stomachs of a more complex kind, which have opening into them a great number of absorb- ing orifices, called, in the striking language of Boerhaave, "genuine internal roots." These stomachs may admit fluids only, or they may be large enough to receive con- siderable masses of solid aliment. In the latter case ex- ists the necessity of teeth, or some mechanical means of triturating the solid food into such fine pieces, as will admit of its being exposed by an extensive surface to the action of the stomach. But as much of the matter thus carried in is unfit for assimilation, and there may be even more of it than is required, an intestinal canal is provided, by which it is carried out again. Here then commence the phenomena of a true digestion, with all its modifica- tions and stages. The very simple structure of a plant, and its perma- nent locality is attended with a circulation of its juices equally simple; which is performed and maintained by the capillary attraction of its pores, and by evaporation from its higher and more exposed parts. This circulation is the more rapid as the evaporation becomes greater: but the latter may become changed into absorption by the humidity of the atmosphere; and the circulation be, as a consequence, reversed from the branches to the roots. But it is evident that such animals as possess extensively the powers of locomotion, besides having organs more numerous and more complex than the parallel fibrillae of vegetables, will frequently find themselves in such con- ditions of temperature and locality", that a similar circu- lation of the nutritious fluid in them could not be main- tained. Hence it is necessary to have more powerful and regular agents for carrying on the circulation. They, therefore, are furnished with innumerable biood vessels, called arteries and veins, which have a common centre, the heart, for propelling through them the blood INTRODUCTION. XXV or nutritive fluid to all parts of the system. From the heart being furnished with valves, which are all in one direction, the blood can flow only in a corresponding course; thus it is forced by the heart into the arteries, and after moistening the most minute fibres it is received into the capillary extremities of the veins and brought back to the heart, where it receives another impulse, and performs again the round of the body, and so on in suc- cession. This phenomenon is called the circulation. When it exists in animals, blood is always to be found; for the most part red, but in many species white or trans- parent. The use of the blood in them is to receive from the alimentary canal, from the skin and lungs, such mat- ter as has been assimilated, and to convey it to every part of the body, for the purpose of repairing its waste, or providing for its growth. It is at the very extremities of the arteries that this deposite occurs, and the blood getting into the veins loses its bright vermilion colour, becomes of a modena or dark blue, and is no longer fit for the purposes of life till some of the principles which it has lost by this passage are restored to it. This resto- ration takes place in the lungs, where a sort of combus- tion is performed by the absorption of oxygen. This process is called respiration, and it exists in all things that live, under various modifications of the apparatus performing it. In man it is performed in two cellular air bags, which have a heart independent of the one just mentioned, for propelling the blood through the ra- mifications of their vessels. In fish there are gills, which have their surfaces exposed to the water, and are aerated by the air contained in the water, and the same heart which supplies the general circulation, also fills a large artery, that is distributed very minutely through the gills. But in insects, where there are no blood vessels, and the nutritious fluid is contained in cells, there are, Vol. I.—4 XXVI INTRODUCTION. distributed over their bodies, air tubes, which transmit atmospheric influence. The blood vessels, in addition to the function of carry- ing nutritious matter, perform an essential part of a very different character. All the atoms of which the body is composed, after residing in it for a time, become no longer fit for use; their farther residence is, in fact, in- jurious, and it is necessary to remove them. A system of vessels is provided for this purpose, called the absor- bents, which are the scavengers of the body. Taking up, therefore, these effete atoms, they convey them into the blood vessels, where they are mixed with the common mass of blood. Several organs are provided, as the liver, the kidneys, the surface of the body, and the lungs, through which these effete particles are discharged from the blood in the form of excretions; as the bile, the urine, perspiration, and pulmonary exhalation. We have now sketched the human machine as far as its internal existence, or self-preservation, is concerned in the functions of digestion, circulation, respiration, and excretion. Lfct us proceed in the inquiry by a rapid glance at those organs by which it is put into a relation with surrounding objects, and on which it depends for the sublime operations of the understanding. Sensation is derived from the nervous system, com- posed of the brain, the spinal marrow and the nerves. The latter may be traced to many parts of the body, and are supposed to be distributed to all. They maintain its different sympathies, keep the several organs in one har- monious course of action, and, in some instances at least, are indispensable to the performance of their functions. In addition to these, many of the nerves have at their extremities organs of a particular construction, each fa- shioned in the best manner for the performance of its functions, in making us acquainted with exterior ob- INTRODUCTION* XXVU jects. The interior extremities of all these nerves ter- minate either in the brain or spinal marrow; the exter- nal are the points intended by nature to be affected by the objects around us; but it is indispensable to conscious- ness, that their line of communication with the brain be not interrupted. The sense most extended is that of the touch, which is enjoyed by all parts of the surface of the body; the others are thought, by very respecta- ble physiologists, to be only more exalted modifications of it, and are susceptible of more delicate impressions. It is scarcely necessary to mention that the other sensa- tions are executed by the eye, the ear, the tongue, and the nose. The Sense of Touch is the most important of all, and the least liable to error in its reports. To exercise it, it is necessary for the body, under examination, to come into contact with ours : hence, its operations are so me- chanical, that but little is left to the imagination, and they, therefore, serve to verify and to correct the im- pressions on the other senses, more particularly those on the eye. It is the sense of touch by which we learn ac- curately the dimensions of bodies, and the figures of such as are hard. The hand, or any other part, by be- ing applied to them in various directions, informs us whether they are flat, round or angular. A greater or less degree of pressure informs us whether they are soft or hard, and by rubbing, we ascertain whether they are rough or polished. The resistance they make to mo- tion, teaches us whether they can or cannot be moved, and their being impelled against us shows the momentum with which they act, as well as its direction. Our ideas oNieat and of cold are also derived from this source. It is not asserted that all parts of the surface of the body en- joy equally the sense of touch; on the contrary, this sen- XXV111 INTRODUCTION. sibility is more or less active, according to the organi- zation of the part, and as its nerves are more or less numerous and exposed; hence we find it most exquisite and perfect in the ends of the fingers. This, therefore, being the most important of the senses, the magnitude of its influence on the habits and intelligence of different animals is immense. Man, from the nudity and the delicacy of the tex- ture of his skin, derives, from this source, a discrimina- tion and refinement, in regard to the nature of bodies, much superior to what many other animals possess. The Sight enables us to distinguish the colour, the quantity, and the direction of the rays of light which proceed from a luminous body; or, in other words, to as- certain its situation, size, and figure. In each, however, of the latter we are exposed to great deception; for the rays of light, by falling on a mirror, or any other plane reflecting surface, before they reach the eye, will in- duce us to believe the body to be in that direction. Bo- dies which are near, reflect more rays of light than such as are distant: we thus estimate distance by the eye; but it happens continually, that some bodies naturally reflect more rays than others: in consequence of which a verv luminous body, at a great distance, will frequently be thought to be much nearer to us, than such as are more within our reach. Mistakes of this kind can onlv be cor- rected by the sense of touch, and our habitual reference to it, and continual experience, finally enable us to form prompt and just decisions. The eye, however, infinite- ly exceeds the touch in the rapidity with which it com- municates ideas, and, also, in the extensiveness of its ap- plication in a single moment. It is, therefore, an organ of the first utility in making us acquainted with sur- rounding objects. Man does not possess it to that great INTRODUCTION. xxix perfection that some other animals do; he can neither see as far as the vulture or eagle, nor so minutely as the fly; yet his ingenuity has enabled him to excel both. For, with the telescope, he examines worlds in the im- mensity of space, which, under common examination, are either invisible, or form mere points in the heavens. And with the microscope he sees the texture of the most minute atom. The Ear, along with the powers of articulation, ena- bles the whole human family to make a common stock of the knowledge which each individual may possess. As connected with the preservation of the individual, it is much less important than the eye or the touch; yet, con- sidering it as a means by which we receive knowledge and impart it to others, the aggregate of human intellect depends for its present state and future improvement, es- sentially upon it. In its acuteness, we are much inferior to many other animals; neither have we, by instruments, been able to do much in improving it: yet, by cultiva- tion and by studying its most minute and delicate impres- sions, an endless source of instruction and amusement has been opened to us, in the intonations of language, and in the enrapturing strains of harmony. It eminently qua- lifies man for the social state, occasionally warns him of danger, and allures him to such things as are useful to his subsistence. In regard to the Taste and to the Smell, they make us acquainted only with such objects as are necessary to our subsistence. They are enjoyed too imperfectly by man, for them to become a fruitful source of his intelli- gence. As they principally lead us to filling the sto- mach, and to debasing the intellectual man into the XXX INTRODUCTION. beast, that eats and dies; the wisdom of nature is as fully demonstrated in the imperfection which she has put upon these senses, and our inability to improve them, as in the exalted and varied degrees to which she has carried the others. The keenness of the scent of the hound, and the discriminating nicety of the bee, in opening sources of enjoyment merely physical, would have degraded, instead of elevating us; by engrossing our time and ingenuity, in the development of plea- sures incompatible with our constitutions and destinies. Man being thus constituted, it is worthy of inquiry in what his life consists. According to the celebrated Bi- chat, it is " the aggregate of those functions by which death is resisted. For such, iudeed, is the condition on which we live, that every thing surrounding us has a tendency to produce our dissolution, by the affinities ex- isting between their atoms, and the atoms of which a living body is composed. It is plain, therefore, that the principle of life, like all other principles in nature, in- comprehensible in itself, must be studied by its phe- nomena."* There are two remarkable modifications of life: one is common to the vegetable and to the animal, the other is the exclusive attribute of the latter. Under the first modification, are included assimilation and excretion, which, though exercised under apparently different cir- cumstances in animals and in plants, are probably essen- tially the same in both. This modification is termed by Bichat, Organic Life. By the second modification of life, the animal has a more extended sphere of existence than the vegetable, is put into a certain relation with all the objects that surround him, is made the inhabitant of * Recherches sur la vie et La Mort. INTRODUCTION. XXxi the whole world, and not, like the vegetable, confined for ever to the place of its birth. By it the animal feels, and is conscious of external objects, reflects upon them, moves voluntarily, and can communicate, by the voice, his wants and apprehensions, his pleasures and his pains. The functions included under the second modification, are termed, by Bichat, Animal Life. Each of these lives has two orders of functions, keep- ing up its connexion with the objects destined for its existence. In animal life, one of these orders may be said to commence at the surface of the body, and to be extended towards the centre, the impression of exterior objects affecting first the senses, then the trunks of nerves, and lastly, the brain. A second movement, con- stituting the second order of functions, is afterwards made from the centre to the circumference, by which the influence of the brain is exercised on the organs of locomotion and of voice. These two functions, in ani- mal life, are perfectly equivalent in their operations. He who feels the most, will also act the most. Early life is the period of quick and multiplied sensations, so is it the period of quick and multiplied movements. A par- tial, or a total privation of the sense of sight, causes us to move cautiously and'slowly onwards. The suspension of our communication, through sleep, with exterior ob- jects, causes also a suspension of the faculties of locomo- tion and of voice. In organic life, the first order of functions assimilates to the animal the substances which must nourish him, and includes digestion, circulation, respiration, and nutrition; under the influence of which four functions, every thing must pass before it can be assimilated. But, after a temporary residence, the as- similated particles becoming effete and noxious, have to be carried away out of the body; by which means the XXxii. INTRODUCTION. second order of functions in organic life is established, consisting of absorption, circulation, exhalation, and se- cretion. The two functions of organic life differ, however, from those of animal life, in not observing, on all occasions, an equivalence of action: the diminution of assimilation does not involve a corresponding diminution in excre- tion; hence, follow emaciation and marasmus, conditions in which, assimilation ceasing in part, disassimilation is exercised to the usual extent, or near it. From this sketch, it is seen that the circulation of the blood is the connecting link of the two orders of functions in organic life, as the brain is the connecting link of the two orders of functions in animal life. The blood is, therefore, in fact, composed of two parts or descriptions of matter: one is recrementitial, derived from the aliment, and sub- servient to the renovation and growth of parts; the other is excrementitial, derived from the wrecks of all our organs, and under the necessity of being cast away as useless. M. Bichat thinks the division of life into animal and organic, fully warranted by their differing much from each other in the exterior shape of their respective or- gans,—in their mode of action,—in the duration of their action,—in the effects of custom or habit on them,—in their relation to the moral part of man, and in their vi- tal force. One of the most prominent differences in the two lives, is the symmetry and duplicity of the Organs of Animal Life, and the irregularity in shape of those belonging to Organic Life. The impression of Light is received by. two organs exactly alike. Hearing—Smelling—Touch- ing—are likewise performed by organs having their con- geners on the opposite sides of the body; and even INTRODUCTION. XXxiil Tasting, though apparently performed by one organ, has that organ divided into two equal and symmetrical parts, thus making it like the other organs. The whole exte- rior surface of the body is, indeed, manifestly divided into two equal parts, marked off from each other by the fissure in the nose, the upper lip, the chin, the raphe of the scrotum and perineum, the spinous processes, and the depression in the superior posterior part of the neck. The Brain and Spinal Marrow, as belonging to'animal life, consist of two halves, presenting corresponding ar- rangements in the development of cavities and promi- nences, and so on, and in sending similar nerves to the organs of locomotion and of voice. The organs of organic life are marked, on the contra- ry, by the character of striking dissimilitude in their two halves, as manifested in the liver, the spleen, the stomach, the intestines, the heart, and the great vessels belonging to it. There are, however, some organs of organic life in which the difference is less prominent, as the lungs of the two sides, the pulmonary arteries, the veins, the trachea, the kidneys, the capsulae renales, and the salivary glands. From what has been said, we are, perhaps, prepared to admit with M. Bichat, that animal life is double; that its phenomena being executed after the same manner on both sides of the body, it is very possible for the actions of one side to be suspended or destroyed while those of the other go on. This, in fact, happens in certain pal- sies, where the sensibility and motion of one side are so completely suspended, that it resembles a vegetable; all relation with exterior objects being cut offy and nothing but the function of nutrition being preserved; whereas the other side retains all its animal properties. For these reasons Bichat has very quaintly observed that we Vol. L—5 XXX'lV INTRODUCTION. have a right life and a left life. In organic life, on the contrary, the functions of the two halves Of any organ are so allied, that the lesion of one affects the other. The liver, in a disease on one side, has its functions im- paired throughout: it is the same with the intestinal ca- nal, and with the heart. Congenital deformities are said to be more frequent in the organs of organic life than in those of animal life. Several cases have occurred, and Bichat relates one which happened in his own amphitheatre, where there was a ge- neral displacement of the digestive, the circulatory, the respiratory, and the secretory viscera. The stomach, the spleen, the sigmoid flexure of the colon, the point of the heart, the aorta, and the lung with two lobes, were all on the right side. But the liver, the coecum, the base of the heart, the venae cavae, the vena azygos, and the lung with three lobes were on the left side. All the organs placed beneath the middle line, as the mediastinum, the mesentery, the duodenum, the pancreas, the division of the trachea, were reversed. Latterly I have had occasion to observe, in our own dissecting rooms, two cases of the caput coli removed from the right iliac into the left iliac region; the colon was of the common size and length, and being confined to the left side of the abdo- men, formed there a loop, which ascended into the left hypochondriac region, and then descended as usual. In these cases, as there was no transverse mesocolon, the du- odenum had all the coats of the other intestines; and was not attached to the front of the right kidney and to the spine. One of these was an adult female subject of con- siderable corpulency, the other a corpulent male. * Another difference between organic and animal life ex- ists in the mode of action of their respective organs. Each of the organs of animal life being double, our sensations are the more exact, as there exists between the two im- INTRODUCTION. XXXV pressions, from which they result, a more perfect corre- spondence. We see badly when the images transmitted to the brain are derived through eyes of unequal strength. Without knowing this law as theorists, we instinctively show its influence in shutting one eye while looking through a convex glass; whereby we prevent a confusion of images arising from two impressions of unequal force, con- cerning the same body: when one eye is weaker than the other, we squint involuntarily, and it finally becomes a habit, in order to avoid the confusion of perception from two unequal images on the brain. This accounts for squinting, both in early life, from some congenital cause, and for that squinting, which is the result of inflamma- tion, in more advanced life. A little reflection on this head will satisfy us; for as a single judgment or percep- tion is, for the most part, formed from the two impres- sions, one on each eye, how is it possible that this judg- ment can be accurate, when the same body is presented at the same moment with vivid or faint colours, accord- ingly as it was painted on the strong or weak eye? The Ear is subjected to the same law as the eye. If, in the two sensations composing the act of hearing, one is received upon an organ better developed than the other, and more discriminating in its functions, it will leave an impression more clear and distinct; but the brain being affected simultaneously by the unequal im- pressions, will be the seat of an imperfect conception. This case constitutes a false ear in music, and from the impressions being continually confused, prevents the in- dividual from judging rightly between harmony and dis- sonance. A similar reasoning has been founded by Bichat upon the structure of the Nose, Mouth, and Organs of Touch. He believes also that the brain itself, as the seat of the mind, may become the cause of error in our ideas, when XXXVi INTRODUCTION. the two halves of it are not perfectly alike; for example, if one of the hemispheres be more strongly organized than the other, better developed every where, and more sus- ceptible of a vivid impression. The brain transmits to the soul the impression or impulse derived from the senses, as the latter transmit to the brain their impres- sions; it is, therefore, to be believed that the soul will perceive confusedly, when the hemispheres, being une- qual in force, do not blend into one, the double impres- sion upon them. In proof of this, it is common to see mental derangements depending on the compression of a hemisphere by effused blood, by pus, by depressed bone, and by an exostosis from the internal face of the cranium. Even where every sign of compression is removed, the hemisphere occasionally takes a long time to regain its action, so as to recover from the alienation. This harmony of action exists also in the organs of lo- comotion, and of voice; and any thing which interrupts their symmetry, destroys the precision with which their functions are executed. Opposed to this harmony in the shape and functions of the organs of animal life, the most striking differences may take place between the organs of organic life, with- out much disturbance in the general result. For ex- ample, in disparities of the kidneys, of the lungs, of the salivary glands, &c, their functions are not, by any means, the less perfectly performed. The circulation remains the same in the midst of the frequent varieties of the vascular system on the two sides of the body, whether those varieties exist naturally, or whether they depend upon artificial obliterations of the large vessels as in aneurism. Another very striking difference in the two lives i be observed in the duration of their action. All the INTRODUCTION. xxx vii cretions.proceed uninterruptedly, though not uniformly. Exhalation and absorption ^succeed each other inces- santly; assimilation and dissimilation follow the same rule. On the other hand, every organ of animal life, in the ex- ercise of its functions, has alternations of activity and of complete repose. The senses, fatigued by long appli- cation, are, for the time, disqualified from farther action. —The Ear is no longer sensible of sounds;—The Eye is closed to Light;—Sapid bodies no longer excite the Tongue;—The Nose is insensible to odours;—And the Touch becomes obtuse. Fatigued by the continued ex- ercise of perception, of imagination, and of memory, the brain has to recruit its strength, by a state of complete inactivity for some time. The muscles, relaxed by fa- tigue, are incapable of farther contraction, till they have been permitted to rest; hence the necessary intermission, in every individual, of locomotion and of voice. This intermission of action is sometimes extended to all the organs of animal life at the same time; on other occasions, only a part of them is affected by it. It is in this way that the brain frequently continues in the ac- tive exercise of thought, while the senses, as well as the powers of locomotion and of voice are suspended. In addition to the foregoing views, it has also been sug- gested by Bichat, that another striking difference between organic and animal life, is found in the epoch and mode of their origin. Organic life exists from the first mo- ments of conception; but animal life does not commence till after birth, when exterior objects are established in a certain relation with the individual. It is more than probable, that the function of the Eye, the Ear, the Tongue, and the Nose, does not exist in such manner as to communicate their several sensations in the foetus; and that the enjoyment of a sort of indistinct sense of touch, XXXviU INTRODUCTION. arising from its striking against the parietes of the womb, is the only circumstance which can give the latter any idea of its existence; it is, however, doubtful whether it has even a consciousness on that point. The organic life, on the contrary, of a foetus, though not so compli- cated as afterwards, is still remarkable for the prompti- tude and vigour of some of its functions, particularly of assimilation; and in a very short time after birth, all the organs which it employs reach their highest degree of perfection, and thus present a very different case from the organs of animal life. The distinction of the two lives is farther kept up in their manner of ceasing in old age. Natural death, says Bichat, is remarkable, in terminating animal life almost entirely, a long time before it does organic life. The functions of the first cease successively. The Sight be- comes dim, confused, and finally is extinguished. The Ear receives the impression of sounds indistinctly, then faintly, and afterwards they are entirely lost upon it. The skin becomes shrivelled, hardened, loses many of its vessels, by their obliteration, and is only the seat of an obscure and indistinct touch; the hair and beard be- come white, and fall from it. The Nose loses its sensi- bility to odours. Of all the senses, it has been often re- marked, that the Taste remains the longest, and exhibits the last efforts of animal life. The powers of the mind disappear along with those of the senses. The imagination and the memory are ex- tinguished; the latter, however, under striking circum- stances. The old man forgets, in an instant, what was said to him, because, his external senses being weak- ened, do not confirm sufficiently the impressions on his mind: he is, however, able to recollect the transac- tions of early life, and sometimes retains a vivid im- pression of them. He differs from the infant in this, INTRODUCTION. xxxix that the latter forms his judgments from what is passing, whereas, the former forms his from what has already past. Both are, therefore, liable to great errors; for, the accuracy of knowledge, in regard to things present, can only be obtained by comparing them with other things. Locomotion and voice also participate in the de- cline of the other organs of animal life; their powers are, intrinsically weakened; besides which, a certain degree of inactivity is imposed on them, by the previous decline of the brain and senses. If we now consider, that sleep retrenches about one- third of the whole duration of animal life; that nine months of it are first lost in gestation; and that the ex- tinction of our senses is the inheritance of old age; it will be seen how great is the difference between the whole, duration of animal, and of organic life. It has been remarked by Bichat, that the idea of death is painful to us only because it terminates our animal life, or those functions which put us in relation with sur- rounding objects. This is the privation which plants terror and dismay on the borders of the tomb. It is not the pain of death that we fear, for many dying per- sons would willingly commute death for an uninterrupted series of bodily suffering. But if it were possible for a man to exist whose death would only affect the func- tions of organic life, as the circulation, digestion, and secretions, allowing the exercise of the senses and the mind to continue, this man would view with indifference the extinction of organic life, because he knows that the happiness of living is not attached to it, and that he would remain after this partial death, still in a condition to appreciate all the delightful ties of existence. TABL.E OF COXTEffTS. VOLUME I. BOOK I—SKELETON. Page PART I.—General Anatomy of Natural Skeleton, - - 49 Chap. I.—General Anatomy of Bones, - - 50 Sect. 1.—Number and Texture of Bones, - - 50 2.—Composition of Bones, 55 Chap. II.—Sect. 1. Periosteum, - - - - 62 2.—Medulla, ... 64 Chap. III.—Osteogeny, - - - - - 66 Sect. 1.—Development of Bones, 67 2.—Growth of Bones, - - - - 70 3.—Formation of Callus, - - - 73 PART II—Bones, individually, - - - .75 Chap. I.—Trunk, ..... 76 Sect. 1.—Spine, - - - - - 76 2.—Development of Spine, 87 3.—Uses of Spine, - - - - 88 4.—Ossa Innominata, 95 5.—Pelvis, generally, .... 100 6.—Development of Pelvis, ... 103 7.—Mechanism of Pelvis, - - - 104 8.—Thorax, - - - - 105 9.—Cartilages of Ribs, - - - - 111 10.—Development of Thorax, - - 113 11.—Mechanism of Thorax, - - - 115 Chap. II.—Head, ..... 120 Sect. 1.—Cranium, ----- 120 2.—Individual Bones of Cranium, - - 122 3.—Face, - - - - - 136 Vol. I.—6 xlii CONTENTS. Page Chap. III.—General Considerations on Head, - * 148 Sect. 1.—Sutures, - - - - - 148 2.—Diploic Structure of Cranium, - - 155 3.—Internal Surface of Cranium, - - 157> 4.—External Surface of Head, - *60 5.—-Nasal Cavities, - - - - 164 6.—Orbits of the Eyes, - - "166 7.—National Peculiarities of Face, - - 168 8._Development of Fcetal Head, - - 176 Chap. IV.—Os Hyoides, - - - - 179 V.—Upper Extremities, - - - - 180 Sect. 1.—Shoulder, - - - - 180 2.—Arm, - - - - - 185 3.—Fore Arm, - - - - 188 4.—Hand,.....191 5.—Development of Upper Extremities, - 200' 6.—Mechanism of Upper Extremities, - - 201 7.—Motions of Shoulder, - - 203 8.—Motions of Shoulder Joint, - 204 9.—Motions of Fore Arm, - . . 206 10.—Motions of Hand, - - - - 209 Chap. VI.—Inferior Extremities, ... 212 Sect. 1 .—Thigh Bone, - - - - 212 2.—Leg, ----- 216 3.—Foot, .... .222 4.—Development of Inferior Extremities, - 333 5.—Standing, - 234 6.—Locomotion, - 240 PART III.—Articulations, - - - . _ 251 Chap. I.—Cartilaginous System, - - - 251 Accidental Development of Cartilages, - . 253 Perichondrium, ----- 254 Articular Cartilages, - - - - . 255 Chap. II.—Fibro-Cartilaginous System, - . 256 III.—Ligamentous Tissue, - - - . 257 Sect. 1.— - - - . . 257 2.—Ligaments of Joints, - . _ 26O 3.—Synovial Articular Capsules, - . 26O Chap. IV.—Articulations of Lower Jaw, - - . 263 V.—Ligaments of Spine, - . . 265 VI.—Ligaments of Pelvis, - 274 CONTENTS. xlHi Page Chap. VII.—Articulations of Thorax, - - - 278 VIII.—Articulations of Upper Extremities, - - 283 IX.—Articulations of Lower Extremities, - 299 BOOK II. PART I.—Integuments of the Body, - - - 315 Chap. I.—Cellular Substance, - - - - 315 II.—Adeps, - - - - - - 325 PART II.—Dermoid Covering, - - - - 329 Chap. I.—Of the Skin, generally, - - - - 329 Sect. 1.—Cutis Vera, - - - - 331 2.—ReteMucosum, - - - - 333 3—Cuticula, - - - - 337 Chap. II.—Of the Sebaceous Organs, ... 341 III.—Of the Nails, - - - - 343 IV.—Of the Hairs, - - - - - 345 BOOK III. PART I.—Muscles, - - - - - 351 Chap. I.—General Anatomy of Muscles, - - - 351 II.—Muscular Motion, - - - - 357 III.—Shape of Muscles, - - - - 361 IV.—Tendons,.....362 PART II.—Special Anatomy of Muscles, - - - 365 Chap. I.—Muscles of Head and Neck, - - 365 Sect. 1.—Muscles of Face, - 365 2.—Muscles of Neck, - - - 373 Chap. II.—Muscles of Trunk, - - - - 382 Sect. 1.—Muscles on Front of Thorax, - - 382 2.—Muscles and Fasciae of Abdomen, - - 385 3.—Muscles of Upper and Posterior part of Ab- domen, ..--- 395 4.—Muscles on Posterior Face of Trunk, - 401 Chap. III.—Of the Fascias and Muscles of the Upper Extre- mities, .... 412 Sect. 1.—Fascia, - - - - - 412 2.—Muscles of Shoulder, - - - 415 3.—Muscles of Arm, ... - 417 4.—Muscles of Fore Arm, - - - 420 5.—Muscles of Hand, - -431 xllV CONTENTS. Page Chap. IV.—Of the Fascias and Muscles of the Lower Extre- mities, - - - - - Sect. 1.—Fascia, - - - - " 437 2.—Muscles of Thigh, - - - 443 3.—Muscles of Leg, - 45s 4.—Muscles of Foot, - - - 461 BOOK IV. Organs of Digestion, ----- 467 PART I.—Organs of Mastication and Deglutition, - 469 Chap. I.—Mouth,......469 II.—Teeth,.....471 Sect. 1.—Number of Teeth, and Subdivision, - - 471 2.—Of the Texture and Organization of the Teeth, 474 3.—Gums, - - - - - 478 4 —Formation of Teeth, - - - 479 5.—Dentition, - - - - - 484 6.—Irregularities in Dentition, - - 489 Chap. III.—Tongue, - - - - - 492 Sect. 1.—Muscles of Tongue, ... 492 2.—Mucous Covering of Tongue, - - 494 Chap. IV.—Palate, ----- 497 V.—Glands of Mouth, - - - - 499 Sect. 1.—Muciparous Glands, ... 499 2.—Salivary Glands, - - 500 Chap. VI.—Pharynx and Oesophagus, - 503 Sect. 1.—Pharynx, ----- 503 2.—(Esophagus, - 506 VOLUME. II. BOOK IV. CONTINUED. PART II.—Organs of Assimilation, - - - - 5 Chap. I.—Abdomen, generally, - - . 5 IL—Of the Peritoneum and Serous Membranes, gene- rally, .....10 Sect. 1.—Peritoneum, - - - - - 10 2.—Omenta, - - - - 13 3.—General Anatomy of Serous Membranes, - 18 Chap. III.—Chylopoietic Viscera, - - - 22 Sect. 1.—Stomach, - - - . - 22 2.—Intestinal Canal, - - - 27 3.—Minute Anatomy of the Mucous Coat of the Alimentary Canal, - - - 40 4.—General Anatomy of Mucous Membranes, - 48 Chap. IV.—Assistant Chylopoietic Viscera, - - 54 Sect. 1.—-Liver, - - - - -54 2.—Spleen, ----- 62 3.—Pancreas, - - - - - 66 BOOK V. Of the Urinary Organs, - - - - 69 BOOK VI. Organs of Generation, ----- 83 Chap. I.—Male Organs of Generation, - - - 83 Sect. 1.—Penis, ----- 83 2.—Mucous Glands and Apparatus, - - 88 3.—Testicles, - - - - 90 4.—Muscles and Fasciae of Perineum, - - 97 xlvi CONTENTS. Page 104 - 104 107 Chap. II.—Female Organs of Generation, Sect. 1.—Vulva, - 2.—Vagina, - - - 3.—Uterus, and its Appendages, - - - 110 Chap. III.—Breasts, - - - - - 118 BOOK VII. Organs of Respiration, ----- 123 Chap. I.—Larynx, ----- 123 II.—Of the Trachea and Glands bordering upon it, - 133 Sect. 1.—Trachea, - - - - 133 ^.—Thyroid Gland, - - - - 137 3.—Thymus Gland, - - - - 139 Chap. III.—Lungs, - - - - - 141 BOOK VIII. Circulatory System, ----- 151 PART I—General Anatomy of Circulatory System, - 151 Chap. I.—General Considerations, - - - 151 II.—Arteries, - 164 III.—Veins, ----- 169 IV.—Blood, - - - - .173 Sect. 1.—Serum, - 176 2.—Coagulating Lymph, - - - 177 3.—Red Globules, - 178 PART II.—Special Anatomy of Circulatory System, - 183 Chap. 1.—Heart, ----- 133 II.—Arteries, - 195 Sect. 1—Of the Aorta and the Branches from its Cur- vature, ----- 195 2.—The Carotids and their Branches, - 198 3.—Subclavian and Branches, - - _ 208 4.—Branches of Descending Thoracic Aorta, 220 5.—Branches of Abdominal Aorta, - . 222 6.—Common Iliacs, - 230 7.—Internal Iliacs, - 030 8.—External Iliacs, - 236 Chap. III.—Of the Veins, - 249 Sect. 1.—Veins of Head and Neck, . . 249 2.—Veins of Upper Extremities, - . 258 CONTENTS. xlvii Page Sect. 3.—Veins of Lower Extremities, -^ - 262 4.—Veins of Abdomen, - 264 5.—Vena Portarum, .... 269 Chap. IV.—Peculiarities of the Circulatory System in the Foetus, - - - - - 271 Sect. 1.—Peculiarities of Foetus, - - - 272 2.—Peculiarities of Circulation of Foetus, - 276 Chap. V.—General Anatomy of Absorbent System, - 281 VI.—Special Anatomy of Absorbent System, - 290 Sect. 1.—Absorbents of Head and Neck, - - 290 2.—Absorbents of Upper Extremities, - - 293 3.—Absorbents of Inferior Extremities, - 295 4 —Deep Absorbents of Pelvis, - - - 297 5.—Absorbents of Organs of Digestion, - 299 6.—Absorbents of Viscera of Thorax, - - 305 7.—Absorbents of Parietes of Trunk, - 307 8.—Thoracic Ducts, --■-■- 310 BOOK IX. Of the Nervous System, - - - - 315 PART I.—General Anatomy of the Nervous System, - 315 11.—On the Special Anatomy of the Central Portion of the Nervous System, ... - 325 Chap. I.—Medulla Spinalis, and its Membranes,' - 325 Sect. 1.—Medulla Spinalis, - - - -325 2—Membranes of Spinal Marrow, - - 331 3.—Blood Vessels of Medulla Spinalis, - - 334 Chap. II.—Encephalon, - 335 Sect. 1.—Membranes of Brain, - 336 2.—Medulla Oblongata, - - - 346 3.—Protuberantia Annularis, - - - 350 4._Cerebellum, - - - - 351 .").—Cerebrum, ----- 354 6.—Nerves of Encephalon, - - - 370 7.—Arteries of Brain, - 379 PART III—Senses, ----- 383 Chap. I.—Nose, - - - - - 383 II—Eye, - - - 394 Sect. 1.—Auxiliary parts of Eye, - 394 2.-Eyeball,".....410 xlviii contents. Page Chap. III.—Ear,.....- 430 Sect. 1.—External Ear, - - - - 430 2.—Tympanum, ----- 434 3.—Labyrinth, - - - - 440 4.—Nerves, ----- 446 PART IV.—Special Anatomy of Nerves, - - 451 Chap. I.—Nerves of Encephalon, - 451 Sect. 1.—.....451 2.—Nervus Opticus, - 451 3.—Nervus Motor Oculi, ... 452 4.—Nervus Trochlearis, - - - . 452 5.—Nervus Motor Externus, - - 453 6.—Nervus Trigeminus, ... 453 7.—Nervus Facialis, ... 464 8.—Nervus Hypoglossus, ... 466 9.—Nervus Accessorius, ... 468 10.—Nervus Glosso-Pharyngeus, - 468 11.—Nervus Pneumogastricus, - - 470 Chap. II.—Sympathetic Nerve, - 475 III.—Nerves of Medulla Spinalis, - - 488 Sect. 1.—Upper Nine Spinal Nerves, - - -488 2.—Thoracic Spinal Nerves, - - 499 3.—Abdominal Spinal Nerves, - - - 502 A TREATISE ON ANATOMY. BOOK I. PART I. On the Anatomy of the Skeleton. The skeleton is the bony frame-work of the human body, and, by its hardness and form, retains in proper shape the whole fa- bric ; affords points for the attachment of muscles; and protects many of the viscera. Anatomists call the bones, along with their natural connexions of ligaments, cartilages, and synovial mem- branes, a natural skeleton; and the bones only, but kept together by artificial means, an artificial skeleton. The bones are inflexible, and in a recent state are of a dull white colour, familiar to most persons from its being the same in animals; but they may be made of an ivory whiteness by being macerated and prepared properly. The regional division of the skeleton is into Head, Trunk, Su- perior and Inferior Extremities. If a vertical plane be passed from the top of the head down- wards, through the middle of the skeleton, this plane will divide the latter into two equal portions, called, in common language, the right and the left side of the body. These two sides are per- fectly alike in shape and size. Some of the bones are found in this plane, being intersected by it into two equal parts or halves: others are somewhat removed from it, and are in pairs. This ar- rangement antagonizes the two sides of the body, and qualifies it for all its motions. Vol. I.—7 50 SKELETON. CHAPTER I. OF THE BONES, GENERALLY. SECT. I.--NUMBER, TEXTURE. The number of the bones is commonly the same in every per- son of middle age; but they are less numerous then, than in in- fancy, from several of them having been originally formed in pieces which coalesce. The farther fusion in advanced life, of contiguous bones into each other, diminishes still more their num- ber. It is, however, generally agreed to view the following as distinct;— For the Head—An occipital hone, a frontal, a sphenoidal, an ethmoidal, two parietal; two temporal, each containing the small bones of the tympanum; two superior maxillary, two palate, two malar or zygomatic, two nasal, two unguiform or lachry- mal bones, two inferior turbinated, a vomer, and an inferior max- illary : For the Trunk—Twenty-four true or moveable vertebras, one sacrum, four caudal vertebrae or bones of the coccyx, two inno- minata, twelve ribs on each side; a sternum, in three pieces, however, in the youthful adult: One hyoid, in three pieces, sometimes five in the adult, and situated in the throat: The remaining bones compose the limbs, and are, therefore, in pairs, or correspond exactly on the two sides of the body. They are, For the upper Extremities—The clavicle, the scapula, the os humeri, the radius, the ulna, the eight bones of the carpus, the five bones of the metacarpus, the two phalanges of the thumb, the three phalanges of each of the fingers, the two, and some- times more, sesamoid bones: For the lower Extremities—The os femoris, the tibia, the fibula, the patella, the seven bones of the tarsus, the five of the meta- TEXTURE OF BONES. 51 tarsus, the two phalanges of the big toe, the three phalanges of each of the smaller toes, and the two, sometimes more, sesa- moids. There are, therefore, twenty-two bones to the head, not in- cluding those of the tympanum; fifty-six to the trunk of the body; one insulated bone to the throat; sixty-eight to the two upper limbs; and sixty-four to the two lower limbs. In all, two hun- dred and eleven. The redundancy or the deficiency of the se- samoid bones, in a subject, may cause this number to be slightly increased or diminished. The situation of the bones varies; some are profound, while others approach very near to the surface of the body. They are, as stated, either symmetrical,—that is, consist of two lateral portions precisely alike,—or else in pairs, having a perfect cor- respondence with each other. The symmetrical or bilateral bones are the frontal, the occipital, the sphenoidal, the ethmoi- dal, the vomer, the inferior maxillary, the hyoid, the spinal, and the sternal; and they are situated under the middle vertical line of the body. The pairs are on the sides of the middle line, more or less removed from it. The long bones (ossa longa) are generally cylindrical or pris- matic, and have their extremities enlarged for the purpose of ar- ticulating with adjoining bones. The broad bones (ossa lata) have their shapes diversified by muscular connexion and by the forms of the viscera they contain. The thick bones (ossa crassa) are situated in the vertebral column; and in the hands and feet; and have their surfaces very irregular. The bones present, on their periphery, eminences and cavities, a proper knowledge of which, is of the greatest importance to the surgeon. The former are called apophyses or processes, and are extremely numerous and diversified: they serve for the ori- gin and insertion of muscles, and for furnishing articular faces. The cavities are also numerous: some of them are superficial, and serve for articular surfaces; others for the origin of muscles; for the enlargement of other cavities, as that of the nose and ear; and for purposes which will be mentioned elsewhere. The articular ends of the long bones are called epiphyses, from their being formed from distinct points of ossification, whereas 52 SKELETON. the shaft of the bone is its diaphysis or body, being the part first formed. The epiphysis, therefore, as its name implies, grows upon the other. Many processes grow after the manner of epi- physes, from distinct points of ossification, though they are sel- dom called by the same appellation. This is the case with the trochanters of the os femoris, with the processes of the vertebras, the crista of the ilium, and the tuber of the ischium. Near the centre of some bones a canal is found which passes in an oblique direction, and transmits blood vessels to their inte- rior. There are also, at the extremities of the long bones, at the different points of the thick ones, and near the margins of the flat ones, a great many large orifices, which principally transmit veins: in addition to which, a minute inspection of any bone whatever, will show its whole surface studded with still smaller foramina, also for the purpose of transmitting blood vessels. The density of bones is always well marked, and exceeds much that of other parts of the body. It is, however, variable in dif- ferent bones, and in different places of the same bone: hence their substance has been divided into compact and cellular, of which the former is external and the latter internal. The cellular structure, or substance, grows from the internal surface of the other, and is composed of fibres and small laminae, which pass in every direction, by crossing, uniting, and sepa- rating. The cells, resulting from this arrangement, present a great diversity of form, size, and completion. They are all filled with marrow, and communicate very freely with each other. The latter may be proved in the boiled bone, by the practicabi- lity of filling them all with quicksilver from any given point; and, indeed, by the injection of any matter sufficiently fluid to run. The communications between them are formed by deficiencies in their parietes, after the same manner that the cells of sponge open into each other. This structure does not exist in the ear- liest periods of ossification, when the bones are cartilaginous al- most entirely, but developes itself during the deposite of calca- rious matter. The manner of its formation is imperfectly under- stood, though it may possibly be the result of absorption, and it is not completed in the bones, originally consisting of several pieces, till they are consolidated into one. TEXTURE OF BONES. 53 The compact substance is also formed of fibres and laminae, which, however, are so closely in contact with each other, that the intervals between them are merely microscopical in the greater part of their extent: they become, however, more and more distinct, and larger, near the internal surface and at the extremities of the bone; until the compact tissue is gradually blended with the cellular structure, or lost in it. Its fibres are directed longitudinally in the cylindrical bones, radiate from the centres of the flat ones, and are blended so as to render it impos- sible to trace them in the thick ones. This disposition in the flat bones is much better seen in early life; subsequently, it becomes in- distinct. The compact tissue, particularly in the cylindrical bones, has in it a multitude of longitudinal canals, visible to the micro- scope, and some of them to the naked eye, which contain ves- sels and medullary matter. Those canals, originally described by Havers, are, according to the estimate of M. Beclard, about one-twentieth of a line in diameter, on an average; they are, however, generally larger near the interior than the exterior sur- face of the bones, and have frequent lateral communications with the cellular structure, and with the external surface. The compact and the cellular structures present themselves under different circumstances in the three species of bones. The compact has an unusual thickness in the bodies or diaphyses of the long bones, and is accumulated in quantities particularly great in their middle, which, from its position, is more exposed than their extremities, to fracture from falls, blows, and violent muscular efforts. But as this texture approaches the extremi- ties of the bones it is reduced to a very thin lamina, merely suf- ficient to enclose the cellular structure and to furnish a smooth articular face for the joints. The cellular structure, on the con- trary, in the long bones, is most abundant in their extremities, constituting their bulk there, and is least so in their bodies. It is so scattered at the latter place as to leave a cylindrical canal in their middle, almost uninterrupted for some inches. This ca- nal, cellular in its periphery, has its more interior parts traversed in every direction by an extremely delicate filamentous bony mat- ter, which, from the fineness of its threads and the wide inter- vals between them, has been, not unaptly, compared to the meshes of a net, and is, therefore, spoken of specially under the 54 SKELETON. name of the reticulated tissue of the bones, in contradistinction to the cellular. It is formed on the same principle with the latter; and though the term, from that circumstance, has been rejected, upon high authority, as superfluous, it appears worthy of reten- tion, as it expresses a fact of some importance. Too weak to contribute in an appreciable degree to the strength of the bone, the reticulated tissue seems principally useful in supporting the marrow and in giving attachment to its membrane. The extre- mities of this canal gradually disappear by becoming more and more spongy. In the flat bones, the compact tissue forms only their surface or periphery, and is of inconsiderable but generally uniform thick- ness; the space within is filled up with the cellular tissue, which is rather more laminated than it is in the long bones. In the thick or round bones, the compact tissue forms their periphery also; but, generally, it is thinner than in the flat: their interior is likewise filled up by the cellular tissue, and does not present differences of importance, from the ends of the long . bones. A simple experiment on any of the cylindrical bones will prove that the tumefaction of their extremities does not add propor- tionately to their weight, as one inch or any other given section of the compact part weighs very nearly the same with a section of equal length from the cellular extremities. The swelling at the ends of the bones adds much to the safety of their articular union, as the extent of the surfaces is thereby much increased, and, consequently, they are less liable to displacement. The cy- lindrical and the cellular cavities, thus formed in the long bones, by increasing the volume of the latter, add greatly to their strength. Dr. Physick has demonstrated this most satisfactorily by a scroll of paper, which, on being rolled up successively, into cylinders of various sizes, has, like a lever, its power of sustain- ing lateral pressure on one of its extremities, continually in- creased as its volume or diameter is augmented, until the latter reaches a certain extent. The same highly distinguished teacher has also pointed out another very important advantage of the cellular structure. It is that of serving to diminish, and in many cases to prevent concussion of the brain, and of the other visce- ra, in falls and in blows. The opinion is verified by his demon- COMPOSITION OF BONES. 55 strating the momentum, which is communicated through a series of five ivory balls suspended by threads, when one of them is withdrawn from the others, and allowed to impel them by its fall. The momentum is so completely transmitted through the series, that the ball at the farthest end is impelled almost to the distance, from which the first one fell. This familiar experiment, used as a preliminary test to the accuracy of his views, is imme- diately succeeded by his substituting for the middle one of ivory, a ball made of the cellular structure of bone. The same degree of impulsion now communicated at one end of the series, is al- most lost, or rather neutralized, in the meanderings of the cellu- lar structure of the substitute; and particularly if the latter be previously filled with tallow or well soaked in water, so as to bring it to a condition of elasticity resembling the living state. sect. u.—Composition of bones. The bones under every modification of shape and mechanical arrangement, are constituted by precisely the same elementary matters: the principal of which are an animal and an earthy substance, in intimate combination. Their minute analysis, ac- cording, to Berzelius, when they are deprived of water and of marrow, affords 32 parts of gelatine, completely soluble in wa- ter; 1 part of insoluble animal matter; 51 parts phosphate of lime; 11 carbonate of lime; 2 fluate of lime; 1 phosphate of magnesia; 1 soda and muriate of soda. There are some other ingredients manifested in the analysis of Fourcroy and Vauque- lin, as iron, manganese, silex, alumine, and phosphate of ammo- nia. The relative proportion of these ingredients is not uniform- ly the same, as the bones of the cranium, and the petrous por- tion of the temporal, in a remarkable degree, have more calca- rious matter in them, than the other bones of the same skeleton. There is also a considerable diversity in individuals, according to their age and to certain morbid affections. The earthy matter gives to bones their hardness and want of flexibility, and is easily insulated from the other by combustion; which, in destroying the animal part, leaves the earthy in a white friable state, but preserving the original form of the bone. If the heat be of a high degree, the calcarious part becomes vitri- 56 SKELETON. fied, and its cells are blended by fusion. The action of the at- mosphere, long continued, also divests the bones of their ani- mal matter, and the calcarious then falls into a powder. If the bones be kept beneath the surface of the ground, by which they are less affected by changes in temperature and moisture, the animal matter remains for an immense number of years. I have seen in the Hunterian Museum of London, preparations of the teeth of the Mastodon or Mammoth, in which the ani- mal matter was entire, notwithstanding the great lapse of years since it was in a living state. I am also informed by Mr. Say, a distinguished naturalist, that animal matter has been detected in fossil shells, the existence of which was probably anterior to that of the human family. The phosphoric acid of bones gives them a luminous appearance at night. Bichat says, that in these cases he has found an oily exudation on the luminous points, probably from the marrow or contiguous soft parts. This phenomenon will account for many of the superstitions which in all ages have affected ignorant minds, on the subject of burying grounds. The immersion of a bone in diluted muriatic acid is the best method of demonstrating the animal part in a separate state. The strong affinity of the acid for the earthy part, and the so- luble nature of the salt thus formed, leave the animal matter insulated. In this state it preserves the original form of the bone, is cartilaginous, flexible, and elastic. The action of hot water alone, upon a bone, by continued boiling, will, from the soluble nature of the cartilage, separate the latter from the earthy part, and convert it into gelatine. The gelatine may be precipitated afterwards from the water by tannin. The mode of this combination of animal and of earthy matter is not un- derstood, but it is generally supposed to exist by the extremely small cavities of the former receiving earthy particles in the same way that sponge holds water. There are no means for investigating the minute anatomy of the bones more favourable than the removal of the earthy part by an acid. The cartilage thus left is the complete mould in every particular of form, into which the particles of calcarious matter were deposited. In this state, the compact part of the bodies of the cylindrical bones may be separated into laminae; COMPOSITION OF BONES. 57 and these lamina?, by the aid of a pin or fine-pointed instru- ment, may be subdivided into fibres. The laminae, though enclosing one another, are not exactly concentric. I have observed, that the more superficial come off with great uniformity and ease in the adult bone, but their in- tertexture continually increases towards the centre. Bichat has objected to this dissection of the bones, that the laminae are not formed in nature, but factitiously, by the art of the anatomist, and that their thickness depends entirely on the point at which one chooses to separate them; they, therefore, may be made thick or thin at pleasure. It does not appear to me difficult to account for the manner in which this laminated arrangement is produced. The longitudinal fibres of the bones adhere with more strength to each other at their sides than they do to those above or below, in consequence of which a plane of these fibres may be raised at any place and of any thickness. This fact does not involve the inference that the bones are formed by a successive deposite of one lamina over another; it merely in- culcates the mode of union between the fibres. I am, however, inclined to the opinion that the periosteum secretes the exter- nal laminae in the adult bone, inasmuch as they separate with unusual facility from the subjacent one. We know that the pe- riosteum has the power of this secretion, as a laminated depo- site of bone on the roots of the adult teeth frequently met withr proves without doubt, as also the phenomena of necrosis. The disposition of the cylindrical bones to separate into laminae, i& also constantly manifested in such as are simply exposed to the atmosphere. The opinion of the laminated and fibrous arrangement of bones has been very generally adopted by anatomists. Mal- pighi, whose name is indissolubly connected with minute inves- tigations in anatomy, taught it. Gagliardi, also, in admitting it, thought he saw pins of different forms for holding the lami- nae together. Havers also saw the laminated and fibrous struc- ture. In short, there are few of the older anatomists who have not given fully into the opinion. Among the moderns, the late M. Beclard, the distinguished and able Professor of Anatomy in the School of Medicine in Paris, says, that when the earth is removed from bones by an acid, if they be softened by ma- Vol. I.—S 58 SKELETON. . • ceration in water, the compact substance, which previously of- fered no apparent texture, is separated into laminae, united by fibres; the laminae themselves, at a later period, separate them- selves into fibres; which, by a farther continuation of the pro- cess swell, and become areolar and soft. A long bone examined after this process, divides in its body into several laminae, the most external of which envelops the rest; and the remainder, by rarefying.themselves towards the extremities, are continuous with the cellular structure there. J. F. Meckel, of the University of Halle, has furnished the following account in his General Anatomy of the Bones:— " The fibres and the laminae which constitute the bones are not simply applied one against the other, so as to extend the whole length, breadth, or thickness of a bone, or to go from its centre to the circumference. They lean in so many different ways, one against another, and unite so frequently by trans- verse and oblique appendages or processes, that some great ana- tomists, deceived by this arrangement, have doubted the fibrous structure of bones. Nevertheless, their opinion is not perfect- ly correct. In spite of those inflections and anastomoses of fibres, the fibrous structure always remains very apparent; and one is warranted in saying, that the dimension of length ex- ceeds the two others, in the texture of many bones. This pre- dominance is chiefly well marked in the first periods of -osteo- geny; for, at a later time, the fibres are so applied against each other, as scarcely to be distinguished. But these longitudinal fibres never exist alone; there are many oblique or transverse ones from the first periods of ossification: and they are even from the beginning so multiplied, that the number of longitu- dinal fibres does not prevail over them so much as at a subse- quent period, when the fibres approach nearer, in such way that the transverse become oblique; until at last, from the increase of the bone, the latter, at first view, seems to be composed only of longitudinal fibres. The transverse and oblique fibres do not form a separate system; but continue uninterruptedly with the longitudinal, which they unite to each other."* * Manuel D'Anat. Gen. Desc. et Path, traduit de L'Allemand par Jourdan et Breschet. Paris, 1825. COMPOSITION OF BONES. 59 The venerable Scarpa, some years ago, advanced opinions ad- verse to the laminated and fibrous tissue of bones:* the latter doctrine he was induced to think a mere mistake, arising from careless observation. Founding his own views upon what he had seen in the growing bone, in the adult bone when its earthy parts were removed by an acid, and upon certain cases of dis- ease attended with inflammation of the bone; he denied, with- out reservation, the existence of laminae and fibres in bones, de- claring that even the hardest of them were cellular or reticu- lated. It appears to me, in looking over his paper, that a de- sire to overthrow old doctrines and to establish new ones, has induced him to make one omission in the report of his experi- ments, otherwise unaccountable in a man of his general intelli- gence and candour. Having softened the cylindrical bones in an acid, he next proceeds to a long continued maceration of them; he finds, as other persons have done, the gelatine of the bone finally resolving itself jnto a soft cottony tissue. He has made but one jump from the immersion in the acid to the last stage of the process of maceration. Now, if in a short time after the bone had been softened in the acid, he had made an intermediate experiment, he would, no doubt, like all other in- quirers, have found that the gelatinous part of the cylindrical bones was readily separable into laminae; and that by a pin or needle these laminae could be split into fibres, the greater part of which are longitudinal; and that pounding the ends of these fibres with a hammer would resolve them into a very fine pe- nicillous structure. There is no objection to the conclusion, that these laminae and fibres, as a final condition, produce a very fine microscopical cellular arrangement, which may be made more apparent in being distended by the development of ga- seous substances, arising from putrefaction or maceration; but there is reason for a decided opposition to the assertion of there being no fibres in bones, when I have daily under my eyes pre- parations showing them; some of which demonstrate the fibres running principally longitudinally, others spirally, like the grain of a twisted tree, and others having a mixed course. * A Scarpa. De penitiori ossium structura commentavius. Lips. 1795. See also Anatomical Investigations, Philadelphia, 1824, by the late J. D. Godman, M. D., for an English translation of the same. ¥■ 60 SKELETON. Upon the whole, the description cited from Meckel, exhibits this subject in a just and accurate manner. The more obvious arrangement of the cellular and compact structures of the bones, indicates a considerable difference in their intimate texture: they are, nevertheless, closely allied; for one structure is converted, alternately, into another by dis- ease, of which specimens abound in the Wistar Museum. In both cases, from the fibres are formed cells which exist every where, and are only larger and more distinct in what we call the cellular structure; but the compact part has also its cells, though they are smaller, more flattened, and for the most part microscopical. The blood vessels of the bones, though small, are very nu- merous. This is well established, by the success of fine injec- tions, which in the young bone communicate a general tinge: and by scraping the periosteum from living bones, whereby their surface in a little time becomes covered with blood, ef- fused from the ruptured vessels. In those operations for exfo- liation from the internal surfaces of the cylindrical bones, where it is necessary to excavate the bone extensively, in order to re- move all the detached pieces; unless the general circulation of the limb be previously arrested by the tourniquet, the cavity of the bone is flooded with blood. Bichat has also remarked, that the blood vessels of the bones become unusually turgid and congested, in cases of drowning or strangulation. • The arteries which supply the bones, from their mode of dis- tribution, are referred to three classes. The most numerous and the smallest, are those which penetrate from the periosteum, by the capillary pores found over the whole surface of the bones. The next are those which penetrate the larger forami- na at the extremities of the long bones, and at different points of the surface of others. And the third class, called nourish- ing, amounts to but one artery for each of the cylindrical bones which penetrates by an appropriate canal, as mentioned, com- monly near the centre of the bone. The arteries of the two first classes are generally extremely small. They ramify upon the compact and cellular structure, penetrating it in every direction. At death, they are common- COMPOSITION OF BONES. 61 ly filled with blood, which renders the injection of them diffi- cult. The third, or, as commonly called, the nutritious artery, is of a magnitude proportioned to the bone to be supplied. Be- ing single in every instance, it passes through the compact tis- sue, and having reached the medullary cavity, it divides imme- diately into two branches; each of which, in diverging from its fellow, goes towards its respective extremity of the bone. These branches ramify into countless capillary vessels upon the mem- brane containing the marrow,* and finally terminate by free anastomosis with the extreme branches of the two other sys- tems. The veins of the bones are very abundant: they are uniform- ly found in company with the branches of the third, or nutri- tious arteries, and their common trunk goes out at the nutri- tious foramen into the general circulation. These ramifications have been long known, and bring back the blood from the me- dullary membrane only. The veins which receive the blood of the other arteries do not attend them, and were first of all found in the diploic structure of the cranium, which led to the disco- very of them in all the other bones. The honour of the ori- ginal observation has been claimed respectively by two very distinguished men of Paris, MM. Dupuytrenf and Chaussier.J These veins issue from the bones by numerous openings dis- tinct from those furnishing a passage to the arteries. This cir- cumstance is remarkably well seen in the flat and thick bones and at the extremities of the cylindrical ones. Having left the bone, they terminate, after a short course, in the common ve- nous system. They arise exclusively from the spongy and com- pact structure, by extremely fine arborescent branches, which, uniting successively, form trunks; these trunks penetrate the compact tissue, and escape from the bone by orifices uniformly smaller than the bony canals, of which they are the termina- tions. The canals are formed of compact substance, continued from the external surface of the bone, and are lined by the con- tained veins. The parietes of the canals are penetrated by * Would not this furnish a hint, that the arteries which secrete fat are different from other arteries, and that this distinction may prevail generally? f Propositions sur quelques points d'Anatomie, de Physiologie, &c. Paris, 1803. * Exposition de la Structure de l'Encephale. Paris, 1807. 62 SKELETON. smaller veins entering into the larger. M. Dupuytren is of opinion, that only the internal membrane of the venous system exists in this set of veins; that it adheres closely to the bone, so as to be incapable of exerting any action upon the blood; that it is very thin, weak, transparent, and is thrown into nu- merous valves. Lymphatic vessels are generally seen only on the surface of the bones. Mr. Cruikshank, however, on one occasion, while injecting the intercostal lymphatics, passed his mercury into the absorbents of a vertebra, and afterwards saw them ramifying through its substance;* a fact which, along with what is known of the power of exfoliation in bones, proves sufficiently the ex- istence of such vessels in them. Nerves have also been traced into them, accompanying the nutritious arteries.f CHAPTER II. SECT. I.—OF THE PERIOSTEUM. The membrane which surrounds the bones is called perios- teum, and is extended over their whole surface, excepting that covered by the articular cartilages. As this membrane ap- proaches the extremities of the bones, it is blended with the li- gaments uniting them to each other, from which the ancients adopted the opinion, that the ligaments and periosteum were the same. Many fibres pass from the periosteum to the bone, by which it is caused to adhere. These fibres are more nume- rous and stronger at the extremities than in the middle of the cylindrical bones; also upon the thick bones, than upon the flat ones. The blood vessels of the bones accompany these fibres and contribute to the adhesion. The periosteum is united to the muscles and to the parts lying upon it, by cellular substance. The adhesion of the periosteum to the bones varies in the se- veral periods of life. In infancy it may be separated from them • Anatomy of Absorbing Vessels, p. 98. London, 1790. f Beclard, Elemens d'Anatomie Generate. Paris, 1823. OF THE PERIOSTEUM. 63 with great facility: in the adult it adheres more strongly in con- sequence of its internal face having taken on a secretion of bone, by which it is blended intimately with the bone it surrounds; and in old age it is still more adherent, from the progress of its ossification. It is thick and soft in the infant, and becomes thinner and more compact as life advances. The organization of the periosteum is fibrous, and the fibres pass very much in the same direction with the fibres of the bones; excepting the flat bones, on which' it is not radiated. These fibres have different lengths, the more superficial are longer, while the more deeply seated extend but a small dis- tance. Inflammation developes the fibres in a striking manner, by occasionally making the membrane as thick as an aponeuro- tic expansion. The blood vessels of the periosteum are numerous, and can be easily injected. They come from the contiguous trunks, and ramify minutely, into a vascular net-work, many of whose branches penetrate into the bone, and have the distribution al- ready mentioned. A few lymphatic vessels have been observed in it. Its nerves have not been clearly discovered, though the sensation of extreme pain, when violence is done to it in an in- flamed state, may be thought a proof of their existence. In health its sensations are null, or extremely obscure. The periosteum receives the insertion of tendons, of liga- ments, and of the aponeuroses. In early life, owing to the slight attachment of this membrane to the bones, all these parts may be torn from them, with but comparatively little force. Bichat* having advocated the opinion, that the internal laminae of the periosteum becomes ossified in the adult, considered that as a means by which all the afore-mentioned insertions into it became identified with the bones. This will aecount for the great degree of tenacity with which they adhere, and the im- mense force they are capable of sustaining, without being de- tached from their insertions. In this tendency to ossify, the periosteum manifests a great similitude to other fibrous mem- branes, as the dura mater, the sclerotica, and the tendons. The use of the periosteum is to conduct the blood vessels to * Anatomie Generate. 64 SKELETON. the bones, to protect the latter from the impression of the mus- cles, and other organs, which come in contact with them, to keep the ossification of the bones within its proper boundaries, and to give shape to them; and, finally, as has been suggested by Dr. Physick, it exerts a very happy influence in turning from the bones suppurations in their vicinity, wrhich would otherwise be pernicious to them. SECT. II.--OF THE MEDULLA, AND ITS MEMBRANE, CALLED THE INTERNAL PERIOSTEUM. A greasy substance, as already stated, fills the cells of the bones: it does not, in its composition, differ from common fat: its granuli, however, seem to be somewhat finer. From its resemblance in position to the pith of vegetables, it has ob- tained the name of medulla or marrow. It is contained in a very fine cellular and vascular membrane, lining the internal cavities of the bones, and sending into their compact substance very delicate filaments. The existence of this membrane has been denied, but it may be established by sawing a bone in two, and approaching the cut end to the fire, so as to melt out the marrow, or by immersing it in an acid, in which case the mem- brane becomes crisp and distinct. Its delicacy is so extreme that it can only be compared to a spider's web. In this state it may be traced, lining the whole cylindrical cavity of the long bones, and extending itself to their extremities. It also exists in the diploic or cellular structure of all the other bones; but it is scarcely possible to demonstrate it there in a very distinct manner, owing to its extreme tenuity. The medullary membrane is composed principally of the mi- nute and numerous blood vessels spent upon the internal sur- face of the bones, aided by a very fine, soft, cellular tissue, merely sufficient in quantity to fill up the meshes between the frequent anastomoses of the vessels. From the latter cause it is compared to the pia mater and to the omentum. It has be'en stated, that its blood was derived from the nutritious artery, which communicates freely with the.other arteries of the bones! This membrane is so arranged as to form along the course of the blood vessels small vesicular appendages which contain the MEDULLA, AND ITS MEMBRANE. 65 marrow, and bear some analogy to a thick bunch of grapes, hanging from the several pedicles of the stem. Its nerves are extremely small; they enter by the nutritious foramen, and have been particularly observed by Wrisberg and Klint* They have not been traced ramifying in the substance of the bone, but follow for some distance the course of the prin- cipal arteries. With the exception of Mr. Cruikshank's soli- tary injection of a vertebra, no lymphatics have been observed satisfactorily on it, and such trunks as are supposed^) come* from that source, have not been traced nearer toJ^Rm the ori fice of the nutritious canal. ^^^t ^ Some differences exist in the nature of the con medullary membrane; for example, that part of *t wlitfch is fleeted over the cells in the extremities of the long bones, art? in the whole interior of the flat, and of the thick ones, contains a much more bloody and watery marrow, than what is found in the cylindrical cavities of the long bones: the latter, indeed, re- sembles closely common adeps, presenting no essential diffe- rences from it. These circumstances have given occasion, with- out a material distinction of texture, to divide the medullary membrane into two varieties. * That variety contained in the cellular extremities of the long bones, and in the spongy bones generally, is in a superior de- gree vascular. The part within the meshes of its vessels is, however, so imperfect, that Bichat declared his inability to find it, and that the number of the fine vessels was what gave, falla- ciously, the appearance of a membrane; while, in fact, the in- tervals between them were large, to allow the fat to come into contact with the naked bone. The probability of this defi- ciency is confirmed by the circumstance, that no one pretends to have found a membrane in the microscopical pores of ihe compact substance, yet the existence of fat in it is proved by its becoming greasy when insulated and exposed to heat. It is from the great abundance of blood in this variety of the me- dullary tissue, that the proportion of its adeps is small. The second variety of medullary membrane is displayed in the cells of the diaphyses or bodies of the long bones. Its mem- * B^clard, loc. cit. Vol. I.—9 66 SKELETON. branous cells communicate freely with one another when the membrane is entire; but, according to the observations of Bi- chat, not with such as are in the epiphyses of the bones; and the line of demarkation is abrupt and well defined. This is proved by attempts to inflate the one from the other; the air, in such cases, passes with great difficulty. The texture of this medullary membrane, from its extreme delicacy in a natural state, is rather obscure, but it is occasionally well developed in disease.^Its sensibility has not been very apparent in such cases of arWbtotion as I have seen, though it is said, by some, JoJje exlretrTely exquisite. In whatever degree its sensibility l^rets in different subjects, it is always more apparent in the middle than near the extremities of the long bones; which may be accounted for by its nerves always entering at the nutritious foramen, and extending from thence towards the extremities. The medullary membrane, besides its use in secreting the marrow, is highly serviceable to the nutrition of the bones, as proved in the experiments of Trojat, who, by destroying it, produced their death, and an artificial necrosis, which was cured in the usual way by a new secretion of bone from the perios- teum. The marrow which it contains in the adult is not per- ceptible in the foetus. Moreover, the quality of this marrow is varied by disease: in consumption, dropsy, and other ailments attended with great emaciation, a considerable part of it is ab- sorbed, and a serous fluid deposited in its place; a circumstance well known to those who clean skeletons. CHAPTER III. ON OSTEOGENY. SECT. I.--OF THE DEVELOPMENT OF THE BONES. At birth, though the skeleton is sufficiently solid to pre- serve the shape of the individual, yet it is very imperfect in many particulars, which will be pointed out more in detail hereafter. At present it may be stated, that the ends of all the DEVELOPMENT OF BONES. 67 long bones are cartilaginous—the carpus and tarsus are nearly in the same state—the vertebrae, true and false, have their pro- cesses very imperfect; and consist, each, in several distinct pieces, united by the remains of the cartilaginous state. Seve- ral of the bones of the head are in the latter condition; and the sutures are so imperfect that the flat bones readily ride over each other from the thinness of their edges, and also have the angles rounded, which occasions the vacancies called fontanels. From the early embryo state to the completion of the skele- ton, three stages are observable in the progress of ossification; the first is mucous or pulpy, the second cartilaginous, and tj^ft third osseous. I. The mucous stage is observable at a very early period af- ter the embryo has been received into the womb, and presents itself under two modifications. In the one, from the general softness of the whole structure of the embryo, and from the apparently homogeneous nature of its constituents, the mucous rudiments do not distinguish themselves from the other parts. This condition, however, is soon changed into one, and that be- fore the expiration of the first month of gestation, in which they assume a solidity and colour, which mark them off, both to the eye and to the touch, from the still softer parts surround- ing them. II. About the expiration of the first month the mucous stage is converted into the cartilaginous, and the consistence of the bones then increases continually by the accumulation of gela- tine. Bichat makes a remark on this subject which has been confirmed by the experiments of Scarpa, though erroneous de- ductions have been made by the latter: that we do not see, during the formation of the cartilages, those longitudinal striae in the long bones, radiated in the flat, and mixed in the thick bones, which distinguish the osseous state. The cartilaginous state presents another peculiarity worthy of observation: all the bones which in a more advanced stage are to be united by cartilage, as the vertebrae, those of the pelvis, and of the head, make, collectively, but one piece; while those which are to be united by ligament, and consequently to be moveable, as the fe- 68 SKELETON. mur, the tibia, the clavicle, and so on, are respectively insulated. In the cartilaginous state the bones have neither cells nor medul- lary cavities, and consist in a solid, homogeneous mass, the form of which is sufficiently definite: and has its surface covered by periosteum. The flat bones of the cranium seem to be an exception to the general rule of a preliminary cartilaginous state, and are com- monly thought to be such. Their appearance is delusive, from the cartilage being extremely soft and thin, and concealed by the pericranium on the one side, and the dura mater on the Other; but a careful dissection enables one to distinguish it from this double envelope.* III. The osseous matter begins to be deposed when the rudi- ments of the bone have become entirely cartilaginous, with the exception of a few mucous points. In certain bones this change is observable about the commencement of the second month t after conception: J. F. Meckel has placed it about the eighth week. The colour of the cartilage first becomes deeper; and in its middle, where ossification is to commence, is of a well marked yellow. The blood vessels, which before this carried only the transparent part of the blood, now dilate, so as to ad- mit the red particles, and a red point is perceived, called the punctum ossificationis, from its receiving the first calcarious de- posite. This deposite is always near the very centre of the cartilaginous rudiment, and not at its surface; the portion of cartilage nearest to it is of a red colour; but, a little farther off, opaque and hollowed into canals. The ossification increases on its surface, and in its interstices, by continual deposites, which are always preceded by the condition of the cartilage just men- tioned. The canals of the cartilage transmit the blood vessels and are large at the beginning of ossification; but, as the pro- cess advances and is completed, they diminish gradually, and finally disappear. The progress of ossification is somewhat modified in the three classes of bones. • Bichat, loc. cit. t Beclard, loc. cit. Bichat, loc. cit. DEVELOPMENT OF BONES. , 63 In the long bones a small ring is observed to form early near their centre, and to be perforated on one side by the nutritious artery. This ring has its parietes thin, but broad, and its cavi- ty is the beginning of the medullary canal. It is formed of very delicate fibres which advance towards the extremities of the bone,* and at the same time increase in thickness; so that at birth, the body or diaphysis is generally finished. Common- ly, at a period subsequent to birth, but differing in the several bones, their cartilaginous epiphyses also begin to ossify, by the development in their centre of points of ossification, which pre- sent the phenomena mentioned in the last paragraph but one. The cartilaginous state gradually disappears by retiring from the articular end of the bone towards its diaphysis; and, just before its complete removal, it appears as a thin lamina, gluing the end or epiphysis of the bone to its body. Several of the apophyses of the long bones are also formed from distinct points of ossification. The ossification of the flat or broad bones begins by one or more points, according to the bone being of a simple shape as the parietal; of a double shape or symmetrical, as the frontal, where there are two points of ossification; and of a compound shape, as the occipital and temporal, where there are several points. The commencement of ossification there, is also mani- fested by the appearance of a red vascular spot, in which the osseous matter is deposited, and from which it progresses in ra- diated fibres. The periphery of this circle of rays presents in- tervals between the fibres, giving it the appearance of the teeth of a fine comb: these intervals are subsequently filled up by the sections of radii starting from them, and so on successively till the bone is finished. In the infantile head the several radii grow with a pace nearly equal; so that where the bones are an- gular, the angles being most distant from the centre of ossifica- tion are finished last of all, from which arise the fontanels. Where the bones are intended to be kept distinct from each other, their fusion is prevented by a membranous partition; but when they are to coalesce into one piece, only cartilage is found, which is subsequently ossified. * Bichat, loc. cit. 70 SKELETON. In some of the flat bones, as the sternum and the sacrum, there are, first of all, a great many distinct points of ossification, which quickly unite into a smaller number: they then remain stationary for a number of years, but finally all unite into but one piece. The ossification of the thick bones begins by one or more points, according to the simplicity or complexity of their figures. The bones of the tarsus and of the carpus have each but one point, while those of the spine have several. The two former are almost entirely cartilaginous at birth. The remaining phe- nomena of ossification in these several bones are the same as has been mentioned. SECT. II.--ON THE MANNER IN WHICH BONES GROW. After the cartilaginous condition of the bones has been sup- plied by the complete deposite of osseous matter, and they are finished with the exception of the epiphyses being fused into the body, the bones still continue to grow till the individual has reached a full stature. This is effected by the successive addition of new matter to the old. The long bones lengthen at their extremities: this is proved by the following experiment of Mr. John Hunter.* Having exposed the tibia of a pig, he bored a hole into each extremity of the diaphysis and inserted a shot, the distance between the two shots was then accurately taken. Some months afterwards, when the animal had increased considerably in size, the same bone was examined, and the shots were found precisely at their original distance from each other, but the extremities of the bone had extended themselves much beyond their first distance from the shots. The flat bones in- crease in breadth by a deposite at their margins, a circumstance which has been known a long time, but it required the ingenui- ty of Mr. Hunter to prove conclusively that the long bones in- crease in length by a similar process, and not by interstitial de- posite, as Duhamel thought. This observation explains most satisfactorily the use of the cartilage between the diaphysis and the epiphysis in all bones; that it is merely interposed for the * Transactions of a Society for Improvement, vol. ii. London, 1800. Experi- ments and Observations on the Growth of Bones. GROWTH OF BONES. 71 purpose of offering the least possible resistance to the new os- seous fibres, which grow from the epiphyses and from the dia- physes; and that it is kept for this end, without any material change in thickness, from the fourth or fifth year to the six- teenth or eighteenth, when it disappears, because there is no longer any use for it, in consequence of the bones having at- tained their full size. The epiphyses are then manifestly intended to favour the elongation of the bodies and the development of the extremi- ties of the long bones; to suit the same purposes in some of the flat bones, as those of the pelvis, and to permit the general de- velopment of the bodies of the vertebrae. The ossification of the epiphyses commences in some bones about fifteen days be- fore birth, as in the inferior extremity of the thigh bone, and in others, as those of the ossa innominata, not till the fifteenth year or thereabouts. Many of the processes from the bones, which are also epiphyses, as the trochanters of the os femoris, the tuber of the ischium, the acromion scapulae, the seven pro- cesses of a vertebra, and so on, are developed in the same way. The time at which they all are thoroughly fused into the bones to which they belong, extends from the fifteenth to the twenty- fifth year; depending upon the individual bone, and upon vari- eties of constitution in different persons: though this process may be considered as completed, generally, in the female at the age of eighteen, and in the male at twenty-one. The increase in thickness of every bone depends upon a con- tinued secretion from the internal surface of the periosteum, at first soft and mucous, then osseous: when this secretion is ar- rested, the bones cease to grow in thickness, which commonly occurs some time after they have attained their full length. The changes which subsequently take place in them are those of interstitial deposite and absorption: the former is well exem- plified in inflammation of the bones, and in spina ventosa; the latter in the diminution of the bones in extreme old age, and in the loss of the alveolar processes. There is no period of life in which this interstitial absorption and deposite is not continually occurring, but it is much more rapid in young and growing animals than in the adult and old. The experiments of Mr. Hunter and of Duhamel, show, that 72 SKELETON. when a growing animal is fed upon madder, (rubia tinctorum,) the bones are quickly coloured by it; when the madder is with- held, the bones become again white; and that the first appear- ance of the restoration of the latter is manifested by a white la- mina being deposited on their surface. The madder, under such circumstances, is a long time in getting out of the bones. I fed a young pig for one month on it, mixed with other food. At the expiration of the succeeding five months, the animal, having grown very considerably, was killed. The interior la- minae of all the bones continued to be deeply tinged, while their surface from the depos'ite of new bone had become white. From this it would appear that deposite is a very permanent thing in bones: it, of course, must prevail much over absorption, else their growth would be arrested. At the same time that the periphery of each bone is increasing in its dimensions, the medullary canal is also augmenting: this arises from an absorption going on internally, while the depo- site is making externally. Duhamel* proved this by a curious experiment. He surrounded a cylindrical bone of a young animal with a metallic ring; on killing the animal some time af- terwards, he found the ring covered externally by a secretion of bone,t owing to the growth of the latter, and the medullary canal as large as the ring itself. Notwithstanding the obvious conclusion from this experiment, he made the mistake of sup- posing that the bone had enlarged by expansion, and not by a deposite externally with an absorption internally. As the individual advances in life, the cylindrical canal, in the centre of the long bones, continues to enlarge in size by the in- ternal absorption: so that the parietes of the bones, which in early life were much thicker than the canal, and in the adult about the same diameter, become exceedingly thin in old age; resembling thereby a stalk of Indian corn, with the pith scooped out.J The cells of the cellular structure in the several bones also enlarge, whereby the whole weight of the bones is much decreased in * Mem. de l'Acad. Roy. des Sciences, an. 1739-41-43-46. f If a string be tied around a growing tree, the same thing takes place, and it is finally shut up in the ligneous part. $ There are several examples of this in the Anatomical Museum. More rare- ly the reverse takes place, and the cavity is filled up: of this there are also spe- cimens. FORMATION OF CALLUS. 73 the very aged. In the parietes of the cranium there is rather a tendency to the absorption of the diploe, and the approximation of their tables. The bones, also, become more brittle in old age, in conse- quence of the increase of calcarious, with a diminution of ge- latinous matter. The reverse being the case in infancy, they are more flexible than in the adult, and can even bear to be twisted or bent without breaking. SECT. III.—ON THE FORMATION OF CALLUS. As this is a consequence of bones being fractured, and a mode that nature takes to repair the accident, there is some resem- blance between it and the primitive formation of bone. Owing to the rupture of the blood vessels of the bone, of the perios- teum, and of the medullary membrane, and frequently of the vessels of contiguous parts, the first effect of the accident is an effusion of blood into the cavity of the fracture. The several con- tiguous soft parts swell, become hardened and inflamed; and, in the mean time, an absorption of the blood is proceeding, while an effusion of coagulating lymph from the ruptured vessels occurs in the cavity of the fracture. A ring, the thickest part of which is precisely over the seat of the fracture, is formed by the lace- rated parts ossifying: they also form in the interior of the bone a sort of osseous pin. Till this moment the bone itself remains unchanged, with the exception of a coating of coagulating lymph on its broken faces; but now its extremities begin to coalesce or fuse themselves into each other, the superfluous bony matter (the ring and the pin) being no longer necessary, is absorbed, and the cavity of the bone with the membranes of the latter is re- established.* In this case it will be seen that the deposite of co- agulating lymph into the cavity of the fracture, corresponds with the mucous rudiments of the foetal bone, and that the re- maining phenomena of its ossification are the same. Some physiologists have attempted to give to the periosteum the exclusive credit of the formation of callus: the view is * J. Hunter, paper by Mr. Home, in Trans, of Society for Improvement. Lon- don, 1800. Vol. I.—10 74 SKELETON. erroneous, because experiments show, that even where the pe- riosteum is stripped designedly from the fractured ends of bones, they, nevertheless, unite, and the periosteum is restored when the callus is formed. The probability then is, that all the blood vessels (from whatever source they come) which penetrate the organized coagulating lymph secreted between the fractured extremities, convey and deposite calcarious matter. The celebrated Bichat and some others, were of opinion, that in every case of fracture where the ends of the bones are not kept in contact, granulations spring up from the ruptured sur- faces of the bone, and of its membranes; that these granula- tions first receive into their interstices a soft gelatinous depo- site, then a cartilaginous one, and, finally, a calcarious one, by which the bone is united. This process, however, is much more common in compound fractures which suppurate, and may be considered rare in simple ones. When the calcarious matter begins to take a place in a form- ing callus, if the part be much moyed, the process is arrested, the blood vessels no longer deposite even if they carry calca- rious materials, and an artificial joint is formed. The proper period of restoration being once passed, the vessels sink into an inactive state from which they have little or no disposition to rouse themselves. Under these circumstances, Dr. Physick proposed, many years ago, the introduction of a seton through the cavity of the fracture, and the retaining of it there for a long time, for the purpose of stimulating the vessels. The plan has now been repeatedly tried, with complete success, on the cylindrical bones, and, in one instance, upon the lower jaw.* Callus is formed much more speedily in young persons than in old: occasionally, however, we meet with cases in which the rapidity of its deposite in the latter is remarkable. I, for ex- ample, treated, in 1826, a female of ninety for a simple fracture of the os humeri, which was cured at the end of five weeks. * Dorsey's Elements of Surgery. Philadelphia Med. and Phys. Jour. &c. BOOK I. PART II. Of the Bones, individually. The several textures of the body are so interwoven, that the consideration of one alone, pursued through all its applications, excludes for the time, rather artificially, some one or more of the others. This circumstance, inseparable from a clear ac- count, has always perplexed writers on anatomy, and left them under various impressions concerning the best point of departure and method for pursuing their descriptions. Reasons of value may be urged for almost any arrangement: each one will have some peculiar advantages that the others have not, and which will cause it to appear to the understandings of its advocates, superior to the rest. For a course of study which is intended to be physiological and surgical in its combinations, the usual practice of beginning with the skeleton is, perhaps, the most advantageous; the young student will, however, understand that if the skeleton have any natural claim to this precedence, it is principally from its furnishing those land-marks, as it were, to which we refer the situation of other parts, and that it is only conceded, for the purpose of laying a foundation for their more easy and intelligible description subsequently. The human frame may be compared to an extended landscape, the multipli- city of whose features and the variety of objects spread over whose surface, collectively, bewilder the beholder; but by seizing first on its prominent outlines, marking the course of its mountains and ridges, and determining the bearings of the several objects according to them, we become able, at length, to define not only to ourselves, but to others, the precise position 76 SKELETON. of each point, or each object which may become the subject of inspection. Unfortunately, the minuteness with which the skeleton is de- scribed has been decried as useless, but the zealous and rea- sonable student ought to bear in mind—that the only rational plan of reducing a dislocated joint must depend upon a proper knowledge of its articular faces; that many of the great pheno- mena of life depend essentially upon the arrangement of the skeleton; that locomotion is inseparably connected with it; and that, in short, it has a bearing upon almost every animal opera- tion. With these facts impressed upon him, he wiU" be pre- pared to give the history of the natural skeleton a full and per- fect attention. CHAPTER I. THE TRUNK. The trunk is constituted by the Spine, the Thorax, and the Pelvis. SECT. I.--THE SPINE. The spine, (Columna Vertebralis, Rachis,) is placed at the posterior part of the trunk, and extends from the head to the inferior opening of the pelvis. It consists of twenty-eight or nine distinct pieces, of which the upper twenty-four are true, or moveable vertebrae. The twenty-fifth is the sacrum, or the pelvic vertebra, which is fixed; and the remainder are the cau- dal vertebrae or the coccyx. On the posterior face of the spine, each of the true vertebrae is seen to contribute, by a long process, to that ridge which is so readily felt beneath the skin, and from which, probably, the name of spine was derived. The spine increases gradually in size from the first to the last true vertebra. The upper part of the sacrum is extended laterally much beyond the latter, after- wards the spine diminishes abruptly to the extremity of the THE SPINE. 77 coccyx. The spine has several curvatures, which are best marked in the erect position. For example, the lower part of the cervical portion is convex anteriorly, and concave behind— the thoracic part is concave in front, and convex behind—the lumbar portion is convex in front, and concave behind—the pel- vic and caudal portion is concave in front, and convex behind. This arrangement is the result of the different degrees of thick- ness in the bodies of the vertebrae, and in the fibro-cartilages which unite them to each other. Wherever these cartilages are thin at their anterior margin, there is a concavity; but where they are thick at the same point, there is a convexity. There are seven vertebrae to the neck, called cervical; twelve to the thorax, called dorsal; and five to the loins, called lumbar. In reckoning the number of the vertebrae, the one next to the occiput is always the first; and so on, successively, to the last. Albinus, however, has departed from this rule, and counts them from below, upwards. General Character of a Vertebra. A vertebra (vertebre) consists in a body, in seven processes or extremities, and in a hollow for lodging the spinal marrow. The body of a vertebra is at its fore part; it is somewhat cy- lindroid or oval, but varies considerably from these figures ac- cording to its position in the spine. The anterior part of the body is convex; but the posterior part is concave, where it con- tributes to the spinal canal. The superior and inferior surfaces are flat, with the exception of a ridge of hard bone at the cir- cumference, more elevated, and not so extended in some bones as in others. These ridges are, in young subjects, epiphyses. There are many foramina, large and small, to be seen on the front and back surfaces of the bodies. They transmit arteries and veins, and some of them are used for fastening the liga- ments of the spine. On the posterior face there are two fora- mina larger than the others, occupied by veins coming from the interior of the vertebra. These veins correspond with the di- ploic sinuses in the head. They have been particularly de- 78 SKELETON. scribed by M. Breschet, of Paris, in a thesis presented to the School of Medicine in 1819. The processes are placed at the posterior part of the vertebra. Of these there are four oblique or articulating processes, which articulate with the corresponding ones of the bones, above and below; two transverse processes, which project, one on either side, from between the oblique processes; and one spinous pro- cess, which is placed on the middle of the bone behind. The two oblique, and the transverse process on each side, come from a common base or root that arises from the lateral posterior part of the body, and present collectively a very irregular appear- ance. Their faces and inclinations are much modified in the se- veral vertebrae. The spinous process is also much modified in regard to size, shape, and inclination. The body and processes form the periphery of the large fora- men for the spinal marrow, and, by their thickness and strength, afford an excellent protection to the latter. This foramen is of a triangular shape, presenting its base in front and its apex behind. It is always much larger than the spinal marrow, in- cluding its vessels, membranes, and the nerves that proceed from it; in which respect it differs very materially from the cavity of the cranium, where the latter is exactly filled by the brain. At the upper part of the spinal foramen of a vertebra, between the body and the upper articulating, or oblique process, is a groove. There is another groove between the lower oblique process and the body. These grooves, by the approximation of the contiguous vertebrae, are converted into perfect canals, called inter-vertebral foramina, for the transmission of the spinal nerves and blood vessels. The bodies of the vertebrae are extremely light and spongy, being formed principally of the cellular matter of bone, and are covered, with the exception of their upper and lower surfaces with a very thin lamella of bone. The processes, for the most part, have a thick and compact structure, enabling them to sus- tain conveniently the weight of the body and the action of the (different muscles, as applied to them. THE SPINE. 79 Of the Cervical Vertebrae, generally. The cervical vertebrae differ among themselves, but are dis- tinguished by certain common properties from the other bones of the spine. Their bodies and processes are small, but the spinal foramen is large, so as to admit of much motion, without pressing on the spinal marrow. The fore and back parts of the body are more flattened. The upper face is concave transverse- ly, being bounded on each side by a ridge of bone; the lower face is concave from before backwards, and is bounded by a ridge before and behind. This arrangement permits the bodies of adjoining vertebrae to embrace each other in the dried bones, and grants great facility of motion, in the living body, by the interposition of the inter-vertebral substance. The oblique processes have their articular faces at an angle of about forty-five degrees. The superior face upwards and backwards, the inferior downwards and forwards. The spinous process is short, triangular, nearly horizontal, and bifurcated at its posterior extremity, where it terminates in two tubercles. The transverse processes are short, and perforated by a large canal for the transmission of the vertebral artery and vein; they are concave above, somewhat convex below, and present two points at their external extremities for the origin and insertion of muscles. The inter-vertebral foramen is formed principally by the lower of the contiguous vertebrae. Of the Cervical Vertebrae, individually. The first cervical vertebra, commonly called the Atlas, from its supporting the head, presents the appearance of a large irre- gular ring, much thicker at its sides than elsewhere. It is en- tirely deficient in body, owing to the space allotted to that part in the other vertebrae being occupied by the processus dentatus '■ of the second vertebra. Its oblique processes are peculiar, both in shape an the linea ilio-pectinea that separates the greater from the lesser pelvis. The remaining third of the costa of the ilium is very rough and unequal, and is appropriated to the articulation with the sacrum, and to the origin of some of the muscles of the back. Immediately posterior to the sciatic notch is the surface for the sacrum, which is somewhat triangular, but irregularly so, and extends from the iliac fossa to the posterior inferior spinous process. Behind the sacral surface is another, twice as large, strongly marked by its roughness, and elevated into a vertical ridge at its middle. Anterior to this ridge arise many of the ligamentous fibres, fastening the ilium to the sacrum; but pos- terior to it is the surface of origin to the multifidus spinas, and the sacro-lumbalis muscles. Os Pubis, (Pubis.)—This bone constitutes the fore part of the innominatum, and is much the smallest of the three. It is composed by a body and two large branches from it, one run- ning downwards to join the ischium, and the other backwards and upwards to join the ilium. The body of the pubes is joined to its fellow on the opposite side by a flat surface, called the symphysis, which is eighteen or twenty lines in its long diameter. The superior part of the body also presents a flat surface, called its horizontal portion, which is bounded outwardly by a spinous process about an inch from the symphysis. The horizontal portion and the symphysis form a right angle. From the exterior face of the spine two ridges proceed outwardly; the posterior is the crista; it is sharp, elevated, and makes the anterior half of the linea ilio-pectinea; the anterior ridge is lower down, increases in its elevation as it goes along, is rounded, and runs nearly horizontally to termi- nate in the anterior upper margin of the acetabulum. Between the two ridges is a superficial triangular concavity occupied by the origin of the pectineus muscle; the base of the triangle is bounded by the protuberance formed at the junction of the pubes and ilium; and it is exactly over this part that the femoral vessels pass; its apex is the spine of the pubes. The extremity of the upper branch of the pubes is triangular, and much en- larged where it contributes to the acetabulum. Vol. I.—13 98 SKELETON. The inferior branch of the pubes, technically called its ramus, is a flattened process about an inch in length, and, as mentioned, descends to join the ischium. Its exterior is plain, and has no mark deserving of attention; but the internal face, near the an- terior margin, is concave for attaching the cms of the penis or of the clitoris. The body of the pubes in front is concave, and gives origin to the adductor longus and brevis muscles; behind, it is only sufficiently concave to participate in the general concavity of the pelvis. Os Ischium, (Ischion.)—This bone forms the posterior in- ferior portion of the os innominatum, and is the next in size to the ilium. It is of a triangular form, and has the anterior ex- tremity bent upwards to join with the pubes. The latter part is its crus or ramus, and the remainder is its body. The body of the ischium is a triangular pyramid, the internal side of which is smooth and uniform, but the posterior and the external sides are very unequal. The internal side is broad above and narrow below; at the middle of its posterior mar- gin is the spinous process, a projection of considerable magni- tude, and sharp-pointed, for attaching the lesser sacro-sciatic ligament. Immediately below the spinous process is a smooth concave surface, forming a trochlea, over which the obturator internus muscle plays. Below this trochlea, and forming the most inferior internal margin of the bone, is a long ridge, some- what more elevated behind than in front, into which the great sacro-sciatic ligament is inserted. The internal face of the is- chium, though technically called its plane, departs from the per- fect regularity implied in that name, by participating; in the ge- neral concavity of the pelvis. The posterior face of the ischium is swollen out, above, into a rounded surface, for the strengthening the posterior parietes of the acetabulum. This swell is bounded, below, by a trans- verse depression or fossa; immediately below which is the tu- berosity of the ischium, a large rough surface extending from the fossa to the beginning of the crus. This rough surface is subdivided into four, two above, and two below. The one above which is external, and nearest to the acetabulum, gives origin OSSA INNOMINATA. 99 lo the semi-membranosus muscle; the other, which is internal, gives origin to the semi-tendinosus, and to the long head of the biceps flexor cruris. Of the two flat surfaces below, the one which borders on the ridge for the insertion of the great sacro- soiatic ligament, is the part on which we sit, and the last sur- face, which is exterior again to this, gives origin to a part of the adductor magnus muscle. The exterior face of the ischium, above, forms the lower part of the acetabulum, and is, therefore, very much excavated; be- low this the surface is flat, and sufficiently uniform to dispense with a particular description. The crus of the ischium is flattened internally and external- ly, and in the adult it is fused completely into the crus of the pubes, so that very faint marks of their primitive separation are left. The anterior margin of the crus has, for the origin of the crus penis and the erector penis muscle, an excavation continu- ous with that on the crus of the pubes. In examining the general features of the os innominatum, it will be observed, that its outline is in some degree like the figure 8; the narrowing in its centre being produced by the sciatic notch below, and by the deep concavity above, between the an- terior superior spinous process and the symphysis of the pubes. The regularly rounded margin of the ilium above, and of the ischium below, contribute to the resemblance, but the angle of the pubes interrupts it. The narrowest part of the bone, or its neck, is between the top of the sciatic notch and the fossa below the anterior inferior spinous process. It will also be remarked, that the posterior margin of the sciatic notch is formed by the ilium, and the anterior by the ischium. The acetabulum, or the cotyloid cavity, (cavite cotyloide,) is placed immediately on the outside of the neck of the os inno- minatum. In infancy one-fifth of it is seen to be made by the pubes, two-fifths by the ilium, and two-fifths by the ischium. It is a very deep hemispherical depression, having a sharp ele- vated margin all around, particularly at its superior part. The inferior margin, amounting to one-eighth of the whole circum- ference, is comparatively shallow, and is, indeed, converted into a notch, sunk much below the general surface of the brim. The 100 SKELETON. greater part of the acetabulum is smooth, and incrusted with cartilage wherever the head of the os femoris is applied to the support of the trunk; but the very bottom, with the intervening surface continuous with the notch, amounting to rather more than one-fourth of the whole cavity, is rough, sunk below the general concavity, and is occupied by a soft vascular fat. In the fore part of the innominatum a large deficiency, called the thyroid foramen, (foramen thyroideum,) exists between the pubes and ischium. In the male subject it is triangular, with the angles rounded; but in the female it is rather oval. Leading from the plane of the ischium is a groove, which goes along the superior end of the foramen, and appears externally under the anterior ridge of the pubes. It conducts the obtura- tor vessels and nerve to the inner side of the thigh. The texture of the os innominatum is cellular internally, with a condensed lamella externally. It is of very various thickness. The ilium, in its centre, has the external and internal sides so near one another, that in most adults the light will shine through it. A large foramen is seen on the venter of the ilium, and another on its dorsum, for the transmission of nutritious arte- ries. There are several others, smaller, at various points of the os innominatum, for the same purpose, and for the adhesion of ligamentous fibres. SECT. V.—OF THE PELVIS, GENERALLY. The sacrum and coccyx behind, and the ossa innominata at the sides and in front, constitute, as observed, the whole cavity called pelvis, (bassin.) Its position is such, that, in the adult, it divides the entire length of the body into two parts nearly equal, the head and trunk forming one part, and the lower ex- tremities the other. Generally, the former are somewhat the longest; but in cases of unusual corporeal stature, the excess de- pends upon an undue length of the inferior extremities. On the contrary, in persons of little height, the latter have not been developed in proportion to the trunk of the body. - The pelvis, as a whole, is a conoidal cavity, having its base upwards, and the submit below. Its internal surface forms an irregular floor, on which the viscera of the abdomen are sus- THE PELVIS. 101 tained in the erect position; and its external surface, by project- ing considerably at various places, establishes very favourable points for the origin of muscles. The internal surface of the pelvis is divided by the projection of the anterior margin of the base of the sacrum, and by the li- nea ilio-pectinea, into two cavities; the upper one is the great pelvis, and the lower one, the little pelvis. The great pelvis is the base of the cone, and presents at its anterior part a large de- ficiency, which is supplied in the fresh subject by the abdominal muscles. The little pelvis is a complete bony canal, much deeper behind and at the sides, than in front. Its depth, behind, is formed by the whole length of the sacrum and coccyx; at the sides, by the bodies of the ischia and a small part of the ilia; and, in front, only by the length of the bodies of the pubes. The upper orifice of the lesser pelvis is called its superior strait: it is somewhat oval, and looks obliquely forwards and upwards. Its axis may be indicated by a line drawn from the extremity of the coccyx to a point an inch, or thereabouts, be- low the umbilicus. The inferior orifice of the lesser pelvis is called the inferior strait. Its margins in the naked skeleton are very unequal, for it presents three very deep notches, two late- rally, and one in front. The first are formed by the external margins of the sacrum and coccyx, contributing to deepen the sciatic notch, which already is formed in each os innominatum. The third one is formed by the convergence of the rami of the pubes and ischia of the opposite sides, and constitutes the arch of the pelvis of authors, sometimes called the arch of the pubes. The axis of the lower strait, it is clear, must have a very different direction from the axis of the superior, and is indicated by a line drawn from the lower part of the first bone of the sacrum, through the centre of this opening. The cavity of the lesser pelvis is.increased considerably behind, by the curvature of the sacrum; this, however, is not uniform, as the sacrum is much more curved, as well as longer in some indi- viduals than in others. The planes of the ischia are not paral- lel with one another, but converge slightly from above, in con- sequence of which the transverse diameter of the lower strait is rather smaller than the transverse diameter of the superior strait. 102 SKELETON. Difference of the Pelvis in the Male arid Female. There are several well marked peculiarities in the fully deve- loped pelvis of either sex. The ossa ilia are larger, less concave, and more horizontal in the female. The superior strait is also larger, and more round: its transverse diameter always exceeds the antero-posterior; whereas, the latter, in the male, frequently is found the longest. The lesser pelvis is also more capacious in women. The crura of the pubes and ischia, are not so long as in men; but they di- verge more, and join at the under part of the symphysis pubis by a large, regularly rounded arch: whereas, in men, the arch, as it is called, is merely an acute angle. The os sacrum in women is shorter, more concave, and is also broader in proportion to its length. The spaces, vertically, be- tween its foramina in front are very small, forming a sort of ridges, which give to the bone the appearance of having been compressed in its length. The distance between the upper and lower straits, or, in other words, the depth of the small pelvis in women, is not so great as in men: this arises from a comparative shortness in the bo- dies of the pubes, of the ischia, and of the sacrum, as just men- tioned. The cartilaginous joining of the pubes is thicker in women. The diameters of the inferior strait, like those of the superior, are longer in females. Accoucheurs have attached much importance to the direction and length of the diameters of the small pelvis in well formed women. At an average they are as follow. The superior strait presents three diameters: The first or antero-posterior extends from the upper extremity of the symphysis pubis, to the mid- dle of the projection of the sacrum at its superior margin, and measures four inches: The second diameter, or the transverse crosses the first at right angles, and extends from the middle of one side of the strait to the corresponding point on the other- it measures five inches: The oblique diameter extends from the sacro-iliac junction of one side to the linea ilio-pectinea over the acetabulum of the other, and measures four inches and a half, sometimes more.* * See Dewees' System of Midwifery, 7th edition, 1835, p. 28. THE PELVIS. 103 At the inferior strait, the antero-posterior diameter is drawn from the lower part of the symphysis pubis to the lower end of the sacrum, and measures five inches.* As the coccyx, in child-bearing women, is moveable, its projection forwards is not taken into the account, because it recedes by the pressure of the child's head, and does not resist its passage: in some cases, how- ever, it is unfortunately fused into the sacrum, and therefore perfectly rigid, which will diminish this diameter at least an inch. The transverse diameter of the inferior strait is drawn from the middle of the internal margin of the tuberosity of one ischium, to the corresponding point on the other, and measures four inches. The depth of the little pelvis, in the female, at the symphysis pubis, is an inch and a half: at the posterior part four inches, or five if we include the coccyx; and at the side three inches and a half. There are many other details connected with the measurements of the pelvis, which are mentioned by systema- tic writers on midwifery. SECT. VI.--DEVELOPMENT OF THE PELVIS. Three points of ossification are observable in the os innomi- natum of the early foetus: one is at the superior part of the ilium, another is at the tuberosity of the ischium, and the third is at the angle of the pubes. The radii of ossification from these centres, have extended themselves considerably at birth, so as to sketch out the forms of the bones to which they respectively belong. But these bones are separated from one another by cartilage, and do not coalesce till years afterwards. The union or fusion of the ilium and pubes then occurs.at the ilio-pecti- neal eminence, over the acetabulum, and partly in this cavity; the ilium and ischium join in the acetabulum principally, and the ischium and pubes unite by their respective crura at the middle of the internal side of the foramen ovale. All the points of the os innominatum, most remote from the primitive centres of ossification, are cartilaginous at birth: as, for example, the crest, the spinous processes, the tuberosity, and even the com- ponent parts of the acetabulum. The latter cavity has then a * Dr. Dewees says four. Loc. cit. 104 SKELETON. triangular shape, and from its very flexible and yielding condi- tion, is incapable of afford ing^ a strong point of support to the trunk in the erect position. At the birth, the middle parts of the os sacrum, which are employed in protecting the spinal marrow, are more advanced in their ossification than its lateral parts. The five pieces which compose it, are, like the bodies of the true "vertebrae, of a rounded shape. The processes behind are cartilaginous. The coccyx is extremely small and scarcely presents any ossification what- ever. The pelvis of the foetus, at birth, is smaller in proportion than the superior portions of the trunk; this is one of the reasons why the abdomen is so projecting. The lesser pelvis is so small and shallow, that the bladder, even in the undistended state, cannot be accommodated by it, but is contained principally by the abdomen. Its transverse diameter is much shorter than the the others. The superior strait faces much more forwards than / in the adult. SECT. VII.--ON THE MECHANISM OF THE PELVIS. The pelvis has an important part in the several actions of standing and of locomotion; besides its usefulness in giving a support to the viscera of the abdomen, and in having attached to, and contained within it, the organs of generation. In standing, the pelvis is impelled by two opposing forces, in consequence of the attachment of the vertebral column at its hind part, and of the ossa femorum at its anterior lateral parts. The weight of the head and of the upper parts of the body, falling upon the sacrum, acts upon a lever, which is represent- ed by the distance between the acetabula and the sacro-iliac junction, and has a tendency to depress the posterior part of the pelvis, by rotating it upon the heads of the thigh bones. This movement is obviated by the iliacus internus, psoas magnus, and some other muscles, which keep the front of the pelvis from rising up. It is also prevented by the principal weight of the trunk being in front of the spine, and therefore inclining forwards, so that the centre of gravity, in the erect position, gives a continual tendency to fall forwards instead of back- wards. THE THORAX. 105 The wedge-like shape of the sacrum is highly favourable to the erect position: from having its base upwards, whenever the weight of the trunk is thrown upon it, it is driven down be- tween the ossa innominata, and has the tightness of its articular connexion, therefore, much increased by the position which it is intended to sustain. In illustration of the usefulness of the triangular or wedge-like shape of the sacrum, it may be ob- served, that it is much less so in animals which are intended to go upon all fours than in the human subject. The articulation of the several bones of the pelvis with each other, is so close as not to admit of any motion between them, with the exception of the os coccygis, and of the relaxation pe- culiar to pregnancy. The pelvis, however, has upon the spine, flexion, extension, lateral inclination, and rotation; the latter being performed by a series of very slight twists of the lumbar vertebrae upon each other. Like all other motions, it is much extended by habit in early life. Of this I have seen an instance, in an adult Indian, who, from infancy, had been deprived en- tirely of the use of the lower extremities; but who, by being seated in a large wooden bowl, with a round bottom, and having his legs drawn up in a squatting position, could, by alternate twists of the spine, with the assistance of a short staff in each hand, move with surprising speed over a plain surface. SECT. VIII.--OF THE THORAX. The thorax is the upper part of the triink, and is formed by the dorsal vertebrae behind, by the sternum in front, and by the ribs with their cartilages at the intermediate spaces. It is of a conoidal figure, flattened in front, somewhat concave behind, and semi-cylindrical on the sides. The interior circumference corresponds with the exterior, with the exception of the poste- rior part, where, owing to the projection of the column of dor- sal vertebrae, a partial septum exists which has a tendency to divide it into two cavities. The superior part of the cone, or its summit, is much smaller than the inferior part or the base, and presents a very oblique cordiform foramen, much lower in front than behind, owing to the superior margin of the sternum being lower than the first dorsal vertebra. The base of the Vol. I.—14 106 SKELETON. thorax is a very large opening: its lateral and posterior mar- gins, formed by the ribs and their cartilages, present a convex- ity downwards; but, in front, where the latter run up to join the sternum, a large notch is formed between the cartilages of the opposite sides, into the apex of which notch the third bone of the sternum projects. Of the Ribs. The ribs, costae, (cotes,) are twenty-four in number, twelve on either side. Of the latter, the upper seven, in consequence of their cartilages joining the sternum, are called the sternal or true ribs, and the lower five, from their cartilages stopping short of the sternum, are called the false or asternal ribs. Cases are recorded by several anatomists of there being eleven or thirteen ribs on a side: the latter I have seen several times, and the for- mer but once or twice. In such cases, the dorsal vertebrae cor- respond in number with the ribs. In the instances of redun- dance which have come under my notice, the last rib looked like a transverse process of unusual length, belonging to a lum- bar vertebra. The superabundant vertebra constituted the thir- teenth dorsal; but was formed like the first lumbar as it com- monly exists, and the last lumbar vertebra was entirely anoma- lous in its shape, being intermediate in form to a lumbar verte- bra, and to the first bone of the sacrum. All of the ribs are so placed, that they run very obliquely downwards and forwards from their posterior extremities. This obliquity becomes the more striking as the ribs increase suc- cessively in length. The first rib, for example, articulating by its posterior extremity with the first vertebra of the back, has its anterior extremity nearly on a horizontal line with the lower part of the third dorsal vertebra. The seventh rib has its anterior extremity on a horizontal line with the lower mar- gin of the last dorsal vertebra, notwithstanding its posterior extremity articulates with the seventh vertebra. The same sort of comparison might be usefully instituted in regard to all the ribs, in which case the rule will be found closely applicable, with the slight exception of the two or three last ribs. The ribs are nearly parallel to each other in this obliquity, allowance THE THORAX. 107 being made for the effect which the obliquity of the sternum has in causing a greater separation of their anterior extremities from each other, than exists at their posterior extremities. Common points of resemblance between the Ribs.—Each rib is paraboloid; presents an external and an internal surface; an upper and a lower margin; a sternal and a vertebral ex- tremity. The external surface of each rib is convex, while its internal surface is concave. The former presents, not far from the ver- tebral extremity, an oblique ridge, occasioned by the insertion of the sacro-lumbalis muscle. It is precisely at this line that a curvature, somewhat abrupt, takes place, which is the angle of the rib. Between the angle and the transverse process of the vertebra, each rib is rather more narrow and cylindrical than it is in advance of the angle. The superior margin of the rib is rounded and somewhat rough, for the insertion of the intercostal muscles, while the inferior margin is brought to a thin, cutting edge. Just within, and above the latter, is a fossa beginning somewhat nearer to the spine than the angle of the rib, and ceasing about one-third of the whole length of the rib, short of its anterior extremity. It contains the intercostal vessels and nerve. From the upper margin of this fossa arises the internal intercostal muscle, and from the lower the external. The anterior extremities of the ribs are thin and flattened, in the upper eight there is some increase in their breadth at this point, and in all there is an oblong pit for receiving the end of the corresponding cartilage. The vertebral extremity of the rib is its head, and presents two flat articular surfaces, separated by a ridge. This head is received into the inter-vertebral mat- ter, and upon the articular faces of the adjoining margins of the vertebrae. A small depression exists upon the posterior face of the rib bordering on its head, for containing a little fatty mass. About an inch beyond the head, at the posterior under surface of the rib, is a tubercle, presenting a smooth articular face, for connecting itself with the transverse process of the vertebra. Just beyond this, but bordering on it, is a much smaller tuber- cle, not unfrequently indistinct, for the insertion of the exter- 108 SKELETON. nal transvere ligament, and below it is a small pit for the lodge- ment of fatty matter near the joint. The space between the greater tubercle and the head of the rib is its neck, which is in contact with the antero-superior face of the transverse process of a vertebra, and has a sharp ridge on its upper margin, for the insertion of the internal transverse ligament. The most of the ribs have a very sensible twist in them, by which their spinal extremity is directed upwards, and the ster- nal extremity downwards; from which it results, that the whole length of the rib cannot be brought into contact with a hori- zontal plane. Differences in Ribs.—Though there are many common points of resemblance among the ribs, yet there are, also, some well marked peculiarities. The ribs increase successively in length from the first to the seventh, inclusively; they then decrease: the last is not only the smallest, but not unfrequently the shortest. The angles of the ribs increase in their distance from the spine, from the first to the last rib. The angle, however, of the first rib, is not well marked, from its being so near the tubercle; neither is the angle of the last, from its being so near the ante- rior extremity. The oblique ridges constituting or marking off the angles, are placed one above the other, in the same line. This gives to the back of the thorax a triangular flatness, the base of which is below. The projection backwards of the angles of the ribs, along with that of the spinous processes of the ver- tebrae, forms on each side of the latter a gutter, which is filled up by the large muscles that keep the trunk erect. This gutter is, of course, broader below. The first rib is more circular than the others. Its head is spherical, instead of presenting two articular surfaces. This rib is fiat above and below; its margins are internal and exter- nal. It has no intercostal groove. About the middle, the up- per surface is marked by a superficial oblique fossa, made by the subclavian artery; in front of, and behjnd which is a small rising, marking the insertion of the scaleni muscles. The se- cond rib is considerably longer than the first, and has its flat surfaces obliquely Upwards and downwards, so as to round off that part of the thorax. The four inferior ribs decrease at their THE THORAX. 109 anterior extremities, or become somewhat tapering. The two last ribs do not articulate with the transverse processes, and, consequently, have no corresponding tubercles. As their heads articulate with the middle of the bodies of their respective ver- tebrae, instead of with the margins, they present only a single and somewhat spherical surface. The eleventh rib is marked only for a short distance in its middle by the fossa, for the in- tercostal vessels. The twelfth rib has no mark of the kind. There is an augmentation in volume from the second to the eighth rib, inclusively; afterwards they decrease. The angles of the ribs are, successively, more and more obtuse. The structure of the rib is spongy, covered with a lamella of compact bone. The spongy structure predominates at the an- terior extremity, for there the rib is comparatively soft. Of the Sternum. This bone constitutes the middle front part of the thorax, and, owing to the obliquity of the ribs, has its superior end on a horizontal line with the third vertebra of the back, while its inferior extremity is on a horizontal line with the eleventh dor- sal vertebra. It is also placed in a slanting direction, so that the lower part recedes from the spine much farther than the upper. The sternum is oblong, somewhat curved, like a bow, so as to be convex in front, and concave behind. It is divided, in the adult, into three distinct pieces; an upper, middle, and lower, which are held together by cartilage and by ligament; but not unfrequently in advanced life these pieces are all fused into one, by bony union. The first and middle parts join where the second rib is articulated, and the middle and lower where the seventh rib articulates. At these points there is a well marked transverse ridge, both anteriorly and posteriorly, and between them, on the front of the bone, there are other ridges not so strong, indicating the original separation of the bone into several other distinct pieces. The lateral margins of the ster- num are somewhat elevated where the ribs articulate. The upper end of the sternum is both thicker and broader \]Q SKELETON, than the lower end. Where the first and second parts join, there is a narrowing of the two: the same occurs where the se- cond and third pieces unite. The first, or upper bone of the sternum, has an irregular square figure; it projects somewhat above, and is slightly hol- low below. It is scooped out at the superior margin, and pre- sents a point at each end of the scoop. At the side of the lat- ter is a concave and rounded surface for articulating with the clavicle; just below which is a rough surface, for the cartilage of the first rib. The bone diminishes much in breadth from this point, and terminates by a narrow oblong face, joining it to the second piece. At each side of this junction both pieces con- tribute to a fossa for the cartilage of the second rib. The second bone of the sternum is longer and narrower than the first. At its lower part it increases somewhat in breadth, and then terminates by being rounded off on either side, so that its margins converge towards each other. The sides of this piece afford complete pits for the third, fourth, fifth, and sixth ribs; the pit for the seventh is common to it and the third bone, as the pit for the second rib is common to it and the first bone. The sixth and seventh pits are in contact, the fifth is very near the sixth, the fourth is about half an inch above the fifth. On viewing the whole side of the sternum, it will be observed that the distances between the pits decrease, successively, from the first to the last. The third bone of the sternum, in the young adult, is fre- quently in a great degree or wholly cartilaginous, hence, the name of xyphoid cartilage (cartilago xyphoides or ensiformis) has been applied to it. It is thin, varies remarkably in its breadth in different individuals, and has the lower extremity sometimes turned forwards and sometimes backwards, but most frequently it is inclined only slightly forwards. The base of this piece presents a narrow oblong surface for articulating with the second bone, at each end of which is the half fossa for the seventh rib. The margins of the ensiform cartilage are thin, and have the transverse muscles of the abdomen inserted into CARTILAGES OF THE RIBS. Ill them. Sometimes the lower extremity, instead of being point- ed, is bifurcated. The sternum is composed of a spongy texture, enveloped by a thin layer of compact substance. Its strength depends, in a great degree, on its ligamentous covering. SECT. IX.--OF THE CARTILAGES OF THE RIBS. These are placed at the anterior extremities of all the ribs, the seven superior of which they unite to the sternum by the sychondrosis articulation. The length, breadth, and direction of these cartilages are far from being uniform. The first costal cartilage is short; the following ones increase in length, successively, to the seventh, inclusively. The carti- lages of the false or abdominal decrease, successively, in length from the eighth to the twelfth, inclusively; the last is a mere tip to the end of the rib. The breadth of the first cartilage is considerable near the sternum; the succeeding ones are not so large at this point. With the exception of the three first, the costal extremities of the cartilages are larger than the sternal; and they become more rounded as they advance to the latter. The cartilages, in point of magnitude, generally, will be found in proportion to the size of the ribs with which they articulate. The sixth and seventh are joined together, and are spread out at their middle, which gives there an increase of breadth, and permits them to touch, and sometimes to coalesce. The first cartilage goes obliquely downwards in the direction of the rib to which it belongs, in order to join the sternum. The second and the third cartilages are nearly horizontal, but inclining a little upwards in their progress; the fourth, fifth, sixth, and seventh, pass, successively, more and more obliquely upwards to the sternum, in consequence of the increasing length of the ribs requiring them to traverse a longer space to reach this bone. From the direction of the cartilages being oblique- ly upwards, while that of the ribs is.obliquely downwards, the angle formed near the rib at the base of the cartilage, where the latter begins first to turn upwards, is less obtuse in the lower cartilages than in the upper. The obliquity of these cartilages 112 SKELETON. is also very manifest, by comparing them with the side of the sternum: with it they form a very acute angle below, and a very obtuse one above. The cartilages of the false ribs, successively, decrease in length, to terminate in front by small tapering extremities. The first is united by ligaments, somewhat closely, to the last true or sternal, and is occasionally sent forwards fully to the sternum. The others are united more loosely, in such a way that the anterior extremity of the one lies against the inferior margin of that which is above. The eleventh and twelfth car- tilages are generally too short to touch the ones above, they therefore are fixed principally by their connexion with the ab- dominal muscles. Their ribs are much more moveable than any others, and have been called floating, from that cause. There is some difference between the two extremities of the cartilages; the posterior or costal is a small, convex, unequal surface, very closely united to the anterior extremity of the cor- responding rib. The other or sternal extremity in the sternal cartilages, offers a smooth articular face, which is angular or convex, according to the shape of the cavity in the sternum with which it has to articulate. The three first abdominal, and the last sternal cartilage, make, to the lower part of the thorax, a broad and well marked margin, convex in front and concave behind. The cartilages of the ribs are, in persons of middle age, white, flexible, and very elastic. They are dissolved very slowly in boiling water; by which they, if young, are reduced to gelatine, otherwise their solubility is very imperfect. They have a structure differing, in some respects, from other cartilages; when dried, and exposed to the action of the 'atmosphere, they are seen to consist of an immense number of small thin plates, plated end to end, and separated by deep fissures. M. Herissant de- scribes these plates as interlaced one with another, and forming a kind of spiral, the regularity of which is interrupted by small cartilaginous projections, uniting the plates to each other.* These cartilages have a great disposition to ossify, which is ma- nifested in most individuals somewhat advanced in life. The ossification begins in their centre, and advances to the circum- • Acad, des Sciences, an. 1748. DEVELOPMENT OF THE THORAX. 113 ference, and is always preceded by a yellowish tinge. When they are fully ossified, like the ribs, they are cellular within, and compact externally, and are continuous with the ribs, there being no interval: in such cases, the distinction from the ster- num is generally kept up, with the exception of the first, which is fused into it. The complete ossification of the first cartilage is not uncommon; the others, though there is generally in old persons a considerable deposite of bone in them, are seldom fully ossified. In neither case, however, is it common to see such a perfect continuity of bone between the rib and sternum, that the junction may not be dissolved at one point or another by the action of boiling water: at least, after very numerous ob- servations on this subject, I do not remember to have met with a single instance of it. SECT. XI.--OF THE DEVELOPMENT OF THE THORAX. In the foetus the shape of the thorax differs much from that of the adult, in the greater comparative extent of its antero-pos- terior diameter, and in the projection of the sternum. The state of the thoracic viscera, at this period, calls for such an arrange- ment; as the heart and thymus gland, which are in the middle, have a considerable extent, whereas, the lungs are still collapsed from the emptiness of their air cells. The ribs are but little curved at their posterior parts, the angle being by no means well formed, in consequence of which, the fossa on each side of the bodies of the vertebrae, in the thorax, is not so deep; neither is the fossa behind, on each side of the spinous processes, so fully marked. The superior opening of the thorax is more round from the increase of the antero-posterior diameter. The inferior opening is extremely large, both from the elevation of the sternum, and from the pressure of the abdominal viscera, of which the liver, from its great extent, is a principal agent. The vertical diameter of the thorax is small, from the ribs, particu- larly the lower ones, being pressed up one against the other, by the diaphragm, acted on by the abdominal viscera. The bones individually are in the following state at birth. The ribs are almost completed, the heads, where they join the Vol. I.—15 114 SKELETON. spine, being in a state nearly as perfect as at any subsequent pe- riod of life, and not by any means in the condition of a cartila- ginous epiphysis, as is presented in the extremities of the cy- lindrical bones generally. These bones, as Bichat very justly observes, are destined to a function which commences imme- diately upon birth, and which requires in them as much perfec- tion then, as they have in the adult. For respiration is different from locomotion, the latter requires a species of education, which may be given gradually, whereas one respires from the begin- ning as he will respire always. The sternum, which is less im- mediately connected with breathing, and only contributes to the general solidity of the thorax by completing its circumfe- rence, is in a state almost cartilaginous, and presents only nuclei * of ossification in its several pieces. At the instant of birth, a great change is produced in the di- mensions of the thorax. The lungs, from being in a collapsed and solid state, suddenly suffer an expansion of their cells by the introduction of air into them, and increase twice or three times in magnitude. This is accomplished by the elevation of the ribs, and the consequent increase in the transverse dia- meter of the thorax: it becomes a condition that for ever after- wards remains, so that the lungs, even upon death, continue to have their air cells distended, and do not return to a perfectly collapsed state. The action of the diaphragm is but small in the earliest periods of life, owing to the size and pressure of the ahdominal viscera against it; respiration is then principally car- ried on by the elevation and depression of the ribs, and by their being rolled outwards, a motion which the flexibility of their cartilages and the looseness of their articulating surfaces favour very much. At the age of puberty the thorax experiences a remarkable augmentation. Its transverse diameter is insensibly increased, and there is a general expansion of its volume, indicative of a healthy and vigorous constitution. Should this not take place, and the sternum be projected, it is supposed to mark a disposi- tion to consumption. The enlargement of the thorax is un- doubtedly also connected with a development of the organs of generation at the same time. The exercise of the latter re- quires greater vital powers than exist in early life, and the pro- MECHANISM OF THE THORAX. 115 vision for it is manifested by the general increase of vigour and firmness in the human frame; but it is not possible to point out in what manner the sympathy exists, which, on the develop- ment of the organs of generation, extends their influence to the bony structure of the thorax. SECT. XI.--OF THE MECHANISM OF THE THORAX. The thorax performs two very important offices in the ani- mal machine: the first is to contain and protect the organs of circulation and respiration, the second to assist in the function 0 of respiration, and perhaps that of circulation.* The mechanism of the thorax is such that the solidity of its materials, and its rounded shape, present a very efficacious de- fence to its viscera from the influence of blows on its outside. The effects of the latter are also materially diminished by the thickness and contraction of the several large muscles which are placed on its surface. On its back part the thick longitudinal muscles of the spine, as well as those running to the superior extremities, fill up the gutters on each side of the spinous pro- cesses, and make a fleshy protuberance, divided into two by the raphe which extends the length of the back over the spinous processes. In front it is less protected, owing to the sternum being immediately under the skin. Nevertheless, when blows are inflicted on this part, their effects are much diminished by the elasticity of the cartilages of the ribs, and by the direction, obliquely downwards, of the ribs themselves; both of which dispose the sternum to retreat backwards, and to yield to the impelling force. The recession will take place more readily at the moment of expiration: and when the muscles which elevate the ribs are not on their guard. In those deliberate exertions of the streugth of the thorax, exhibited by individuals lying down on their backs, and sustaining a heavy weight on the ster- num, the ribs are saved from injury by different means. The arched form, itself, of the front of the thorax, is of considerable service in the resistance under such circumstances; this, how- * A very interesting paper, on this subject, has lately been presented to the French Institute by M. Barry. 116 SKELETON. ever, would be easily overcome, and the ribs would break, if the arch were not sustained in its elevation by the contraction of the large muscles on its sides; as the serratus major, the pec- toralis major and minor, each of which, by acting on the de- pressed anterior extremities of the ribs and their cartilages, has a tendency to keep them elevated. Fractures of the ribs, from blows or force applied in front, are not so liable to occur in the part stricken as in the point feeling the greatest momentum, which from the semicircular form of the ribs is in or near their middle: this exhibits a true example of what the French writers call the contre-coup. Bichat says, that the fracture by contre- coup is much more common when the individual being struck unexpectedly, has not had time to throw his muscles into a state of contraction, for the protection of the ribs. The lateral convexity of the thorax being greater than that in front or behind, and having the same assistance from the muscles mentioned, presents a stronger resistance when blows are inflicted directly on it. Each rib represents an arch, the summit of which is its centre, and the base its two extremities. The abutments of the base are, the sternum at one end and the spine at the other; a displacement from them is completely pre- vented by the strength of the ligamentous attachments, as well as by the form of the surfaces. Under these circumstances, as fracture occurs preferably to dislocation, it is generally at the point stricken. The abdominal or false ribs, from their want of attachment to the sternum, present a very different condition. Their an- terior extremities, therefore, yield readily, and are driven inwards towards the abdomen. The second function of the thorax, relating to its influence on respiration, is executed by its dilating and contracting, whereby the air is received into, and expelled from it. The spine is the fixed point for the motions of the ribs in respiration. In the act of dilatation, the capacity of the thorax is augmented in three directions, vertically, transversely, and antero-posteriorly, or from the sternum to the spine. The vertical augmentation is accom- plished by the diaphragm; and, as mentioned, is much greater MECHANISM OF THE THORAX. 117 proportionally in the adult than in the infant, from the greater comparative size of the abdominal viscera in the latter. The transverse augmentation is produced by the successive contrac- tion of the intercostal muscles, which raise the ribs upwards. The first rib is moved inconsiderably, in consequence of its short- ness and of its continuity with the sternum. The attachment of the scaleni muscles to its upper surface, serves rather to give a fixation to it, and to prevent it from being drawn down by the other ribs, than to produce by their contraction an elevation of it. The first rib may, therefore, be considered as a fixed point. The first intercostal muscles contracting from it, draw up the second rib, which in its turn, becoming a fixed point for the second intercostal mucles, they contract and draw up the third rib, and so on successively to the last. It is the obliquity of the ribs from behind, downwards and forwards, which enables this elevation of them to produce an increase in the lateral diameter of the thorax: without such obliquity, their elevation could not produce the effect. The obliquity, however, alone could be of but little ser- vice, if the anterior extremities of the ribs were not attached to the sternum by cartilages, which have to ascend in order to reach it; for it is obvious that the angle of the cartilage and rib, during their elevation by the intercostal muscles, has a tendency to en- large itself; and will, in doing so, increase the horizontal distance between the anterior end of the rib and the sternum, and con- sequently increase the transverse diameter of the thorax. The upper ribs, from the shortness as well as direction of their car- tilages, can do little or nothing in increasing this diameter. According to some anatomists, the capacity of the thorax is also augmented by a rocking motion of the rib, in which, the two extremities being stationary, the middle is drawn upward and outward. It is not, however, very clear, that this motion exists to much extent, in the adult, as the posterior articulations of the thorax are opposed to it. While the transverse enlargement of the thorax is going on, a simultaneous motion occurs in the sternum, and in consequence of the oblique direction in which the ribs run to it, the ster- num is caused, by the elevation of their bodies, to recede from the spine. But, as the ribs increase successively in length 118 SKELETON. from the first to the seventh, each lower one, in its elevation from the oblique towards the horizontal line, has its anterior extremity carried proportionably farther off from the spine; hence, the sternum has a combined movement resulting from its several attachments to the ribs: one motion elevates it as a whole, another causes it to recede from the spine as a whole: and the third causes its lower end, from the increased length of the ribs there, to be pushed farther from the spine than the up- per; giving it, thereby, during respiration, a slight motion back- wards and forwards, resembling that of a pendulum. This lat- ter motion, however, though its existence is clear, is not very considerable, from the sternum being kept in check by the ten- dinous centre of the diaphragm, as one may prove by examining his own body. The enlargement of the thorax, in its antero- posterior diameter, is much more considerable at the anterior extremities of the ribs, because there they are comparatively free. In this case, the cartilages of the ribs are bent forwards, besides being elevated. In expiration, the movements of the thorax are exactly the reverse of what they are in inspiration, and all its diameters are, consequently, diminished. Whatever may be said of muscular influence in producing this change, it is much exaggerated. It is true, that there are certain muscles which may be applied to this end, as the abdominal, and also some on the back, as the longissimi dorsi and sacro lumbales; but that they are actually so engaged, under ordinary circumstances, is rather questionable. In observing the phenomena of natural respiration, when, by position, all these muscles are put into a state of relaxation, it does not appear that the process is at all impaired by their be- ing thrown out of action. The only muscles, therefore, that seem to be especially appropriated to produce expiration, are few and small: they are the serrati inferiores postici, one on either side of the spine. But, when the lower ribs are fixed by the several muscles inserted into them, they become points of support to the upper ones; and then the intercostal muscles may officiate in expiration, by drawing the ribs successively down- wards, as they do, in inspiration, by drawing the ribs succes- sively upwards. MECHANISM OF THE THORAX. Hg The elasticity of the cartilages, by which these bodies are en- abled to return from the constrained state in which they were placed by inspiration, has also been supposed important to ex- piration, by Haller, and others. The power thus derived is certainly of some value; but has much less than has been at- tached to it. It unquestionably exists in early and middle life, but is lost in old age, when the cartilages ossify, and, therefore, are deprived of elasticity. The true and efficient cause of expi- ration appears to be atmospheric pressure, upon the external parietes of the thorax, acting along with the natural elasticity of the lungs. The lungs, it is well known, when in a state of repose, and removed from the thorax, are much smaller than the cavities which they fill during life. They have, therefore, a continual disposition, in the living state, to return to the size which is most easy to them; and, when they are dilated by inspiration, they subsequently contract. These positions are proved conclusively, by the condition of the inferior surface of the diaphragm, in a healthy and entire thorax; where this mus- cle, in consequence of atmospheric pressure from without, is driven high up into its cavity. Its contraction in inspiration draws it down, and the instant that the contraction ceases, it is impelled upwards again. Now, the same power is applied to the whole periphery of the thorax: and its cavity being en- larged by the contraction of the several muscles appropriated to the elevation of the ribs; the moment this contraction ceases, the latter are impelled downwards. From all this it will be un- derstood that the muscles, by creating a vacuum in the lungs, cause the vacuum to be filled by the introduction of air through the trachea; and upon their ceasing to contract, the several agents mentioned cause the expulsion of the same air. It is ge- nerally believed, that the surface of the lung is every where in contact with the thorax; it appears, however, doubtful, whether there is not a space between the pleura pulmonalis and diaphrag- malis, particularly at the most posterior and inferior part of the diaphragm. Certain it is, that adhesions there are much less common than in other parts of the thorax. The ligaments at the spinal extremities of the ribs, by being put on the stretch in inspiration, have also some tendency to throw down the ribs in expiration. In short, the contraction 120 SKELETON. of the thorax may be set down as the result of the joint action of the atmosphere, the cartilages of the ribs, the ligaments, the contraction of the lungs, and the muscles. When the structure of the lung is so altered that its elasticity is impaired or de- stroyed, expiration becomes then much more difficult. CHAPTER II. OF THE HEAD. The head is placed upon the upper extremity of the verte- bral column, and consists in a considerable number of bones, which are either in pairs, or, if single, have the two sides sym- metrical. Some of these bones form a large cavity, the cranium, for containing the brain; the others are employed in the forma- tion of the nose; of the orbit for the eye-ball; and of the mouth. The head, for the most part ovoidal, presents very striking^ va- rieties of form between different individuals and different nations. It is thought by physiologists, that the moral or intellectual con- dition of a people, their habits, climate, and food, have a power- ful influence in producing these diversities. The head is divided into cranium and face. SECT. I.—OF THE CRANIUM. The Cranium is composed of eight bones. The Os Frontis, the Os Occipitis, two Ossa Parietalia, two Ossa Temporum, the Os Sphenoides, and the Os Ethmoides. The Os Frontis is at the front of the cranium; the Os Occipitis is at its hind part; the Ossa Parietalia, one on each side, form its superior lateral parts; the Ossa Temporum, also, one on each side, form its inferior la- teral parietes; the Os Sphenoides is in the middle of its bottom part; and the Os Ethmoides is at the fore part of the centre or body of the sphenoid bone. The cavity thus formed for the brain, has three diameters, which may be learned by sawing vertically through the middle line of one scull, and horizontally through the cavity of another. THE CRANIUM. 121 The first diameter is the longest, and extends from the lower part of the frontal bone to the protuberance on the middle of the interior surface of the os occipitis; it is commonly about six inches and a half long. The second diameter includes the space between the superior margins of the temporal bones, where they are most distant from each other, and passing over the middle of the great occipital foramen, is about five inches. The third di- ameter is taken from the centre of the large hole in the occipital bone to the centre of the suture between the parietal bones; it is about five inches, also. Rather more than one-third of the ca- vity of the cranium is placed behind the second diameter, and it diminishes somewhat abruptly; but in front of this diameter the cavity is finished more gradually. When the face is separated from the cranium, the exterior surface of the latter, excepting its base, represents tolerably ac- curately the form and proportions of its cavity; allowance being made for the large sinuses in the lower part of the frontal bone, and for the thinness of the upper parts of the temporal bones. The diameters mentioned, can only represent what most fre- quently happens, for daily observation proves remarkable de- partures from them. Sometimes the transverse diameter is in- creased at the expense of the longest, which gives to the head a flatness before and behind. On other occasions, the vertical di- ameter is increased, whereby the head receives a conical form. In many individuals the first diameter is increased, which makes the two sides of the cranium more parallel and flat than usual. The elongation of the transverse diameter is the most common, and that of the vertical the least so. The capaciousness of the cranium is much the same in adult individuals of the same sex; from which it may be inferred that the excess of one diameter is obtained generally at the expense of the other. The male cranium is more capacious and thick than the female. The female sex is less liable to variations in these proportionate diameters than the male. Stature has but little influence on the capaciousness of the cranium, as giants and dwarfs have it of the same size; hence, the former seem to have very small heads, while the latter appear to have very large ones, the eye being deceived by the relative magnitude of their bodies. The fact seems to be now well ascertained, that continued Vol. I.—16 122 SKELETON. pressure, or, rather, resistance in a fixed direction, made upon the cranium of a growing infant will change its natural form. Peculiar ideas of beauty have induced certain tribes of savages to adopt this barbarous and unnatural practice. The late Pro- fessor Wistar* showed to his class, in 1796, a Choctaw Indian having this peculiarity; and a tribe now existing near the sources of the Missouri, continues the practice of flattening both the oc- ciput and the os frontis. In the Wistar Museum we have ten headst of Peruvian In- dians, brought from the Pacific Ocean, nine of which bear the strongest evidence of having been flattened by pressure, on the os frontis and on the os occipitis. The possibility of effecting such a change in the form of the cranium has been strongly contested; and Bichat, who admits it, acknowledges that he was unable to produce like modifications in puppies, kittens, and India pigs. The singular change, however, which is wrought upon the feet of Chinese ladies, strongly corroborates the opinion of the head being also susceptible of artificial modifications in its form. J SECT. II.--OF THE INDIVIDUAL BONES OF THE CRANIUM. 1. Frontal Bone, (Os Frontis, Frontal.) The frontal bone forms the whole anterior, and a portion of the superior, lateral and inferior parietes of the cranium. It is symmetrica], and, occasionally, is completely divided into two bones by the continuation of the suture between the parietal bones. Its external face is convex, and the internal concave. On the former may be observed a line, or slightly raised ridge, running, on the middle of the bone from above downwards, which is ex- pressive of the original separation between its two halves. The front surface of the bone is terminated on either side, below, by the orbitary ridge, a sharp and arched elevation, forming the » System of Anat. 3d edit. vol. i. p. 73, 1824. -j- Presented by Dr. James Corneck, U. S. Navy, to Dr. Physick. $ In an examination of a female of this nation, Among Foy, the measurements were two inches and one-eighth from the heel to the end of the small toe; four and three-quarters of an inch from the heel to the end of the great toe; and the circumference of the ankle six and six-tenths of an inch. THE CRANIUM. 123 upper anterior boundary to the orbit of the eye. This ridge terminates outwardly by the external angular process, and in- wardly, by the internal angular process. Just above the internal half of the orbitary ridge the bone is raised, by the separation of its tables, into the superciliary or nasal protuberance or boss. Between the internal angular processes a broad serrated surface exists, by which the frontal bone is united to the nasal bones, and to the nasal processes of the superior maxillary bones. The centre of this surface is elevated into the nasal spine, which serves as an abutment to the nasal bones, and resists any force which might tend to drive them inwardly. On its exterior lateral surface, behind the external angular process, the frontal bone presents a concavity, bounded above by a well marked semicir- cular ridge, and intended for the lodgement of a part of the tem- poral muscle. On each side of the front part of the bone a prominence exists, most frequently better marked in infancy than in advanced life, and called by the French the frontal protuberance or boss. Proceeding backwards from the inferior part of the bone are the two orbitar processes, concave below and convex above. They are much thinner than other parts of the bone, and are separated by an oblong opening which receives the ethmoidal bone. A depression, large enough to receive the end of a finger, is at the exterior anterior part of the orbitar process, being pro- tected by the external angular process: this depression contains the lachrymal gland. Half an inch above the lower margin of the internal angular process, a much smaller depression exists, occasioned by the tendon of the superior oblique muscle where it plays upon its trochlea. In the orbitary ridge, just without the latter depression, is the super orbitary foramen or notch, for the passage of the frontal artery and nerve. The internal margins of the orbitar processes are broad and cellular, where they join the ethmoid bone; and at their fore part is seen a large opening on each side leading into the frontal sinus. These margins, in common with the ethmoid bone, form two foramina, one anterior, another posterior, and called internal orbitary; the first transmits the internal nasal branch of the ophthalmic nerve and the anterior ethmoidal artery and 124 SKELETON. vein, the latter transmits the posterior ethmoidal artery and vein. Externally and behind, the orbitar process presents a broad triangular serrated surface for articulating with the sphe- noid bone. The interior or cerebral face of the os frontis is strongly marked by depressions corresponding with the convolutions of the brain; on its middle exists a vertical ridge, becoming more elevated as it approaches the ethmoidal bone. This ridge is situated below, extends about one-half of the length of the bone, and terminates, above, in a superficial fossa, made by the longitu- dinal sinus of the dura mater; at its lower extremity is the fora- men coecum, common to it and the ethmoid bone, which is oc- cupied by a process from the great falx of the dura mater. It also affords passage to some very small veins, which go from the nostrils to the commencement of the longitudinal sinus.* The frontal sinuses consist in one or more large cells, placed beneath the nasal protuberances. There is a very great variety in their magnitude and extent; sometimes they proceed as far outwardly as the external angular process, and backwards for half an inch into the orbitar plates. In a few instances in the adult they do not exist, but the cases are very uncommon. The cells of the opposite sides have a complete partition. They com- municate with the cavity of the nose through the anterior eth- moidal cells. With the exception of the inferior part, where the processes and sinuses exist, the os frontis is of a very uniform thickness, and the diploic or cellular structure is found constantly between its external and internal surfaces. This bone is united to the parietal, ethmoidal, and sphenoidal, of the cranium; and to several bones of the face. '2. Parietal Bones, (Ossa Parietalia, Os Parietaux.) These bones, it has been stated, form the superior and lateral parts of the middle of the cranium. They are quadrilateral, .convex externally, and concave internally. Their external and internal tables are uniformly separated by a diploic structure, * Portal. Anat. Medicale. THE CKANIUM. 125 which, from being more abundant at the superior part of the bones, occasions there an increased thickness. The external surface of the parietal bone is raised about its middle into the parietal protuberance. Just below this protu- berance is an arched, rough, broad, but slightly elevated ridge, marking the origin of the temporal fascia and muscle, and con- tinuous with the ridge on the side of the frontal bone. The internal surface of the bone is marked by the convolutions of the brain; there are also a number of furrows upon it, having an arborescent arrangement, and produced by the ramifications of the middle artery of the dura mater. These furrows all pro- ceed from two large ones at the anterior and inferior part of the bone; not unfrequently at the latter point these furrows are con- verted into perfect tubes, by the deposition of bone all around the arteries. Of these furrows, the foremost may be traced from the greater wing of the sphenoidal bone, and the other from the squamous portion of the temporal. The internal face of the parietal bone also presents an imperfect fossa at its superior margin, which is completed by junction with its fellow, and ac- commodates the longitudinal sinus of the dura mater. Near this edge it is not uncommon to see one or more small irregular pits through the internal table, and looking somewhat ulcerated: these are formed by the glands of Pacchioni, in the dura mater. At the inferior posterior corner of the bone, there is a fossa, likewise, made by the lateral sinus. The superior, posterior, and anterior margins of the parietal bone are regularly serrated, and nearly straight. The inferior margin is concave, presenting a thin, bevelled, radiated surface before, for articulating with the squamous portion of the tem- poral bone: behind this concavity, the angle of the bone is trun- cated and serrated, for articulating with the angular portion of the os temporis. The anterior inferior angle is the most re- markable, from its being elongated so as to join the sphenoid bone in the temporal fossa. A foramen, called parietal, is found at the superior margin of this bone, nearer to its posterior than to the anterior edge; it transmits an artery between the integuments and dura mater, and also a vein from the integuments to the longitudinal sinus. 126 SKELETON. M. Portal says, that in some protracted headaches this vein swells considerably; and that he has seen much good in such cases, arise from the application of leeches to the part: he has also seen, in a child, its tumefaction the precursor of the pa- roxysms of epilepsy^. The parietal bone articulates with its fellow, with the frontal, the sphenoid, the temporal, and the occipital bones. 3. Occipital Bone, (Os Occipitis, Occipital.) This bone is quadrilateral, resembling a trapezium. It is convex externally, and concave internally; but both of these surfaces are much modified by ridges and processes. Its thick- ness is also very unequal; though, like the other bones, it has two tables, with an intermediate diploe. It is so placed as to form a considerable share of the posterior and inferior parietes of the cranium. The foramen magnum is placed in the lower section of this bone, and constitutes a very conspicuous feature in it. This hole is oval, the long diameter extending from before backwards. Its anterior inferior margin, on either side, is furnished with-a condyle, for articulating with the first vertebra of the neck. These condyles are long eminences tipped with cartilage, which converge forwards, so that lines drawn through their length would meet an inch in front of the foramen magnum; they re- cede behind: their internal margins are deeper than their exter- nal. The condition of their articular surfaces is therefore such, that they permit flexion and extension of the head, but not ro- tation. The anterior edge of the foramen is thicker than the posterior. This foramen transmits the spinal marrow, the ver- tebral arteries and veins, and the spinal accessory nerves. The external surface of the occiput presents, half way be- tween the foramen magnum and the upper angle of the bone, the occipital protuberance, from the lower part of which a small vertical ridge is extended in the middle line to the foramen. Into the ridge is inserted the ligamentum nuchae. From either side of the protuberance an arched ridge is extended to the la- THE CRANIUM. 127 teral angle of the bone; it is the superior semicircular ridge or line, from which arise the occipito frontalis and the trapezius muscles, and into it is inserted a part of the sterno cleido-mas- toideus. Below this about an inch is the inferior semicircular ridge, more protuberant, but not so distinctly marked in its whole course. Into the inner space, between the upper and lower ridges, is inserted the complexus muscle, and into the outer space between the same, the splenius muscle. The lower ridge is principally occupied by the origin of the superior ob- lique muscle of the neck. The inner space between this ridge and the great foramen gives origin to the rectus posticus minor, and the outer space to the rectus posticus major. Into a small elevation, leading from the outside of the condyle directly to the margin of the bone, is inserted the rectus capitis lateralis. In a depression behind each condyle is the posterior condy- loid foramen, which conducts a cervical vein to the lateral sinus. Passing through the base of the condyle, and having its orifice in front, is the anterior condyloid foramen for conducting the hypoglossal nerve to the tongue. That part of the bone before the condyles is the cuneiform or basilar process: the base of which is marked by depressions for the insertion of the recti muscles, which are situated on the front of the cervical vertebrae; and its fore part, which is trun- cated at the end, overhangs the pharynx, and is placed against the body of the sphenoid bone. The superior external part of the os occipitis is uniformly convex, being covered by the oc- cipito frontalis. The internal surface of the os occipitis is strongly impressed by ridges and depressions. On that portion of it behind the great foramen, is a rectangular cross, forming at its centre a large internal protuberance. The upper limb of the cross is marked by a fossa for the longitudinal sinus; the two horizon- tal limbs are also marked, each by its respective fossa, which receives the corresponding lateral sinus. The right fossa is fre- quently the largest. The inferior vertical limb of the cross has 128 SKELETON. attached to it the small falx of the dura mater, and is slightly depressed by a small sinus. The spaces between the limbs of the cross are much thinner than other parts of the bone, and present broad concavities, the two superior of which receive the posterior lobes of the cerebrum, and the two inferior, the lobes of the cerebellum. The superior face of the cuneiform process is excavated, lon- gitudinally, to receive the medulla oblongata. On each side of the foramen magnum, a short curved fossa is observed, which receives the lateral sinus just before its exit from the cranium. The two superior margins of the occipital bone are regularly serrated. The inferior margins have each, in their centre, a process termed the jugular eminence, in front of which is a rounded notch, forming a part of the jugular fossa, which trans- mits the internal jugular vein and the eighth pair of nerves. The edge of the bone above this eminence is serrated, but be- low it is rather smooth and rounded, being parallel with the temporal bone, and having an imperfect adhesion to the petrous part of it, before the jugular fossa. The occipital bone articulates above with the parietal, lateral- ly with the temporal; and in front with the sphenoid. 4. Temporal Bones, (Ossa Temporum, Temporaux.) These bones form portions of the inferior lateral parietes, and of the base of the cranium. Their figure is very irregular. Their circular anterior por- tion is called squamous: behind it is the mastoid, and between the others is the petrous. The squamous portion is thinner than the. other bones of the cranium that have been described, from the temporal muscle and its fascia covering it, so as to afford sufficient protection to the brain. Its exterior surface is smooth and slightly convex. The interior surface is formed into fossae by the convolutions of the brain. At the anterior inferior part of the latter surface, a THE CRANIUM. 129 groove is made by the middle artery of the dura mater imme- diately after it gets from the foramen spinale of the sphenoid bone on its way to the parietal, and a branch from this groove runs upwards and backwards. The greater part of the circum- ference of this portion is sloped to a sharp edge, but at the an- terior inferior part it is serrated and thicker. On the outside of the latter is the glenoid cavity, for articulating with the lower jaw, the length of it is transverse, with a slight inclination back- wards, so that a line drawn through it, would strike the fora- men magnum occipitis. The anterior margin of this cavity is formed by a tubercle, on which the condyle of the lower jaw rises when the mouth is widely opened. The outer margin of the glenoid cavity is formed by the root of the zygomatic pro- cess. The zygomatic process has a broad horizontal root, from which it extends outwardly, and then diminishing, runs forwards to join the malar bone. Posterior to the root of the zygomatic process, a small vertical groove may be seen occasionally, made by the posterior deep-seated temporal artery. The mastoid portion of the temporal bone, js thick and cel- lular. Its upper part forms an angle, which is received between the parietal and occipital bones: both margins of this angle are serrated. Below, is the mastoid process, a large conical pro- jection eight lines long, into which are inserted the sterno-mas- toid, and trachelo-mastoid muscles. At the inner side of its base is a fossa, affording origin to the digastric muscle. The inner face of the mastoid portion is marked by a deep large fossa for the lateral sinus of the brain. In the posterior part of the suture, uniting the mastoid portion and the occipital bone, or in the former bone near the suture, is the mastoid foramen, for conducting a vein from the integuments into the lateral sinus. The cells in the mastoid bone are large and numerous, and obtain the name of sinuses; they communicate with the tym- panum by one large orifice. On the outer side of these sinuses a common diploic structure is observable. The petrous portion of the temporal bone is a triangular Vol. I.—17 130 SKELETON. pyramid, arising by a broad base from the inner side of the mastoid and squamous portions. It is fixed obliquely forwards, between the sphenoid and occipital bones. Its anterior surface is marked by the convolutions of the brain. Near the centre of this surface, and having a little superficial furrow leading to it, is a small foramen called the hiatus Fallopii, through which passes the Vidian nerve. The posterior surface of the petrous portion presents a large foramen, the meatus auditorius internus, through which passes the seventh or the auditory and the facial nerve. Half an inch behind this orifice, is a very small one, overhung by a flat shelf of bone; this is said to be the aqueduct of the vestibule. Just above the meatus auditorius is a foramen more patulous than the aqueduct, for transmitting small blood vessels. In the base of the petrous portion, between the mastoid and zygomatic processes, is the meatus auditorius externus, a large opening conducting to the tympanum. It is oval, about half an inch deep, and varies much in its size in different subjects. Its margin is called the auditory process, the lower part of which is very rough, for attaching the cartilage of the external ear. The lower surface of the petrous bone is exceedingly irregu- lar. Immediately below the meatus externus, is a depression which seems like a part of the glenoid cavity, and is improper- ly considered as such by anatomists, inasmuch as it does not form a portion of the articular surface for the lower jaw, but simply allows room for its motions, the parts which it contains (consisting of vessels, and a portion of the parotid gland) being pressed back when the jaw opens. Between this cavity and the glenoid is the glenoidal fissure, separating the petrous from the squamous bone. In this fissure, leading to the tympanum, is a foramen which contains the processus gracilis of the mal- leus with its muscle, and the chorda tympani. The posterior margin of the depression alluded to in the petrous bone, is made by a long rough ridge, called processus vaginalis; just behind which, and partially surrounded by it, is the styloid process. The styloid process is round, tapering and an inch and a half long; but frequently absent in prepared skulls, from accidental THE CRANIUM. 131 fracture and from being in a cartilaginous state. From it arise the styloid muscles. Behind the root of the styloid process, is the stylo mastoid foramen, which transmits the portio dura or facial nerve to the face. Just within the styloid process and foramen is a deep de- pression, called jugular fossa, large enough to receive the tip of the little finger. The fossa, along with a corresponding one in the os occipitis, is occupied by the internal jugular vein and the eighth pair of nerves. Immediately before the lower end of this fossa is the foramen caroticum, being the lower orifice of a crooked canal, which terminates at the apex of the petrous bone, and transmits the carotid artery and the upper extremity of the sympathetic nerve. At the inner side of the carotid canal, a superficial serrated groove is perceived, which receives the adjoining edge of the occipital bone. Just in advance of the inner part of the jugular fossa is a small spine of bone, at the foot of which is a pit, containing the orifice of the supposed aqueduct of the cochlea. The spine separate's the eighth pair of nerves from the internal jugular vein. In the angle between the squamous and petrous bones, within the glenoid foramen, is the orifice of the Eustachian tube. The tube is divided longitudinally, by a bony partition. The up- per division contains the tensor tympani muscle. A small groove exists along the superior angle of the petrous bone, and another along the inferior angle, adjoining the basilar process of the occipital bone, and formed in part by it: they are made by the superior and inferior petrous sinuses. The temporal bone articulates with the occipital, the parietal, the sphenoid, and the malar. 5. Sphenoid Bone, (Os Sphenoides, Sphinoide.) The sphenoid is a symmetrical, but very irregular bone, placed transversely in the middle of the base of the cranium. It consists of a cuboidal body in the centre, of a very large process on either side of the body, and has, also, a number of angular margins and projections about it. In regard to the body of the sphenoid bone, from its upper 132 SKELETON. anterior part arise one on each side, the apophyses of Ingrassias, or the little wings. These wings have a broad horizontal base, and extending themselves outwardly, terminate in a sharp point. Their anterior edge is serrated for articulating with the os fron- tis: the posterior edge is smooth. Between the two wings, in front, is a prominence united to the ethmoid bone. The base of the wing is perforated by the foramen opticum, for trans- mitting the optic nerve with the ophthalmic artery. Below and behind this foramen, the little wing terminates in a point, called the anterior clinoid process. Between the foramina op- tica is a ridge of bone, sometimes called processus olivaris, and just above the ridge a groove, made by the optic nerves where they unite. Behind the ridge is a depression, the Sella Tur- cica, for containing the pituitary gland. This depression is bounded behind by a very elevated transverse ridge, called the posterior clinoid process. At either extremity of the base of the latter, a groove (sulcus carolicus) is made by the carotid ar- tery, which groove may be traced indistinctly under the ante- rior clinoid process, where it forms a notch, and sometimes a foramen. The posterior face of the body of the sphenoid bone, presents a flat surface for articulating with the cuneiform process of the occipital. Most frequently, in the adult, the bones are anchylosed at this junction. The inferior part of the body of the sphenoid presents a rising, in its middle, called the sphenoidal or azygous process, for articulation with the vomer, and with the nasal sep- tum of the ethmoid. On each side of this process, in front, is the orifice of the sphenoidal cell. These cells consist, most common- ly, of one on each side, and are separated by a bony partition. In the very young bone they are not formed. The body of the sphenoid undergoes so many changes between early infancv and adult life, by the conversion of its diploic structure into sinuses or cells, and is also so much modified in different individuals, that a general description of it will not answer, for all specimens. The two great wings arise from the sides of the body of the sphenoid, by a small irregular base. From their lower part pro- ject downwards, on either side, the two pterygoid processes called external and internal. These processes have a common base, are partially separated behind by a groove called pterygoid fossa THE CRANIUM. 133 and below by a notch. The internal is the longest, and is termi- nated by a hook, on the outer side of which is a trochlea made by the tendon of the circumflexus muscle. The external ptery- goid process is the broadest. By applying together the temporal and sphenoid bones, a groove, common to the two, leading to the Eustachian tube, will be seen. This groove is continued obliquely across the root of the internal pterygoid process, and indicates the course of the cartilaginous portion of the Eustachian tube. The internal pterygoid process sends out, from its base, a small shelf of bone, separated by a fissure from the under part of the body of the sphenoid. The posterior edge of the vomer rests against this projection. The fissure is filled up in advanced life. The great wings of the sphenoid bone present three faces. One is anterior, and called orbital, from its forming a part of the orbit; another is external, and called temporal; and the third is towards the brain, and forms a considerable part of the fossa for containing its middle lobe. The orbital face is square and slightly concave. The temporal face is an oblong concavity, at the lower part of which is a triangular process, giving an origin to the external pterygoid muscle. The cerebral face is concave and marked by the convolutions of the brain, as well as by a furrow made by the principal trunk of the great artery of the dura mater as it passes from the temporal bone to the temporal angle of the parietal. The inferior portion of the great wing is elongated backwards into a horizontal angle, called the spinous process, which is fixed between the petrous and squamous portions of the temporal bone. From the point of the spinous process pro- jects downwards the styloid process. The great wing presents a triangular serrated surface above, at its outer end, by which it articulates with the os frontis; just below this, in front, is a short serrated edge, by which it articulates with the malar bone; and, externally, is a semicircular serrated edge, by which it articulates with the squamous portion of the temporal bone. The tip of the large wing generally articulates also with the parietal bone. , Between the apophysis of Ingrassias and the greater wing is the foramen sphenoidale, called also foramen lacerum superius of the orbit. It is broad near the body of the bone, and becomes a 134 SKELETON. mere slit at the extremity of the little wing. Through it pass the third, fourth, the first branch of the fifth, and the sixth pair of nerves. Two lines below the base of this hole is the foramen rotundum, for transmitting the second branch of the fifth pair of nerves. Eight lines, or thereabouts, behind the foramen rotun- dum, is the foramen ovale, for transmitting the third branch of the fifth pair of nerves. Two lines behind the foramen ovale is the foramen spinale, for transmitting the middle artery of the dura mater. In the under part of the bone, and passing through the root of the pterygoid processes, is the foramen pterygoideum, for transmitting the pterygoid nerve; it being a recurrent branch of the second branch of the fifth pair of nerves. The sphenoid* bone articulates above and in front with the vomer, the frontal, ethmoidal, malar, and parietal bones: late- rally with the temporal, behind with the occipital, and by its pterygoid processes with the palate bones. 6. Ethmoid Bone, (Os Ethmoides, Ethmoide.) This bone is placed between the orbitar processes of the os frontis, and, as has been stated, fills the vacuity between them. It is cuboidal, extremely cellular, and light. The horizontal portion between the orbitar processes is the cribriform plate, called so from its numerous perforations. This is divided, longitudinally, above and below, by a vertical process; and from the under surface, on each side, is suspended a cel- lular portion. The vertical process on the superior face of the cribriform plate is-the crista galli, which extends sometimes from the back to the front of this plate, and is thickest in the middle. The com- mencement of the great falx arises from it, and occasionally it contains a cell or sinus opening into the nose. Between the front of the crista galli and the os frontis, is the foramen ccecum, al- ready described. On either side of the crista galli the cribriform plate is depressed into a gutter for holding the bulb of the olfac- * This bone is, by some anatomists, described in common with the os occipitis, as the os basilare, in consequence of their early junction into a single piece. THE CRANIUM. 135 tory nerve, and is perforated with many holes for transmitting its ramifications. The most anterior foramen on each side is oval, and transmits to the nose the internal nasal nerve, after it has got into the cranium through the anterior internal orbitar fora- men. The margins of the cribriform plate show many imperfect cells, which are completed by joining their congeners in the mar- gins of the orbitar processes of the os frontis. The vertical plate below the cribriform is called nasal lamella. It generally divides the nostrils equally, but is occasionally in- clined to one side. It joins below, to the vomer and the cartila- ginous septum of the nose; in front is in contact with the nasal spine of the frontal bone and with the nasal bones; and behind, with the azygos process of the sphenoid. Each cellular portion of the ethmoid forms, by its exterior, a part of the orbit of the eye, which surface is called os planum. The internal or nasal face forms part of the nostril. The fore part of this face is flat, but, posteriorly, in its middle, is a deep sulcus, called the superior meatus of the nose. The upper tur- binated bone, a small scroll, constitutes the upper margin of this meatus. The inferior internal margin of the cellular portion of the ethmoid, is formed by another scroll of bone, running its whole length. This is the middle turbinated bone. Moreover, from the inferior margin of the cellular portion, one or more la- minae, of an irregular form, project so as to diminish the opening into the upper maxillary sinus. The cells in the ethmoid bone are numerous and large, the posterior ones discharge, by one or more orifices, into the upper meatus. The anterior discharge into the middle meatus of the nose by several orifices, concealed by the middle turbinated bone. The most anterior of these cells is funnel-shaped, and joining the frontal sinus, conducts the discharge of the latter into the nose. In children of from three to eight years of age, there is at- tached to the posterior part of each cellular portion of the eth- moid, a triangular hollow pyramid, consisting of a single cell. 136 SKELETON. This pyramid arises, not only from the cellular portion, but also from the posterior margin of the cribriform plate, and of the na- sal lamella, by which it gains a large and secure base. The pro- cessus azygos of the sphenoid bone is received between the two pyramids. In the base of the pyramid, communicating with the nose, is a foramen, which is known in adult life as the orifice of the sphenoidal sinus. The pyramid, towards puberty, becomes a part of the sphenoidal bone, and then detaches itself, by a su- ture at its base, from the ethmoidal. As life advances it is greatly developed, no indication of its original condition remains, and it becomes fairly the sphenoidal cell; singularly differing in shape from what it was in the beginning.* Being put upon the investigation of this pyramid by the late Professor Wistar, with the view of ascertaining its different phases of development, it has occurred to me to see it in every stage, from that of a simple triangular lamina, arising from the poste- rior margin of the cribriform plate, to the perfect hollow pyra- midal state. All other anatomists describe it but imperfectly; it remained for that distinguished individual to elucidate its real history. Several of the articulations of the ethmoid have been men- tioned ; the remainder will be introduced with the bones of the face. SECT. III.--OF THE FACE. The face being situated at the inferior anterior part of the base of the cranium, is bounded above by this cavity, laterally by the zygomatic arches and fossae, and posteriorly by the space occupied by the pharynx. The best way of obtaining precise information concerning its form and composition, is from the head of an infant, of from five to ten years, in which the bones can be easily parted. In the adult, somewhat advanced in life, the bones cannot be separated so perfectly, from their being fused more or less together by the obliteration of the sutures. * Wistar's Anatomy, vol. i. p. 31, 3d edit. THE FACE. 137 The face is composed by fourteen bones, of which thirteen en- ter into the upper jaw. Twelve of the thirteen are in pairs: they are the ossa maxillaria superiora, ossa malarum, ossa nasi, ossa ungues, ossa turbinata inferiora, ossa palati. The thirteenth is the vomer. A single bone, with corresponding or symmetrical sides, constitutes the maxilla inferior. 1. Superior Maxillary Bones, (Ossa Maxillaria Superiora, Maxil- laires Superieurs.) These may be known by their superior size, and by their com- posing almost the whole front of the upper jaw. They are too peculiar in their figures to admit of comparison with any common object. The superior face of these bones is formed by a thin triangu- lar plate, the orbitar process, which is the floor of the orbit. In the posterior part of this plate is a groove, leading to a canal ter- minating in the front of the bone, at the foramen called infra or- bitar. This foramen is situated just below the middle of the lower margin of the orbit, and gives passage to theVinfra-orbitar nerve, and an artery. Externally, the orbitar plate is termi- nated by a rough surface, the malar process, which articulates with the malar bone. The nasal process arises, by a thick, strong root, from the front upper part of the bone at its inner side. Its front edge is thin, the posterior margin is thicker, and the upper edge is short, being serrated for articulating with the os frontis. A fissure exists be- tween the orbitar process and the nasal process, for accommo- dating the os unguis, and the lachrymal sac. A groove, leading to the nose, is formed on the posterior face of the nasal process, and marks the situation and extent of the lachrymal sac. On that side .of the root of the nasal process, next to the cavity, of the nose, a small transverse ridge is seen, to which is attached the anterior part of the inferior turbinated bone. The under surface of the os maxillare superius is marked by the alveolar processes for lodging the teeth. These processes are broader behind than before, corresponding in that respect with Vol. I.—18 138 SKELETON. the teeth. Within the circle of the alveoli is the palate process, arising from the internal face of the body of the bone. The pa- late process has a thick root, is thin in the middle, and, where it joins its fellow, has its margin turned upwards into a spine, whereby its articular surface is increased. It presents an oblong concave surface above, constituting the floor of the nostril; be- low, it, with its fellow, and the alveolar processes, form one con- cavity, having a surface somewhat rough, which is the roof of the mouth. The palate process does not extend the whole length of the superior maxillary bone, but stops half an inch short of it, posteriorly, and with a serrated margin for the palate bone. When the two maxillary bones are in contact, in the suture, just be- hind the front alveolar processes, is seen the foramen incisivum, which bifurcates, above, into each nostril. This foramen con- tains a branch of the spheno-palatine nerve, and a ganglion formed from it. In front, just below the infra orbitary foramen, the bone is depressed, which depression is filled up in the living state with fat and muscles. But, behind, the maxillary bone is elevated into a tuberosity, between which and the malar process is a broad groove, in which the temporal muscle plays. The inner face of the upper maxillary bone presents a view of the large cavity in the centre of it, called antrum Highmorianum. The orifice by which this cavity communicates with the nose is much diminished by the palate bone behind, the ethmoid above, and the inferior spongy bone below. When the antrum is cut open a canal is seen on its posterior part, which conducts the nerve of the molar teeth to their roots, and a similar canal is seen in front of the antrum, for the nerves of the front teeth. The nerves, in both instances, come from the infra orbitary. The nerves, till they begin to divide into filaments, are between the lining membrane and the antrum, but afterwards they make complete canals in the alveolar processes. The antrum frequently communicates with the frontal sinus, through the anterior eth- moidal cells, which circumstance is omitted by most anatomists. This bone is articulated with the frontal, nasal, unguiform, THE FACE. 139 malar, and ethmoid, above; to the palate bone behind; to its fellow, and to the vomer, at its middle; and to the inferior spongy bone by its nasal surface.' 2. Palate Bones, (Ossa Palati, Palatins.) The palate bones, two in number, are placed at the back part of the superior maxillary, between them and the pterygoid pro- cesses of the sphenoid. For descriptive purposes they may be divided into three por- f tions—the horizontal or palate plate, the vertical or nasal plate, and the orbitar or oblique plate, placed at the upper extremity of the latter. The palate plate is in the same line with the palate process of the superior maxillary bone, and supplies the deficiency caused by its abrupt termination. It is square. The inferior surface is flat, but rough for the attachment of the lining membrane of the mouth. The superior surface is concave, and forms about one- third of the bottom of the nose. The anterior margin is serrated where it articulates with the palate process of the maxillare superius. The posterior margin is thin and crescentic. The internal extremity of the crescent is elongated into a point, from which arises the azygos uvulae muscle. The internal margin of the palate plate is thick and serrated for articulating with its fellow, the upper edge of it being turned upwards to join the vomer. The exterior edge touches the internal side of the max* illare superius, and from it arises the nasal plate. The nasal plate forms the posterior external part of the nos- tril, and is much thinner than the palate plate. Its side next the nose is slighty concave, and is divided into two unequal sur- faces, of which the lower is the smallest, by a tranverse ridge, that receives the posterior extremity of the lower turbinated or spongy bone. The external face is in contact with the internal face of the maxillary bone, and presents a surface corresponding with it. The nasal plate of the palate bone diminishes the opening into the antrum Highmorianum by overlapping it be- 140 SKELETON. hind. Backwards it joins the pterygoid process of the sphenoid bone, and overlaps its anterior internal surface. At the inferior and posterior part of the nasal plate, where the crescentic edge of the palate plate joins it, the palate bone is extended into a triangular process, called the pterygoid. This process, on its posterior surface, presents three grooves, the in- ternal of which receives the internal pterygoid process of the sphenoid bone, and the external groove receives the external pterygoid process of the same bone. The middle fossa has its surface continuous with the pterygoid fossa of the sphenoid bone, and may be seen, in the articulated head, to contribute to this fossa. The anterior surface of the pterygoid process of the palate bone presents a small serrated tuberosity, which is received into a corresponding concavity on the posterior surface of the maxil- lary bone, and contributes to the firmer junction of the two. On the external surface of the nasal plate, between it and the base of the pterygoid process, a vertical groove is formed, which is converted into a complete canal by the maxillary bone. The lower orifice of this canal is near the posterior margin of the palate. It is called the posterior palatine foramen, and trans- mits the palatine nerve and artery to the soft palate. Immedi- ately behind this canal there is, not unfrequently, a smaller one, running through the base of the pterygoid process of the palate bone, and transmitting a filament of the same nerve to the palate. The upper extremity of the nasal plate is formed by two pro- cesses, one in front and the other behind, separated either by a round notch or by a foramen. The posterior of the two, called also pterygoid apophysis, is inclined over towards the cavity of the nose. It is thin, and fits upon the under surface of the body of the sphenoid bone, and upon the inner surface of the internal base of the pterygoid process of the same. Its upper edge touches the base of the vomer. The anterior process is the orbitar por- tion of the palate bone. The orbitar portion or plate is longer than the pterygoid apo- physis, and is hollow and very irregular. It may be seen in the posterior part of the orbit wedged in between the ethmoid and THE FACE. 141 maxillary bone. The portion of it which is there seen, is the orbital face, and is triangular. On the side of the ethmoid bone its cells are seen, which are completed by their contiguity to the ethmoid and sphenoid. The' cells, in young subjects, are not always to be met with. The posterior face of the orbitar por- tion is winding and looks towards the zygomatic fossa. The notch between the orbitar portion and the pterygoid apo- physis is converted into a foramen, by that part of the body of the sphenoid bone which is immediately below the opening of the sphenoid cell. Through this foramen, called spheno-palatine, pass the lateral nasal nerve, the spheno palatine artery and vein. This bone can scarcely be studied advantageously except in the separated head. A single application of it to the maxillary, will then show how it extends from the palate of the mouth to the orbit of the eye; and how it is the connecting bone between the maxillary bone and the pterygoid process of the sphenoid. The palate bone articulates with six others. With the upper maxillary, the sphenoid, the ethmoid, the inferior spongy, the vomer, and with its fellow. The places of junction have been pointed out in the description of the bone. 3. Nasal Bones, (Ossa Nasi, Os du Nez.) s The ossa nasi, two in number, fill up the vacancy between the nasal processes of the superior maxillary bones. They are oblong and of a dense compact structure, being so applied to each other as to form a strong arch called the bridge of the nose, which is farther sustained by the nasal spine and the continuous oblique serrated surface of the os frontis. The ossa nasi are thick and serrated at their upper margins; below, they are thin and irregular. The surfaces by which they unite with each other are broad, having their edges raised where they join the nasal lamella of the ethmoid bone. The edge by which they join the nasal process of the upper maxil- lary bone is concave; the upper part of this edge is overlapped by the nasal process, but the lower part of it overlaps the nasal process. 142 SKELETON. On the posterior face of the os nasi, is to be seen a small longitudinal groove, formed by the internal nasal branch of the ophthalmic nerve, which penetrates the foramen orbitale ante- rius and the cribriform plate of the ethmoid bone. The ossa nasi articulate with each other in front, with the nasal processes of the upper maxillary behind, with the septum narium where they are in contact with one another, and with the os frontis above. 4. Unguiform Bones, (Ossa Unguis, Os Lacrymaux.) The unguiform is a very small thin bone, placed at the inter- nal side of the orbit, between the nasal process of the upper maxillary and the os planum. Its orbitar surface is divided into a face which is in a line with that of the os planum, and into an oblong vertical concavity, continuous with the concavity on the posterior surface of the nasal process, for lodging the lachrymal sac. Its inferior anterior corner is elongated into the nose, so as to join with a process of the inferior turbinated bone, where- by the ductus ad nasum is rendered a complete bony canal. This bone lies on the orbitar side of the most anterior ethmoid^ cells, and completes them in that direction. An important variety in the structure of this part of the or- bit occasionally occurs, in which the whole fossa for lodging the lachrymal sac, is formed by the unusual breadth of the nasal process of the upper maxillary bone. In this case, the only part of the os unguis which exists, is that in the same line with the os planum. Several examples have come under my own notice. Duverney has also mentioned it. Sometimes it is en- tirely wanting, in which case the os planum joins the nasal pro- cess.* A variety still more uncommon is mentioned by Ver- heyen, where the lachrymal fossa is formed exclusively by the os unguis. This bone articulates very loosely with the adjoining bones, so that it is frequently lost from the skeleton. It joins the os frontis above, the upper maxilla before and below, the os pla- num behind, and the inferior spongy bone in the nose. • 6ertin, Traite D'Osteol. vol. ii. p. 143. Paris, 1754. THE FACE. 143 5. Cheek Bones, (Ossa Malarum, Jugalia, Os de la Pommette.) These bones, two in number, are also called zygomatic by many anatomists. They are situated at the external part of the orbit of the eye, and form the middle external part of the face. The cheek bone is quadrangular, and has irregular margins. It consists of two compact tables with but little intermediate diploic structure. There are three surfaces to it. That which contributes to the orbit is crescentic, and is called the internal orbitar process. The one in front is convex, and forms part of the face; and be- hind the latter is a third surface, which is concave, and forms a part of the zygomatic fossa. Of the four margins, two are su- perior, and two inferior. The anterior of the two first is con- cave, and rounded off, to form the external and one-half of the lower edge of the orbit. The posterior upper border above is thin and irregular, and to it is attached the temporal fascia: it terminates behind by a short serrated margin, for articulating with the zygomatic process of the temporal bone. The ante- rior inferior margin, is serrated its whole length, for articulating with the superior maxillary bone. The posterior inferior mar- gin gives origin to part of the masseter muscle. Some anato- mists admit, also, a fifth margin to this bone, which is towards the bottom of the orbit, and articulates above with the great wing of the sphenoid bone, and below with the superior maxil- lary. Between these two parts is a notch, forming the outer extremity of the spheno-maxillary slit. The angles of this bone are called processes. The upper one, which is continuous with the external angle of the os frontis, is the superior orbitar, or angular process. The orbitar margin terminates below, in the inferior orbitar, or angular process. That portion of the bone which joins with the zygoma of the tem- poral, is the zygomatic process; and the fourth angle is the max- illary process. The os malae articulates with four bones; to wit, with the maxillary, frontal, sphenoidal, and temporal. 144 SKELETON. There are a few small foramina in this bone, which transmit nerves and blood vessels. 6. Inferior Spongy Bones, (Ossa Spongiosa aut Turbinata Inferio- ra, Cornets Inferieurs.) This pair of bones is situated at the inferior lateral parts of the nose, just below the opening into the antrum Highmorianum. They are very thin and porous, and their substance is extremely light and spongy. The internal face of the spongy bone is towards the septum of the nose, and presents an oblong rough convexity. The ex- ternal face has a corresponding concavity towards the maxillary bone. The superior margin presents, in front, an upright pro- cess, which joins with the anterior inferior angle of the ungui- form bone, to form the nasal duct. Just behind this, the margin of the bone is turned over towards the antrum, forming a broad hook, which rests upon the lower margin of the orifice of the antrum, and diminishes its size. From the superior margin, also, one or two processes not unfrequently arise, whereby this bone joins the ethmoid. The inferior margin is somewhat thicker than the superior. The anterior extremity of this bone rests upon the ridge across the root of the nasal process of the upper maxillary. The posterior extremity rests, in like manner, upon the ridge across the nasal plate of the palate bone.* The Ploughshare, (Vomer.) This single bone is placed between the nostrils, and forms a considerable part of their septum. It is frequently more in- clined to one side than to the other. It is formed of two laminae, between which there is a very thin diploic structure. The sides of the vomer are smooth and parallel: It has four margins. The superior is the broadest, and has a furrow in it for receiving the azygous process of the sphenoid bone. The anterior margin is directed obliquely downwards and forwards, * In some rare cases this bone adheres to the ethmoid, so as to become a part of it. THE FACE. 145 of which the front half joins the cartilaginous septum of the nose, and the other half receives, in a narrow groove, the nasal plate of the ethmoid. The posterior margin of the vomer is smooth and rounded, making the partition of the nostrils behind. The inferior mar- gin articulates with the nasal spine of the superior maxillary and palate bones. Lower Jaw, (Os Maxillare Inferius, Maxillaire Inferieur.) This bone forms the lower boundary of the face, and is the only one in the cranium capable of motion. In early life, its two halves are separable, being joined at the middle line only by cartilage; but, in the course of two or three years after birth, they are fused together, and the original cartilage disappears. It consists of a body and two extremities or branches. The inferior part of the body presents a thick and rounded edge; it is the base. The upper part of the body is formed by the alveolar cavities for receiving the teeth. The line of union between the two halves, called the symphysis, is marked in front by an elevated ridge, terminated below by a triangular rising, the anterior mental tubercle. In many subjects this tubercle is bounded on each side by a rounded prominence of bone, which gives to the fore part of the jaw an unusual squareness in the living subject. Just above the latter prominence, there is, on each side, a transverse depression, from which arises the levator muscle of the lower lip. On a line with this depression, and re- moved a little distance from its external extremity, under the in- terstice between the second small and the first large molar tooth, is the anterior mental or maxillary foramen, the termination of a large canal in either side of the bone which conducts the in- ferior maxillary blood vessels and nerves to the teeth. The fo- ramen is directed obliquely upwards and backwards, and trans- mits the remains of the blood vessels and nerves to the face. The chin is that part of the bone between the anterior mental foramina. As the alveolar processes do not exist in early life, and in very advanced age when the teeth are lost, the anterior mental foramen in such cases is very near the superior margin of the bone. At it an obtuse ridge of bone commences, which Vol. I.—19 146 SKELETON. ends in the root or anterior edge of the coronoid process. The alveolar processes of the three last molar teeth are placed with- in this ridge, and project over the internal face of the bone. The internal or posterior face of the lower jaw is also marked at the symphysis by a ridge passing from the superior to the in- ferior margin. At the lower part of this ridge is a cleft process, the posterior mental tubercle. Below this tubercle, on either side, is a shallow fossa, for receiving the digastric muscle. Be- tween the lower margin of the bone and the protuberance occa- sioned by the alveolar processes of the larger molar teeth, is an oblong large fossa, made by the pressure of the sub-maxillary gland. The alveolar processes form a semicircle, the extremities of which are carried backwards with a slight divergence. The parietes of these processes are thin, and present cutting edges. They of course, correspond, in number and shape, with the roots of the teeth which they have to accommodate. The anterior ones are longer than the posterior. As a general rule, the alve- olar processes may be said to come and depart with the teeth; but, when a single tooth is extracted, the alveolar cavity not unfrequently is filled up with osseous matter, the edge of it alone being removed. This occurs more frequently in the lower than in the upper jaw. The base of the lower jaw does not present many marks worthy of attention. It should be observed, that its anterior part is thicker than the posterior. Sometimes, just before the angle of the bone, we see a concavity of this edge; but general- ly it is straight, or nearly so. The extremities or rami of the lower jaw arc quadrilateral, and rise up much above the level of the body. Their superior margin presents a thin concave edge, bounded in front by the coronoid, and behind by the condyloid process. The coronoid process is triangular; its base is thick, but its apex is a thin rounded point. The condyloid process is a transverse cylindrical ridge, directed inwards, with a slight inclination backwards, its middle being somewhat more elevated than the extremities. It springs from the ramus by a narrow neck. There is a concavity THE FACE. 147 at the inner fore part of its neck for the insertion of the ptery- goideus externus, and a convexity behind. The external face of the ramus is flat, but marked by the in- sertion of the masseter muscle. The internal face, at its lower part is flat and rough, for the insertion of the pterygoideus in- ternus. At the upper part of this roughness is the posterior mental or maxillary foramen, through which the maxillary ves- sels and nerve enter. It is partially concealed by a spine of bone, into which a ligament from the os temporis is inserted. Leading from this foramen is a small superficial groove, made by a filament of the inferior maxillary nerve. The angle of the inferior maxillary bone, formed by the meeting of the base and the posterior margin of the ramus, pre- sents diversities well worth attention, at different epochs of life, and in different individuals. In very early life, and in very advanced, when the alveoli are absorbed, it is remarkably ob- tuse. In most middle-aged individuals it is nearly rectangular. Besides which, its corner is sometimes bent outwards and some- times inwards, increasing or diminishing thereby the breadth of the face at its lower part. The substance of this bone, externally, is hard and compact. Internally there is a cellular structure, through the centre of which runs the canal for the nerves and blood vessels. From this canal smaller ones are detached, containing the vascular and nervous filaments which go to the roots of the teeth. The max- illa inferior articulates with the temporal bones, by means of their glenoid cavities. Remarks.—The maxilla inferior has a greater influence on the form of the face than any other bone entering into its composi- tion. Sometimes it is much smaller in proportion in certain in- dividuals than in others. Sometimes its sides, being widely se- parated, give a great shortening to the chin, and breadth to the lower hind part of the face. In many instances, the alveolar processes, in front, incline obliquely over the outer circumfe- rence of the bone, and thereby give to the chin the appearance of receding considerably. In others, the alveoli incline over the inner circumference, which causes the chin to project un- usually. 148 SKELETON. CHAPTER III. GENERAL CONSIDERATIONS ON THE HEAD. Having described the individual bones of the head, it will now be proper to consider it as a whole. SECT. I.--OF THE SUTURES. Except in advanced age, the bones of the cranium and of the face are very distinctly marked off and united by sutures. The latter are formed by the proximate edges of the bones, presenting a multitude of sharp serrated points, and of deep narrow pits, by which they are brought into accurate and firm contaet. Here and there, in the sutures which unite the flat bones of the cranium, we find not only sharp points, but com- plete dove-tail processes of the one bone received into corre- sponding cavities of the other. The denticulation of the sutures is much more common, and much better marked, on the exter- nal than on the internal surface of the cranium. On the latter, the union of the bones is, in several instances, by a joint nearly straight; in which case, the denticulation is almost exclusively confined to the external table and to the diploic structure. The Coronal Suture, (Sutura Coronalis,) so named from its corresponding in situation with the garlands worn by the an- cients, begins at the sphenoid bone, about an inch and a quarter behind the external angular process of the os frontis. It in- clines so much backwards in its ascent, that when we stand erect, with the head in its easiest position, a vertical line, dropped from its point of union with the sagittal suture, would pass through the centre of the base of the cranium, and would cut another line drawn from one meatus auditorius externus to the other. It unites the frontal bone to the two parietal. The Sagittal Suture (Sutura Sagittalis) unites the upper margins of the two parietal bones, and is immediately over the THE SUTURES. 149 division between the hemispheres of the cerebrum. It has been stated in the account of the os frontis, that sometimes it is continued through the middle of this bone down to the root of the nose. The Lambdoidal Suture (Sutura Lambdiformis) is named from its resemblance to the Greek letter lambda, and consists of two long legs united angularly. It begins at the posterior termination of the sagittal suture, and continues down to the base of the cranium, as far as the jugular eminences of the oc- cipital bone. Its upper half unites the occipital to the parietal bones, and the lower half the occipital to the temporal bones. The latter half is sometimes called the Additamentum Sutura? Lambdoides. The Squamous Suture (Sutura Squamosa) is placed on the side of the head, and unites the parietal to the temporal bone. The convex semicircular edge of the latter overlaps the con- cave edge of the former. The squamous suture is converted into the common serrated one, where the upper edge of the an- gle of the temporal bone joins the parietal. This portion is called the Additamentum Suturae Squamosal. In the upper part of the lambdoidal suture particularly, we find in many skulls one or more small bones, connected to the parietal and occipital bones by serrated margins. They are called the ossa Wormiana or Triquetra. They vary very much in their magnitude, being in different subjects from a line to one inch, or an inch and a half in diameter. I have seen them of the latter size, and occupying entirely the place of the superior angle of the os occipitis. Most commonly, but not always, when one of these bones exists on one side of the body, a cor- responding one exists on the other. A congeries of these bones, united successively, is sometimes found in the lambdoidal su- ture; in such cases they are, for the most part, small. Com- monly these bones consist, like the other bones of the cranium, of two tables and an intermediate diploe, and form an integral portion of the thickness of the cranium; sometimes, however, they compose only the external table. M. Bertin says, that 150 SKELETON. he has seen them, also, composing only the internal table of the cranium. All the sutures mentioned besides the lambdoid, may exhi- bit, at any of their points, the ossa Triquetra or Wormiana. I have seen them in the coronal, the sagittal, and the squamous, but in such cases they are small. The lambdoid unquestionably has them most freq'uently. M. Bertin has seen a large square bone at the fore part of the sagittal suture, occupying the place, and presenting the form, of what was once the anterior fonta- nel: he has also seen triquetral bones in the articulations of the bones of the face.* The sutures described belong exclusively to the cranium, but there are others common to it and to the face. The sphenoidal suture surrounds the bone from which its name comes; the eth- moidal suture surrounds the ethmoidal bone; the zygomatic su- ture unites the temporal and malar bones; the transverse suture runs across the root of the nose, and also unites the malar bones to the os frontis. The other articular surfaces of the face de- rive their names from the bones they unite, and do not merit a particular attention at this time, as enough has been said in the description of the bones themselves. The base of the cranium is remarkably different, in the man- ner of its articulations, from the upper part. The surface, in the first place, is very rugged, and much diversified by its con- nexion with muscles and bones: besides which, there is a con- siderable number of large foramina and fissures in it. To guard against the weakness arising from the latter arrangement, nature has given a very increased thickness to the base, particularly where much pressure from the weight of the head exists, and has applied unusually broad surfaces of bone to each other to secure them from displacement by concussion, and different kinds of violence. These arrangements are particularly manifest at the junction of the cuneiform process of the occipital bone with the body of the sphenoid, which, in the middle-aged, is anchy- losed;—at the lower part of the lambdoidal suture;—and at the margins of the petrous portions of the temporal bones where they touch the contiguous bones. Whence it results that the * Bertin, loc. cit. THE SUTURES. 151 several fastenings of the base of the cranium, and of the upper maxilla, are so complete and strong, that they are most general- ly perfectly exempt from dislocation; and when the violence of- fered to them is sufficiently great, the bones, in place thereof, are fractured. The use of the sutures, in the cranium and upper maxilla, is somewhat problematical; for as none of the bones move, the head might have been equally well arranged by being made of a single piece. In proof of which it is only necessary to re- collect, that in the very aged there is frequently not a bone of the cranium and upper maxilla to be found in an insulated state: they are all fused into the adjoining bones, by the oblite- ration of their sutures. The old notion that sutures existed for the purpose of arresting the course of fractures, and for opening in some diseased conditions of the brain, has been very justly exploded. We know that a fracture will traverse a su- ture readily, and that the opening of the sutures from hydro- cephalus is an occurrence only of very early infancy, where the sutures have not arrived at the serrated and dove-tail arrange- ment, by which they are subsequently secured. It is much more probable that the true reason for the existence of sutures, is found among the laws peculiar to the growing state; and which most commonly are suspended after the several developments have been accomplished. Thus, the head, in consequence of being separated by sutures into many pieces, is more readily wrought from its form and size in the embryo state, to the form and size required by adult life. This necessity of subdivision into many pieces, does not depend so much on the size, as on the shape of the head. For we find the largest animal, as the elephant, having no more sutures than the smallest, as the mouse. This opinion is also sustained by what we see in other bones. Bones of a very simple shape, as those of the tarsus and carpus, consist from the very beginning of but one piece. But where the shape of a bone is complicated, we find it, while growing, submitted to the same law as the head at large, and consisting of many pieces. In such cases these pieces are united by a species of suture corresponding precisely with the form of suture observed between some of the bones of the cranium; as, for 152 SKELETON. example, between the occipital and the sphenoid. Thus, the os femoris, till adult age, consists of five pieces; its two articular extremities, its body, its trochanter major, and its trochanter minor. The cranium itself, before birth, and for some time af- ter, has several of its individual bones consisting each of two or more pieces, which favours still more the idea. Some persons think that the sutures of the adult are only re- mains of an arrangement intended exclusively for the benefit of the parturient state, by maintaining a plasticity of the head of the foetus, which admits of its diameters accommodating them- selves to the diameters of the pelvis of the mother. This theory is rather too exclusive, though it may be admitted that the sutures in a foetal head have that use, and are in some cases of parturition a most fortunate coincidence, by which the lives of both parties are saved. But it should be observed that in a great number of cases, the head of the foetus never changes its form in passing through the pelvis, because the passage is quite large enough without it; and, again, if the sutures were intended expressly for the parturient state, we ought not to find them in birds, and in such animals as are hatched, because the necessity for them there does not exist.* Upon the whole we may safely conclude, that the sutures of the cranium and face are simply a provision for the growing state, and that, like all other provisions for this state, it also ceases at its appropriate period, and sometimes leaves not a ves- tige of its existence. Occasionally, indeed, we find the latter to have occurred in one or more sutures, even before the age of puberty, as I have repeatedly witnessed of the sagittal, the squamous, and the lambdoidal sutures. The manner in which the sutures are formed is sufficiently interesting: they are generally said to be made by the radii of ossification, from the opposite bones meeting and passing each other, so as to form a serrated edge. This explanation may ac- count partially for the shape of the edge of the sutures, but not for their invariable position; inasmuch as we always find the * A gentleman whose anatomical writings have some vogue in this country, has cut the Gordian knot, by telling us that they are " accidental merely, and of little use.'.'"—Anat. of the Human Body, by John Bell, Surgeon, Edinburgh. THE SUTURES. 153 sutures in the same relative situation, and having the same course. If they depended exclusively on so mechanical a pro- cess, as the rays of one bone shooting across the rays of another by their own force, we ought to find occasionally, the sagittal suture more on one side of the head than on the other, and not straight, because in some instances ossification is a more rapid process on one side than on the other. Moreover, in all cases where bones arise from different points of ossification, and meet,. the serrated edge should be formed; and particularly in the flat bones. Observation, however, proves that the os occipitis, which is formed originally from four points of ossification, and therefore has as many bones composing it in early life, does not present these bones afterwards united by the serrated edge. The acromion process of the scapula, though originally distinct from the spine, never unites to it by suture, but always by fusion. The mode of junction in the three bones of the sternum is al- ways by fusion. In short, the observation holds good in nu- merous other instances. Bertin and Bichat, reject fully the mechanical doctrine con- cerning the sutures, and present one founded upon reason and observation, and susceptible of confirmation by any accurate ob- server. The dura mater and the pericranium, before ossification commences, form one membrane consisting of two laminae. Partitions pass from one of these laminae to the other, which mark off the shape, or constitute the mould of the bones long before they are perfected. The peculiar shape of the bony junction, or, in other words, of the sutures or edges of the bones in adult life, depends, therefore, exclusively upon the original shape of the partitions. When the latter are serrated, the points of ossification will fill up these serrae; but when they are oblique, the squamous suture will be subsequently formed. This theory also accounts for modes of junction intermediate to the squamous and serrated suture; for the formation of the ossa Triquetra or Wormiana; for their existence, form, size, and number, in some skulls, and their total absence in others. The inference will also be obvious, that in all ossifications from dif- ferent nuclei, a suture will not be formed, where the membra- nous partitions do not exist; but that the bones will unite after the manner of such as are fractured. We shall also understand. Vol. I.—20 V 154 SKELETON. that when these partitions are weak and imperfect, either from their congenital condition, or from advanced age, as happens in all sutures, but with some differences of time, the bones of the opposite sides are fused together completely. The partitions which determine the places of the sutures, may be demonstrated in a young adult skull by removing with mu- riatic acid the calcarious portion of the bones, so as to leave only the animal part. On opening the suture after this process, it will be seen, that the pericranium sends in its partition, which is met by the partition coming from the dura mater. Or, if either of these membranes be peeled off, its contribution of par- tition will appear very plainly projecting from its surface, in the form of a ridge- Owing to congenital hydrocephalus, the sutures of the vault of the cranium have been known to remain open for years after birth, from the continued augmentation of the volume of the brain. In such cases, additional bones are sometimes formed, manifesting a strong attempt, on the part of nature, to cover the brain with bone. I obtained, some years ago, a specimen of this kind belonging to a foetus of nine months, whose head was as large as it is commonly in adult life, and in whom there were two ossa parietalia on one side. Morgagni,* whose authority is proverbial in morbid anatomy, states, that a learned colleague and intimate friend of his, Bernardin Rammazzani, aged seven- ty, had the sutures open at that period of life. He does not say at what time this condition of them appeared. I think it more probable that they had never been closed, though Morgagni leaves the reader to infer, that it was a circumstance which had arisen from a violent hemicrania, with which the patient had been seized when he was advanced in life. Diemerbroek found, in a woman of forty, the anterior fontanel not ossified. Bauhius' wife, aged twenty-six, had the sutures not yet closed. Indeed, there is no deficiency of well authenticated similar instances, more of which it will be unnecessary to adduce. It may be ob- served here, that when from congenital hydrocephalus, attended with much extension of the brain, the bones of the cranium are compelled to grow beyond their usual diameters, they are un- * Causes and Seats of Disease, Letter 3d, Art. 8th. STRUCTURE OF THE CRANIUM. 155 commonly thin, and the diploic structure is very imperfectly developed; which will account for their separation at any period of life, from the fastening being so slight. SECT. II.--OF THE DIPLOIC STRUCTURE OF THE CRANIUM. The bones of the cranium, in the adult, consist of an external and of an internal table; united by a bony reticulated or cellu- lar substance, which does not manifest itself very distinctly till two, three, or even more years are passed, by the infant. The internal table of the skull is thinner and more brittle than the external, and has obtained, from that cause, the name of vitreous table. The cells of the diploic structure are not to be confounded with the large sinuses that exist in the frontal, the temporal, and the sphenoidal bones. They are formed under different circum- stances, and do not communicate with them. The sinuses are lined by a mucous membrane, whereas the lining membrane of the cells of the diploe corresponds with the internal periosteum of other bones. I have a preparation now before me, in which the diploic structure of the os frontis exists between its sinuses and the external table of the bone: in the same head, a similar circumstance existed in regard to the temporal bone; from which we infer that the diploic structure, in these places, is caused to recede, and even to be partially obliterated, when the develop- ment of the sinus commences, which is not until some time af- ter the evolution of the diploic structure. The sphenoidal bone, when fully evolved in its body, is a remarkable instance of the recession of diploic structure for the purpose of forming a sinus. In the diploe of the dried bones, several arborescent channels* may be seen, by the removal of the external table. They were discovered about the year 1805, by M. Fleury, while he was Prosecteur at the School of Medicine in Paris: and engaged, at the instigation of the venerable Chaussier, in some inquiries re- lative to the structure of the cranium. The account given by the latter is, that these channels are occupied in the recent sub- jects, by veins, which, like all others, are intended to return the * Chaussier, Exposition de la Structure de 1'Encephale. Paris, 1807. 156 SKELETON. blood to the heart. These veins are furnished with small valves, have extremely thin and delicate parietes, and commence by capillary ramifications, coming from the different points of the vascular membrane, which lines the cells of the diploe. Their roots are at first extremely fine and numerous, form by their frequent anastomoses a kind of net-work, and produce by their successive junction, ramuscules, branches, and large trunks, which, becoming still more voluminous, are directed towards the base of the cranium. Some variations exist in regard to the number, size, and disposition of these trunks, but generally one or two of them are found on either side of the frontal bone, two in the parietal bone, and one on either side of the occipital bone. Anastomoses exist between these several trunks, by which the veins in the parietal bone are joined to those in the frontal and in the occipital. Branches from the right side of the head also anastomose, with some from the leftside. Besides the branches already mentioned, one or two smaller than the others are di- rected towards the top of the head, and terminate in the longi- tudinal sinus. The descending veins of the diploe communicate in their pas- sage with the contiguous superficial veins, and empty into them the blood which they receive from the several points of the di- ploe'. These communications are produced through small fora- mina, which penetrate from the surface of the bone to the diploe. The trunks of such diploic veins a» are continued to the base of the cranium, open, partly into the sinuses of the dura mater, and partly into the venous plexus at the base of the pterygoid apo- physes of the sphenoid bone, and form there the venous commu- nications through the foramina of the base of the cranium, called the emissaries of Santorini. Moreover, there are communica- tions sent from the diploic veins, through the porosities of the in- ternal table of the skull, to the. veins of the dura mater. This fact is rendered very evident by tearing off the skull-cap, when the surface of the dura mater will be studded with dots of blood, and the internal face of the bone also, particularly in apoplectic subjects. It appears, indeed, that the arteries of the cranium are principally distributed on its external su rface, and the veins on its internal surface and diploe. SURFACE OF THE CRANIUM. 157 In the infant the diploic veins are small, straight, and have but few branches: in the adult, they correspond with the descrip- tion just given, and, in old age, they are still more considerable, forming nodes and seeming varicose. In children, when the bones are diseased, they partake of the latter character. In order to see them fully, the external table of the skull must be removed, both from its vault and base, with a chisel and mallet. This ope- ration will be much facilitated by soaking the head previously in water for two days. SECT. III.--THE INTERNAL SURFACE OF THE CRANIUM. The points for study in viewing the cranium as a whole, are generally the same as have been presented in the detail of each bone. It is, nevertheless, useful to regard the structure in its connected state, as new views are thus presented of the rela- tive situation of parts, and of the formation of the several fossae and cavities. The cavity for containing the brain is regularly concave above, and is there called the arch or vault; but below, it is divided into several fossae, and is called the base. The whole cavity is lined by the dura mater, and, in the adult, presents round superficial depressions made by the convolutions of the brain. These depressions are seldom deep enough to pre- vent the internal periphery of the vault and sides of the crani- um, from being nearly parallel with their external surface. On the Vault, or arch, are to be seen, on the middle line, the frontal spine, extending from the ethmoid bone half way or more up the os frontis: also, the gutter for the longitudinal sinus lead- ing from this spine along the sagittal suture, and terminating at the internal occipital protuberance. On either side of this gut- ter are the arborescent channels, made by the great middle ar- tery of the dura mater. In this section, we also see the internal face of the os frontis, excepting its orbitar processes; the parie- tal bones; and the superior fossae in the occipital bone, for the posterior lobes of the cerebrum. The Base of the cranium internally presents a very unequal 158 SKELETON. surface, abounding in deep depressions, processes, and foramina. On its middle line, extending from before backwards, the follow- ing objects should be remarked. The foramen coecum at the front of the crista galli; and, at either side of the latter, the eth- moidal gutier, perforated with holes. These gutters are bound- ed, laterally, by the internal margin of the orbitar processes of the os frontis, and behind by the sphenoid bone. At the fore part of the gutter is the oblong foramen for transmitting to the nose the internal nasal nerve, and about half an inch behind this foramen, in the suture, with the os frontis, is the cerebral orifice of the foramen, called the anterior internal orbitar, which leads the same nerve from the orbit. Immediately behind the ethmoi- dal fossae the sphenoid bone presents a plane surface, upon which are placed the olfactory nerves and the contiguous part of the brain. Behind this plane is the fossae, running from one optic fo- ramen to the other, for lodging the optic nerves. Behind this, again, is the sella turcica or pituitary fossa, bounded at its two anterior angles by the anterior clinoid processes, and behind by the posterior clinoid process. Posterior to the latter is a plane square surface of the sphenoid bone, continuous with the internal surface of the cuneiform process of the os occipitis. On the latter is the depression called basilar gutter, for receiving the medulla oblongata, and which is bounded below by the great occipital fo- ramen. From this foramen to the internal occipital protuberance, proceeds the inferior limb of the occipital cross. On each side of the ethmoidal bone is a convex surface; called, however, the anterior fossae of the base of the cranium, and formed by the orbitar processes of the os frontis and the little wings of the sphenoid bone, for lodging the anterior lobes of the brain. This surface is terminated behind by the rounded edge of the little wings, which is received into the fissure between the anterior and middle lobes of the brain. Just anterior to this edge is the fronto-sphenoidal suture. On each side of the sella turcica are the middle fossae of the base of the cranium. They are very wide externally, where they are bounded by the squamous portions of the temporal bones, but narrow internally, where they are bounded by the pituitary SURFACE OF THE CRANIUM. 15'J fossa. The little wings of the sphenoidal bone terminate them in front, and form there a crescentic edge hanging over their cavity. Their posterior margin is the superior ridge of the petrous bone. This bone is placed very obliquely, inwards and forwards, and its point almost reaches the posterior clinoid process. At the ante- rior part of the fossa is the sphenoidal fissure, or the foramen magnum of the sphenoidal bone. Just above the base of this fis- sure is the foramen opticum, partially concealed by the anterior clinoid process. Just below the base of the fissure is the foramen rotundum. At the point of the petrous bone, by the side of the posterior clinoid process, is the internal orifice of the carotid ca- nal. On a line with the latter, exteriorly, is the foramen ovale. Two lines behind the latter is the foramen spinale. The groove formed by the middle artery of the dura mater, may be traced from the foramen spinale along the anterior margin of the squa- mous bone. Near the upper part of this bone the groove bifur- cates ; the larger channel runs upwards into a groove on the tip of the great sphenoidal wing, into the principal groove of the pa- ■ rietal bone, which commences at the temporal angle of the lat- ter. The smaller groove runs horizontally backwards, and just above the base of the petrous bone is continued also into the pa- rietal bone. On the front of the petrous portion may be seen the hiatus Fallopii. The sphenoidal suture runs through this fossa, in the examination of which, the reception of the spinous process of the sphenoid bone, between the squamous and petrous portions of the temporal, will be readily understood. On each side of the foramen magnum occipitis are the two pos- terior fossae of the base of the cranium, formed by the posterior faces of the petrous bones, the angles of the mastoid portions of the temporal bones, and by that surface of the occipital bone be- low its lateral gutters. These two fossae are very partially se- parated by the inferior limb of the occipital cross. The lambdoi- dal suture traverses these fossae. At the junction between the petrous bone and the basilar process of the occipital, in the course of the suture, is a groove for the inferior petrous sinus. The groove conducts to the posterior foramen lacerum, which has a small part separated from it by the little spine of the petrous bone, which, with the assistance of the dura mater, forms a distinct 160 SKELETON. foramen for the eighth pair of nerves. The posterior foramen lacerum being common to the temporal and occipital bones, is oc- casionally much larger on the right than on the left side: in which case, the groove that leads from it along the angle of the temporal bone, the inferior corner of the parietal and the hori- zontal limb of the occipital cross, is also larger. Above the fo- ramen lacerum are the meatus auditorius internus and the inter- nal orifice of the aqueduct of the vestibule. Between the foramen lacerum and foramen magnum occipitis is the anterior condyloid foramen. The two posterior fossae of the base of the cranium contain the cerebellum. SECT. IV.--OF THE EXTERNAL SURFACE OF THE HEAD. Anatomists, of modern times, consider the external surface of the head as forming or representing three ovals and two triangles, each of which constitutes a region. The first oval is the whole superior convex part of the cranium; or, in other words, the ex- ternal surface of its vault. The second oval is formed by the in- ferior surface of the cranium and of the face. The third oval is formed by the lower front part of the os frontis, and by the face. Each side of the head forms one of the triangular regions. The superior region is so simple, and its parts have been so closely sketched, that it is unnecessary to repeat the description. The inferior region or oval, extends from the chin to the oc- cipital protuberance, and is bounded in its transverse diameter by the superior semicircular ridges of the os occipitis, by the mastoid processes, and by the rami and base of the lower jaw. This region is subdivided into palatine, guttural, and occipital sections or regions. The Palatine region or section, is formed by the superior max- illary and palate bones, above, and by the inferior maxillary bone, laterally and below. It is a deep fossa, the circumference of which is represented by the letter U, the open part being be- hind. The whole upper surface of the palatine region, presents a number of small rough elevations and fossae, for the attach- ment of the lining membrane of the mouth. This surface is di- vided into two equal parts by the long palate suture, which is crossed at its posterior part by the transverse palate suture. SURFACE OF THE HEAD. 161 The posterior margin of the hard palate is concave on each side of the mouth; and from it is suspended the soft palate. The point in the centre of this margin gives origin to the azygos uvulae muscle. The foramina on this surface, are the anterior palatine or foramen incisivum, in the long palate suture just behind the in- cisor teethi and on either side, behind, between the palate and pterygoid process of the palate bone, bounded exteriorly by the upper maxillary, is the posterior palatine foramen. About one or two lines behind this, is another foramen, in the base of the pterygoid process of the palate bone, through which pass fibrillae, of the same nerve that occupies the posterior palatine foramen. The posterior palatine foramen also transmits an artery to the soft palate, the mark of whose course may be seen at the base of the alveolar processes for the molar teeth. The depth of the palatine fossa depends on the state of the teeth. When they are removed by old age, and the alveolar processes also, what was palatine fossa is almost a plane surface; and in many instances of extreme old age, entirely so, excepting the part formed by what remains of the lower jaw. The sepa- ration from the nose is also extremely thin, and not unfrequently imperfect. The transverse diameter of the mouth is much de- creased, in consequence of the absorption of the alveolar pro- cesses taking place, from the outside towards the inside. The internal surface of the lower jaw has been sufficiently de- scribed in the account of that bone. The Guttural Region of the base of the head is formed by the cuneiform process of the os occipitis, in the centre; by the infe- rior face of the petrous bones, laterally and behind; by the body and great wings of the sphenoid bone, laterally and in front; and by the several bones contributing to the orifice of the posterior nares. It is bounded anteriorly by the pterygoid fossae and openings of the nose, and behind by the mastoid and condyloid processes. It consists, consequently, in one part, which is horizontal, and in another, which is vertical. In regard to the horizontal portion, its inequalities, processes, and fossae, have been already stated. The relative position of its foramina cannot, however, be studied Vol. I,—21 162 SKELETON. except in the united bone. The following rules will afford some assistance in determining their position, even on the living body. A line passing from the anterior margin of one mastoid pro- cess to the corresponding point of the other, will subtend the stylo mastoid foramina, and the posterior margin of the foramina lacera; it will also touch the base of the styloid processes, and cut into halves the condyles of the occiput. A line, three-eighths of an inch in advance of this, run through the middle of the meatus auditorius externus, will indicate the posterior margins of the glenoid cavities,* and cut in half the inferior carotid ori- fices or foramina, and touch the anterior margins of the anterior condyloid foramina. Another line, one-fourth of an inch in ad- vance of the latter, will cut through the centre of the glenoid cavity, and subtend the styloid process of the sphenoid bone, and the bony orifice of the Eustachian tube in the temporal bone. A line passing between the external ends of the tubercles of the temporal bones, will subtend the foramina ovalia and the fora- mina lacera anteriora. The foramen spinale is about equi-dis- tant from the last two lines. The foramen lacerum anterius, being at the point of the pe- trous bone, is occasioned by the latter not filling up the space between it and the sphenoidal and the occipital bones. The de- ficiency is supplied, in the recent state, by cartilage. Precisely opposite to the point of the petrous bone, is the posterior orifice of the foramen pterygoideum, from which emerges the pterygoid nerve, and immediately divides into two branches: one going to the carotid canal, and being one of the roots of the sympathetic nerve; and the other, ascending into the cranium, becomes the Vidian nerve or superficial petrous. The vertical portion of the Guttural Region presents the pos- terior orifices of the nostrils, separated from each other by the vomer. On each side are the pterygoid processes of the sphe- noid bone, and above is its body. The pterygoid fossa, formed hetween the external and internal process, and the long unci- form termination of the latter with the broader and shorter ter- mination of the former, will also he observed. • By glenoid cavity is here meant the whole of the depression in the temporal ifeone, and not merely the surface for the condyle of the lower jaw. THE FAOK. 103 The Occipital region of the base of the head, placed imme- diately behind the other, may be considered to include the mas- toid processes, and the foramen magnum occipitis, and to be bounded behind by the tuber of the occiput and its superior transverse ridges. Its marks have been sufficiently dwelt upon, in the description of the os occipitis, The third oval will be described in detail in a short time. On the side of the head, where we consider the triangular out- line to exist, the arch formed by the malar bone and the zygo- matic process of the temporal, forms a very conspicuous feature. The anterior abutment of this arch is formed by the greater part of the malar bone, and a considerable portion of the malar pro- cess of the superior maxillary. The posterior abutment is formed by the root of the zygomatic process of the temporal bone. Its superior margin is thin, for the insertion of the temporal aponeu* rosis: the inferior margin is thick, and is divided, by a projection in its middle, into an anterior and a posterior surface, marking the origins of the two portions of the masseter muscle. There is a very considerable vacancy between the zygoma and the side of the head, occupied by the coronoid process of the lower jaw, the temporal and the external pterygoid muscles. The coronoid process is just within the zygomatic arch, and the tip rises three or four lines above its inferior margin. The large depression within the zygoma is the temporal fossa, All that portion of the side of the head beneath the ridge lead- ing from the external angular process of the os frontis, and run- ning along the middle of the parietal bone, is tributary to the temporal fossa. The bones, therefore, which form it, are the frontal, the parietal, the temporal, the great wing and the ex- ternal pterygoid process of the sphenoid bone, and the posterior face of the superior maxillary and malar bones. The arrange- ment of the squamous suture is well seen in this fossa, also the junction of the pterygoid bone with the parietal and frontal, by the overlapping of the great wing of the former. At the inferior part of the latter, is the pointed process, from which one head of the external pterygoid muscle arises. At the bottom of the temporal fossa there is a narrow slit par- 164 SKELETON. titioned from the nose by the nasal plate of the palate bone. This slit, from its position, is called the pterygo-maxillary fossa. It is triangular, the base being upwards and the point downwards. The base reaches to the bottom of the orbit. From the base there leads into the nose the spheno palatine foramen for trans- mitting the lateral nasal nerve and blood vessels. Externally to this foramen, and somewhat above it, is the foramen rotundum for the upper maxillary nerve. On a level with the spheno pa- latine foramen, and running horizontally through the base of the pterygoid process, is the pterygoid foramen for the nerve of the same name. Running vertically downwards from the angle of the pterygo-maxillary fossa, is the posterior palatine canal for transmitting the nerve and artery of the same name. The upper part or base of the pterygo-maxillary fossa, is continuous with a large fissure in the bottom of the orbit called the spheno-maxilf lary. SECT. V.—OF THE NASAL CAVITIES. The nose consists of two large cavities or fossae, in the middle of the bones of the upper jaw, and has a very irregular surface. Its cavities are separated from one another by a vertical septum, consisting in the vomer and in the nasal lamella of the ethmoid bone. This septum presents a surface which is perfectly plane, with the exception, that in some subjects it is slightly convex on one side, and concave on the other. It is deficient in front. The upper part of either nostril is formed by the cribriform plate of the ethmoid bone; in front of this the surface is very ob- lique, being made by the os nasi; posteriorly there is a vertical gutter on the body of the sphenoid bone, in the middle of which is the orifice of the sphenoidal cell. The distance between the cellular part of the ethmoid and the septum nasi is not more than three lines. The double row of foramina in the cribriform plate is very well seen, also the foramen at its anterior part for trans- mitting the nasal branch of the ophthalmic nerve; the groove formed by the latter on the posterior face of the os nasi is very distinct also. The bottom of either nostril, called its floor, is formed by the palate process of the superior maxillary and palate bones; it is NASAL CAVITIES. 165 somewhat concave, and about half an inch wide; its width, how- ever, is not uniform, as it is sometimes wider or narrower in front than it is in the middle. In it is seen the upper orifice of the foramen incisivum at the anterior point of the vomer. The external or orbitar surface of the nasal cavity is very ir- regular, presenting a number of projections and fossae, over which the Schneiderian membrane is displayed. It is formed by the upper maxillary, the ethmoid, the unguiform, the palate, the nasal, the lower spongy, and the sphenoid bones. In the middle of the posterior part of the ethmoid is the upper meatus of the nose, a deep fossa, bounded above by the cornet of Morgagni, and receiving the contents of the posterior ethmoidal cells, by one or more orifices. At the posterior termination of this fossa is the spheno palatine foramen. The middle spongy bone forms the lower boundary of the ethmoid; between it and the lower spongy or turbinated bone, is the middle meatus of the nose, a fossa of considerable size, but of unequal surface. At the fore part of the middle meatus is a vertical projection, formed by the ductus ad nasum and lachrymal canal. Just behind this ridge, is an in- terval between it and the anterior part of the ethmoid, through which the os unguis may be seen. When the middle spongy bone is broken off, immediately beneath its anterior part a chan- nel obliquely vertical, is seen in the ethmoid, which leads to the frontal sinus, through the anterior ethmoidal cell. This cell, from its peculiar shape and function, is called infundibulum. Behind this oblique channel is another oblique channel, parallel, but smaller; in which several orifices may be found of the anterior ethmoidal cells. The anterior channel has, indeed, for the eth- moidal cells other orifices besides the infundibulum, which are smaller, and below the latter. It is bounded, in front, by a sharp, thin ridge of the ethmoid, the lower extremity of which con- tributes to close the large opening into the sinus maxillare. Commonly about the middle of the middle meatus of the nose, but varying very much in different subjects, is the orifice of the sinus maxillare, or antrum Highmoranium. Its precise situation and direction are so very uncertain, that its orifice is found with some difficulty in the fresh state, in great numbers of persons. Not unfrequently I have seen this orifice high up, under the an- terior extremity of the middle spongy bone. 166 SKELETON. The inferior meatus of the nose is bounded above by the lower spongy bone, and below by the palate processes. It extends the whole length of the nostril. At the anterior part of this meatus above, is the orifice of the ductus ad nasum, which communicates with the orbit of the eye. The nostril presents an increased width, anterior to the points, where the spongy bones cease: this space is bounded on the or- bitar side by the nasal bone, and the nasal process of the upper maxilla. There is an increase of transverse diameter also at the posterior part of the nostril, behind the points where the spongy or turbinated bones cease. This space is bounded externally by the nasal plate of the palate bone, and by the internal pterygoid process. The posterior nares, or orifices of the nostrils, are oval, and are completely separated by the posterior margin of the vomer. In the dried skeleton, on the contrary, the anterior nares have a common orifice, from the deficiency of the bony septum between them. SECT VI.—ORBITS OF THE EVES. « The orbits of the eyes are the conoidal cavities in the face, pre- senting their bases outwards and forwards, and their apices back- wards ; so that the diameter of either orbit, if continued, would decussate that of its fellow in the pituitary fossa. Seven bones form the orbit, the os frontis, the os malas, the maxilla superior, the os planum, the os unguis, the os sphenoides, and the os palati. Its cavity is somewhat quadrangular, besides being conoidal. The angles are particularly well marked, in most subjects, at its base or orifice; which resembles an oblong, having its long diameter in some persons placed almost horizontally, and in others obliquely downwards and outwards. Immediately within the orifice the cavity is enlarged, owing to the projection of the orbitary ridge of the os frontis, and the elevation of the anterior inferior margin of the orbit, so that the greatest diameter is there rather vertical than horizontal. From this point the orbit decreases gradually in size to the sphenoidal fissure, or the superior foramen lacerum of the orbit which forms its apex. The internal walls of the two orbits are nearly parallel, in consequence of the cuboidal figure of the os ethmoides, which is placed between them. ORBITS OF THE EYES. 167 The superior face or roof of the orbit is triangular and con- cave; it is very thin, and presents but a slight septum between the eye and the brain. Almost the whole of it is formed by the orbitar process of the os frontis, its point only being made by the little sphenoidal wing. The depression for the lachrymal gland, at its external anterior part, is very perceptible. The trochlea for the superior oblique muscle of the eye, is also well seen about three-quarters of an inch above the point of the in- ternal angular process of the os frontis. Just at the outer side of this depression is the foramen or notch for the frontal artery and nerve. The optic foramen may be seen, very readily, pass- ing through the little wing of the sphenoid bone. The inferior face, or the floor of the orbit, is also triangular and concave, and is formed by the orbitar process of the upper maxillary bone principally; being assisted, however, at its an- terior external margin, by a portion of the malar bone; and, at its point behind, by the orbitar process of the palate bone. The latter cannot be seen very distinctly in the articulated bones, owing to its great depth in the orbit; but, when the external side of the orbit is removed with a saw, its position is placed in an interesting light. The floor of the orbit is thinner than its roof, and forms a very slight separation from the maxillary sinus. It is terminated behind by the spheno maxillary fissure, or in- ferior foramen lacerum of the orbit; a large slit, which, com- mencing at the base of the sphenoidal fissure, separates the great wing of the sphenoidal bone from the ethmoidal, the palate, and the upper maxillary bones. This fissure runs obliquely out- wards, so as to have its external extremity terminated by the malar bone. Near the external extremity is seen the com- mencement of the infra-orbitar canal, for transmitting the su- perior maxillary nerve and artery. The external face of the orbit is also triangular, and very ob- lique. It is formed by the malar bone, and by the orbitar face <©f the great sphenoidal wing. It is defined below by the spheno maxillary fissure, and above by the suture which unites the frontal to the malar, and to the great wing of the sphenoidal bone. It is terminated, at the bottom of the orfeit, hy the sphe- noidal fissure. 168 SKELETON. The internal face of the orbit is an oblong square, nearly parallel, as mentioned, with the corresponding face of the other orbit. It is formed principally by the orbitar face of the eth- moid, called the os planum, but at the apex of the orbit a small portion of the body of the sphenoid bone contributes to it, and anteriorly is the os unguis. It is bounded behind by the sphe- noidal fissure, in front by the lachrymal ridge on the nasal pro- cess of the upper maxilla, and above and below by the upper and lower ethmoidal sutures. In the upper of these sutures there are generally two, sometimes three, foramina, the anterior of which transmits an artery, a vein, and a nerve, to the nose; the posterior transmits, also, an artery and a vein to the same. The lachrymal fossa is well worthy of attention, it is seen to commence small at the upper part of the os unguis, and to in- crease in size till it is formed into a complete canal, leading to the nose, by the upper maxillary and the inferior spongy bones. The direction of the canal is almost vertically downwards,- in- clining very slightly backwards. It was stated, that the fossa in the fore part of the os unguis is sometimes supplanted by the increased breadth of the nasal process, a fact of some importance to an operator for fistula lachrymalis. SECT. VII.--OF THE FACE, TOGETHER WITH SOME REMARKS ON THE FACIAL ANGLE, AND ON NATIONAL PECULIARITIES. The anterior oval of the head extends from the frontal pro- tuberances to the base of the lower jaw, and from the malar bone of one side to the malar of the other inclusively. This oval is divided into two symmetrical or equal halves, by the vertical suture, which unites the bones of the opposite sides of the face. In the infant, the frontal protuberances are always well marked, from their being the centres of ossification for the two halves of the os frontis; in the adult, they are frequently not raised above the common level of the bone. The superciliary protuberances just above the internal half of the orbitary or su- perciliary ridges, are generally somewhat prominent, but they THE FACE. 169 vary very much in this respect in different individuals. Between these ridges the frontal bone is sometimes raised into a vertical elevation, continuous with the dorsum of the nose, as is more frequently seen in young persons. The nose, or pyramidal convexity, formed by the nasal pro- cesses of the superior maxillary, and by the nasal bones, is con- cave above, and extremely prominent below. The prominence of it depends upon the development of the ossa nasi. I have frequently seen the latter curtailed to about one-half, and even one-third, of their usual breadth, and also diminished in length; which is followed by an unusual flatness of the nose: the pecu- liarity had been presented to me till lately only in negroes; but, since then, I have also met with it in skulls of white subjects: it is, however, much more uncommon in the latter. The ante- rior orifice of the nose is cordiform, the base being below: the centre of the base is marked by a rough point, called the ante- rior nasal spine. The cheek bones form, on either side of the face, a considera- ble prominence, depending much upon the length of the malar - process of the upper maxillary bones. In savage tribes, this prominence is frequently a characteristic trait, and may depend upon the greater development of the upper maxillary sinuses, probably from the more frequent or more intense employment of the organ of smelling. The elevation of the cheek is always conspicuous in emaciated subjects, from the fat around its base being absorbed. The alveolar processes with the teeth produce, in certain sub- jects, a very conspicuous projection in the face; varying, how- ever, considerably in different individuals, and in different tribes of human beings. There is but little doubt of the organization of some men being more coarse and animal than that of others, even in members of the same family. The circumstance occa- sionally manifests itself by unusually large and long teeth, and by alveolar processes of corresponding dimensions. Savage na- tions have almost invariably thjs peculiarity, which is kept up among them, not only by hereditary influence from father to son, but also by the actual habits of the individual being productive Vol. I.—22 170 SKELETON. of, and favourable to this arrangement. It would be interesting , to know whether, from their articles of food generally being harder to masticate than such as are used by civilized people, they do not contribute to, or even produce a greater develop- ment in the organs of mastication. Analogy is in favour of the opinion, because the arms or the legs are always developed in proportion to the vigour and frequency of the exercise to which they are put. Ploughmen have large legs. Blacksmiths have large arms. Persons whose habits of exercise do not call into action any part of the body, to the exclusion of other parts, have finer and more graceful forms than labourers. It is therefore, probable, that the ease and gracefulness of movement, said to mark the polished and accomplished man of fashion, depend upon the harmonious action of his whole frame, derived from this pro- portionate development of all its parts. Besides the influence of exercise upon the organs of mastication, (he passions or faculties of the mind not unfrequently manifest themselves there. Indi- viduals of unusual ferocity and savageness, have frequently large teeth and alveolar processes. The gnashing of the teeth has, in all ages, been considered one of the most striking signs of anger. While speaking of these indications of man in a savage and uncultivated state, it will be understood that I allude to such tribes as are engaged in the chase, and in other active modes of subsistence, and whose habits are not settled down into the agri- cultural or pastoral condition. It is quite possible for one in the latter situation to be equally uninstructed, on every point of mental improvement, and to be much inferior in capacity, to one of the former; yet his articles of food, and the sensations and passions in which he indulges, will give no very prominent out- line to his face, but only mark it by the general expression of dulness and ignorance. The outline of the face is marked also by depressions or fossae. Those for the eyes and for the nose have been studied, and ar- rest at once the attention of the most superficial inquirer. Im- mediately below the orbits are the canine fossae formed in the centre of the front of the upper maxillae. Just above the incisor teeth of these bones are the superior incisive fossae. Below the THE FACE. 171 inferior incisor teeth, on each side, also, is the inferior incisive fossa. In most adults the face projects somewhat beyond the crani- um, but there is a considerable diversity in this respect between different tribes of human beings. Camper, who has paid much attention to this arrangement, has designated it under the term of the facial angle, which he marks off by two 'straight lines. One is drawn from the lower front part of the frontal bone to the point between the roots of the incisor teeth of the upper jaw; the other from this latter point to the middle of the meatus audi- torius externus, or thereabouts. The facial angle is included be- tween these two lines. In Caucasian, or European heads, this angle is about eighty degrees. In the negro, or Ethiopian, it is about seventy degrees; and in the Mongolian or copper-coloured man, about seventy-five degrees. An invariable relation is established between the extent of the facial angle, the capaciousness of the cranium, and the size of the nasal and palatine cavities. The nearer the approach is to a rectangle, the smaller is the cavity of the nose, and of the mouth, and the greater is that of the cranium, thereby manifesting a more voluminous and intellectual brain. On the contrary, the more acute that the facial angle is, the smaller is the volume of brain, and the larger are the nose and mouth. This is so fre- quently the case, that Bichat considers it almost a rule in our organization, that the development of the organs of taste and smell, is in an inverse ratio to that of the brain, and consequently to the degree of intelligence. This, like other general rules, is subject to exceptions, in con- sequence of the facial angle varying in its size, from causes which have no connexion with the degree of development of the brain. Thus an unusual prominence and thickness in the lower part of the os frontis, from an increased capaciousness of the sinuses, will make the facial angle appear less acute. The absorption of the alveolar processes, after the loss of the teeth, will produce the same result in our measurements of the facial angle. The heads of infants, previously to the appearance and full growth of the teeth, have always the facial angle less acute than the heads of adults: in some cases an angle of ninety degrees is presented in them. On the contrary, a growth of teeth, and consequently of 172 SKELETON. the alveolar processes, disproportionate to the size of the body of the upper jaw, will cause the facial angle to project very consi- derably even in an individual of the Caucasian race. Similar ob- jections may be brought against the indications of the inferior line. The fair state of this argument appears then to be, that the doctrine of the facial angle, though correct in a majority of instances, has numerous exceptions from individual peculiarities, and that there is no race of human beings which does not pre- sent the facial angle in all its ranges from seventy to ninety degrees. In regard to the various configurations of the human face and stature, depending upon habits and circumstances continued through a long succession of ages and generations, the following views of one,* pre-eminently qualified to judge, will not be unin- structive. " Although there appears to be but one human species, since all its individuals can couple promiscuously, so as to produce a prolific offspring, we yet remark in it certain hereditary confor- mations, which constitute what are called races. Of them there are three which are eminently distinct in appearance: they are, the white or Caucasian; the yellow or Mongolian; the negro or Ethiopian. " The Caucasian race, to which we belong, is distinguished by the beautiful oval form of the head; and it is this which has given birth to the most civilized nations, and to those which have ge- nerally ruled over the others. It has some differences in the shade of the complexion, and in the colour of the hair. " The Mongolian is known by its prominent cheek bones, flat face, narrow and oblique eyes, straight and black hair, thin beard, and olive complexion. It has formed vast empires in China and Japan, and has sometimes extended its conquests on this side of the Great Desert; but its civilization has always re- mained stationary. • Regne Animal, par M. le Chev. Cuvier, torn. 1, p. 94. Paris, 1817. THE FACE. 173 " The negro race is confined to the south of Mount Atlas; its complexion is black, its hair woolly, its skull compressed, nose flatfish; its prominent mouth and thick lips make it manifestly approach the monkey tribe; the people which compose this race have always remained in a state of barbarism. " The race from which we are descended is called Caucasian, because tradition and also the lineage of nations, would appear to trace it to the group of mountains situated between the Cas- pian and the Black seas, (on the borders of Europe,) from whence it has radiated in every direction. The people of Caucasus, as also the Georgians and Circassians, are considered, even at the present day, the handsomest in the world. The principal branches of this race are distinguishable by the analogies of language. The Armenian or Syrian division, directed its course towards the south, and has given birth to the Assyrians, the Chaldeans, and the untameable Arabs, who, after Mahomet, were very near be- coming masters of the world; to the Phenicians, the Jews, and the Abyssinians, who were Arabian colonies; and it is very pro- bable that the Egyptians also are descended from the same source. It is from this branch, (the Syrian,) always inclined to mysticism, that the most widely extended religions have sprung. Science and literature have flourished among them occasionally, but al- ways under fantastic forms, and with a figurative style. " The Indian, German, and Pelasgic branch, is infinitely more extended, and was divided at a much earlier period; we, never- theless, recognise the greatest resemblance between its four prin- cipal languages; which are, the Sanscrit, at present the sacred language of the Hindoos, and mother of all the dialects of Hin- dostan; the ancient language of the Pelasgi, which is the common mother of the Greek, the Latin, of many tongues which are now extinct, and of almost every language spoken in' the south of Eu- rope ; the Gothic or Teutonic, from which are derived the lan- guages of the North and North West, such as the German, Dutch, English, Danish, Swedish, and their dialects; and lastly, the lan- guage called Sclavonian, from which come those of the north- east, as the Russian, Polish, Bohemian, &c. " It is this great and respectable branch of the Caucasian race, which has carried farthest Philosophy, the Arts and Sciences, and which has been for ages the depository of them. 174 SKELETON. " This branch was preceded in Europe by the Celts, who came from the north, and were formerly very much extended, but are now confined to the most western parts; and by the Cantabrians, who passed from Africa into Spain, and are, at present, almost confounded with the numerous nations whose posterity has been blended in this peninsula. " The ancient Persians have the same origin with the Indian branch; and their descendants, even at the present day, bear the strongest marks of affinity to the European nations. " The Scythian or Tartarian branch, first directing their course to the north and north-east, always led erratic lives in the vast plains of those countries: and they have only left them to return and destroy the more comfortable establishments of their breth- ren. The Scythians, who, at so remote a period of antiquity, made irruptions into Upper Asia; the Parthians, who destroyed there the power of the Greeks and Romans; the Turks, who over- threw there that of the Arabs, and subjugated in Europe the un- happy remnant of the Greek nation, were swarms of this stock; the Finlanders and the Hungarians are colonies of it, in some measure astray among the Sclavonian and Teutonic nations. The north and east of the Caspian Sea, their original country, are still inhabited by people of the same origin, and speaking si- milar languages; but they are there intermixed with an infinity of other petty nations, of different origins and languages. The Tartar nation has always remained more unmixed in all that tract of country, extending from the mouth of the Danube, to be- yond the Irtisch, from which they so long threatened Russia, and where they have at last been subdued by her. The Mongolians, however, in their conquests have blended their blood with these people, and many traces of this intermixture are discovered, prin- cipally among the Western Tartars." " The Mongolian race commences to the east of this Tartar branch of the Caucasian, and prevails thence to the Eastern Ocean. Its branches, the Calmucks and Halkas, still nomadic or unsettled, occupy the Great Desert. Thence have their ances- tors, under Attila, under Genghis, and under Tamerlane, spread far and wide the terror of their name. The Chinese come from this race, and are not only the most anciently civilized of it, but, indeed, of any nation yet known. A third branch, (the Mont- THE FACE. 175 choux) has recently conquered China, and continues to govern it. The Japanese and Coreans, and almost all the hordes which ex- tend to the north-east of Siberia, under the domination of Russia, belong also to it in a great measure. If we except a few Chinese literati, the whole Mongolian race is universally addicted to the different sects of the worship of Fo. " The origin of this great race appears to have been in the Altay Mountains,* as ours was in the Caucasian; but it is impos- sible to follow so well the clew of its different branches. The history of those wandering people, is as fugitive as their establish- ments; and the records of the Chinese, from being confined to their own empire, afford us but short and vague accounts of their neighbouring nations. The affinities of their languages are also but too little known to guide through this labyrinth. " The languages of the north of the peninsula beyond the Ganges, and also that of Thibet, bear some affinity to the Chinese, at least, in their monosyllabic nature, and the people who speak them are not without traits of resemblance to the other Mongolian nations; but the south of this peninsula is inhabited by the Malays, a much handsomer people, whose race and language are spread over the coasts of all the islands of the Indian Archipelago, and have occupied almost all those of the Southern Ocean. On the largest of the former, especially in the uncultivated and sa- vage parts, we find other men, who have woolly hair, black com- plexion, and negro visage, and who are all extremely barbarous The most known are the Papuas, a name by which they may be generally denominated. " It is not easy to refer either the Malays or Papuas, to any one of the three great races; but can the former be plainly dis- tinguished from their neighbours, the Caucasian Hindoos on one side, and the Mongolian Chinese on the other? We must confess that we do not find them to possess sufficient characteristics to enable us to answer this question. Are the Papuas negroes, who formerly straggled along the Indian Ocean? We have nei- ther drawings nor descriptions sufficiently clear to reply to this question. " The inhabitants of the north of the two continents, the • A range in the north of Asia, about 5000 miles long. 176 SKELETON. Samoiedes, the Laplanders, and the Esquimaux, sprung, accord- ing to some authorities, from the Mongolian race. Agreeably to others, they are but a degenerate offspring of the Scythian and Tartarian branches of the Caucasian race. " It is impossible to refer, satisfactorily, the Americans them- selves to either of our races of the old continent; and yet they have not characteristics precise and constant enough to constitute a distinct race. Their copper-coloured complexion is not suffi- cient; their hair, which is generally black, and their scanty beard, would lead us to refer them to the Mongolians, did not their well marked features, and their moderately prominent noses, oppose such an arrangement; their languages are as in- numerable as their tribes, and we have yet been unable to dis- cover either any analogies among them, or with those of the an- cient world."* SECT. VIII.--OF THE DEVELOPMENT OF THE FCETAL HEAD. The foetal head, in the very early stages of gestation, forms an oval vesicle, constituting the greater part of the bulk of the em- bryo, and at this period has the face scarcely visible. The parietes of this vesicle are formed by a thin membrane, consisting of two layers, the external of which is the pericranium, and the internal layer is the dura mater. These layers adhere so closely that they cannot be accurately separated by the knife. About the third month of the embryo, or even earlier, ossifica- tion may be seen at several points of the cranium, but more ex- tensively about its base. These points are the centres of ossifi- cation, which progressively increase towards their respective circumferences, by the deposite of new bony matter. Generally the base of the cranium begins to ossify before the vault, and is entirely ossified at birth, with the exception of a few parts, as the clinoid processes and the ethmoid bone. The following nuclei of ossification show themselves between * On this subject, see also Lectures on the Physiology, Zoology, and Natural History of Man, by W. Lawrence. London, 1822. Dictionnaire des Sciences Med. tome XX[. Paris, 1817. Histoire Naturelle de L'Homme, par Lacapede. Paris, 1821. Blumcnbach de Variet. Gen. Hum. Nat. 1794—also Decades, 1790—1814, FCETAL HEAD. 177 the laminae of the foetal cranium, from the third to the fourth month. One at the anterior part, for the centre of either side of the os frontis; one for the centre of each parietal bone, on the upper side of the head; one on the side of the head below, for the squamous portion of the temporal bone; and there are se- veral for the occipital bone. These points extend themselves in radii; and, as the intervals between the latter become wider by their divergence, new radii, as observed elsewhere, are deposited between them. In some of the bones, the radii, from opposite points, in the progress of ossification before and after birth, meet and coalesce: this occurs in the os frontis and in the os occipitis. At birth the contiguous margins of the flat bones simply ap- proach each other, but have not interlocked. These bones con- sist then of but one table, the edges of which are very finely ser- rated, and thereby show the radii of ossification. The edges are held together by the dura mater, internally, and the pericranium, externally; but the fissure between them is very obvious, and so large that it allows very readily considerable motion and the mounting of one bone upon the other by slight pressure. It is always to be observed that the base of the cranium is an ex- ception to the latter rule, both from the breadth of its articulating surfaces, and from its comparatively advanced ossification. In parturition, therefore, the vault of the cranium, by its mobility, is adjusted to the contour of the pelvis, but the base does not yield in either of its diameters to the expulsive powers of the uterus. The latter provision, however inconvenient in parturition, is of the greatest consequence immediately afterwards; for without this immobility in the base of the cranium, whenever the weight of the head was thrown upon it, the pressure of the vertebral column would drive it upwards, to the injury of the brain and of the nerves proceeding from it. This resistance, it may be added, is still farther assisted by the arched figure of the base of the cranium. On this subject, it is not a little remarkable, that even the heads of hydrocephalic foetuses have the bones of the base fully ossified, and in contact, so as to support the weight of the head in the vertical position. Fontanels.—In consequence of the flat bones of the cranium ossifying always towards the circumference, their angles, as ob- served, being the longest radii from their centres, are the last in Vol. I.—23 178 SKELETON. ossifying. These angles are commonly incomplete at birth, and the membranous spaces which represent them are the Fontanels. Of these there are six, two on the middle line of the head, above, and two on either side. The former afford highly important in- dications to the midwife. The anterior fontanel is the largest of all. It is at the fore part of the sagittal suture, and is produced by a deficiency in the angles of the parietal bones, and of the contiguous angles of the os frontis. It is quadrangular or lozenge-shaped; and the anterior angle is generally longer than the others. This is re- markably the case, when the sagittal suture is continued down to the root of the nose. The posterior fontanel is at the other extremity of the sagittal suture, and as there are only three points of bone defective there, two for the parietal bones, and 4 one for the occipital, this suture is triangular. In many children, at birth, it is so far filled up as to be scarcely visible; the three membranous sutures, however, which run into it, make its posi- tion sufficiently discernible by the finger. Of the two fontanels, on either side, one is placed at the angle of the temporal bone where it runs up between the occipital and the parietal. The other is in the temporal fossa, under the tem- poral muscle, at the junction between the parietal and the sphe- noidal bones. These two fontanels are but little referred to by the accoucheur in delivery, as they are irregular and indistinct. The pulsations of the brain may be readily felt through the fon- tanels. They ossify rapidly after birth, and are frequently closed completely by the end of the first year; but if there be an accu- mulation of water in the ventricles of the brain, they remain open for an indefinite period. The longest diameter of a child's head is from the vertex or posterior extremity of the sagittal suture to the chin, and mea- sures five inches and a quarter. From the middle of the frontal bone to the tubercle of the occipital are four inches, from one parietal protuberance to the other is about three inches and a half. At birth, the os frontis consists, most commonly, of two pieces, united by the sagittal suture. The parietal bone is a single piece, incomplete at its angles. The temporal bone consists of three pieces: one is the squamous, the other is the petrous, and HYOID BONE. 179 the third is a small ring which afterwards constitutes the meatus externus; it is deficient in styloid and mastoid processes. The os occipitis is in four pieces: one extends from the angle of the lambdoidal suture to the upper edge of the foramen magnum; on either side of the foramen magnum is another, with the con- dyle growing on it, and the cuneiform process is the fourth. The ethmoid bone is cartilaginous. The sphenoidal bone is in three pieces. The body and little wings, being united, form one; the great wing and the pterygoid process, being also united, form on either side of the body another piece. At birth there is a great disproportion in size between the cra- nium and face. This disproportion diminishes in the progress of life, by the development of the sinuses and of the alveolar pro- cesses in the latter. At birth, indeed, there is no cavity either in the sphenoidal, the frontal, or the upper maxillary bones; the orbitar and the palate plates are very near each other, and the rudiments of the teeth are hidden in the bodies of the upper and lower jaw bone. The latter consists of two pieces, united by cartilage at the chin, and its angle is very obtuse. CHAPTER IV. THE HYOID BONE, (OS HYOIDES, HYOIDE.) The Os Hyoides is placed at the root of the tongue, within the circle of the lower jaw. It is an insulated bone, having no connexion with any other, except by muscles and ligaments. It is said, very properly, to resemble the letter U, and consists of a body and two cornua. The body is in the middle; it is the largest part of the bone, and forms nearly a semicircle. Its anterior face is convex, and its upper part is flattened by the insertion of the muscles from the lower jaw. The posterior face is concave. The cornua, one on either side, are about an inch long, and are placed at the extremities of the body, being united to it by the interposition of cartilage and ligamentous fibres. They are somewhat flattened rather than cylindrical, and diminish to- 180 SKELETON. wards the posterior extremities, where they terminate in a round enlargement like a head. At the cartilaginous junction of the cornu and body, on each side, there is a small cartilaginous body three or four lines long, fastened by ligamentous fibres. It is frequently found ossified. This is the appendix or lesser cornu. A round ligament passes from it to the extremity of the styloid process. The texture of this bone is cancellous, with a thin lamina externally. M. Portal says, that he has found it carious from venereal contamination; in which case, the patient had been af- flicted with violent sore throat and purulent expectoration. Sau- vages and Valsalva have met with.a case, where, from luxation of the cornu, the patient spoke with great difficulty. The liga- ment to the styloid process is, in some rare instances, ossified to a considerable extent, which produces difficulty in swallow- ing and in talking. CHAPTER V. OF THE UPPER EXTREMITIES. This portion of the skeleton is divided, on either side of the body, into shoulder, arm, fore arm, and hand. SECT. I.--OF THE SHOULDER. The shoulder consists of two bones, the clavicle and the sca- pula, and occupies the superior, lateral, and posterior part of the thorax. Its shape and position are such, that it augments con- siderably the transverse diameter of the upper part of the trunk taken as a whole: while the thorax alone, at this place, is actu- ally smaller than it is below. The clavicle is longer, in pro- portion, in the female than in the male, which increases the transverse extent of the shoulder, and gives a greater space on the front of the thorax for the development of the mammse. This coincidence between the length of the shoulder and the THE SHOULDERS. 181 development of the mamma, has been particularly noticed by Bichat, who says that it is almost always well marked, that very rarely a voluminous bosom reposes on a small pectoral space, or a small bosom is found upon a large pectoral space. In the male, on the contrary, this diameter of the trunk is increased principally by the breadth of the scapula, which, from its po- sition on the thorax, and its great size, gives the bulky appear- ance to this part. It is evident that these modifications in the frame-work of the shoulder are connected with the natural des- tinations of the two sexes. In woman the length of the clavi- cle is adverse to its strength, and it is indistinctly marked 'by muscular connexions; whereas, in man it is short, strongly marked, and large. Anatomists who are fond of extending such comparisons, say, also, very justly, that the pubes, which per- form the same office for the lower extremities that the clavicles do for the upper, that of keeping the two apart, are, in the fe- male, both smaller and longer than in the male; that their shape is not so favourable to strength or locomotion, and has a special view towards the lodgement of the genital organs, and to the passage of the child. In man the increased size of the whole skeleton, and the greater development of the muscular system, indicate that he was intended for more laborious exertion than the female. The thorax and the shoulder are connected by a reciprocal development, both being indicative, when large, of a robust and vigorous constitution, and when small, of a weakly one. As both of these parts are acted on by the same muscles, the neces- sity of this coincidence is sufficiently apparent. The height of the shoulder depends upon the scapula alone; its elevation, therefore, is greater in males and in vigorous persons generally, than in females and in weakly individuals. The direction of the shoulder is such, that the articular face of the scapula for the os humeri, looks outwards, thereby proving that the quad- ruped position in man is unnatural; for by it, the weight of the fore part of the trunk is directed upon the back part of the cap- sular ligament of the joint instead of upon the glenoid cavity, as in quadrupeds. This, and many other circumstances, prove that the natural intention of the upper extremities in the human subject, is to seize upon objects, and not to maintain the hori- zontal position. 182 SKELETON. Of the Shoulder Blade, (Scapula, Omoplale.) The Scapula is placed upon the posterior superior part of the thorax, and extends from the second to the seventh rib, inclu- sively; its posterior edge is nearly parallel with the spinous pro- cesses of the vertebrae, and not far from them. Its general form is triangular. It therefore presents two faces, of which one is anterior, and the other posterior,—three edges, of which one is superior, another external, and the third inter- nal or posterior—and three angles, of which one is superior, another inferior, and the third exterior or anterior. The posterior face of the scapula, or its dorsum, is somewhat convex, when taken as a whole; and is unequally divided by its spine into two surfaces or cavities, of which the lower is twice or three times as large as the upper. The spine is a very large process that begins at the posterior edge of the bone, by a small triangular face; rapidly increases in its elevation, and running obliquely towards the anterior angle, ceases somewhat short of it; it is then elongated forwards and upwards, so as to overhang the shoulder joint, and to form the acromion process. The ca- vity above the spine is owing principally to the elevation of the latter, and is called the fossa supra-spinata; it is occupied by the supra-spinatus muscle. The cavity below the spine is the fossa infra-spinata, and is for the infra-spinatus muscle: it is bounded below by a rising of the external margin of the bone. The middle of this fossa presents a swell or convexity, which is a portion of the general convexity presented by the posterior face of the bone. The spine of the scapula is always promi- nent in the outline of the shoulder, and has a well secured base along the whole of its attachment to the bone, to where it ter- minates in the acromion process. It leans upwards, and from the increased breadth of its summit, is concave both above and below. The summit itself is somewhat rough, and has inserted into its superior margin the trapezius muscle, while the infe- rior margin gives origin to the deltoid. The little triangular face at the commencement of the spine is made by the tendon of the trapezius muscle gliding over it. The acromion process arises from the spine by a narrow neck, is triangular, nearly horizontal, and overhangs the glenoid cavity, being elevated THE SHOULDERS. 183 about one inch above it. It is slightly convex above and concave below: the external and the internal margins are the longest. The posterior margin is continuous with the inferior edge of the spine; and the internal is on a level with the clavicle. At the fore ex- tremity of the internal, is a small, oval, articular face, by which the acromion unites with the clavicle. The margins of the acro- mion, with the exception of the internal, are rough, and give origin to the deltoid muscle. The anterior or costal face of the scapula is concave, and ob- tains the name of the sub-scapular fossa or venter. It is occu- pied by the sub-scapular muscle; the divisions of which, by leaving deep interstices between them, produce corresponding ridges upon the bone, that run obliquely upwards and outwards. Along the whole posterior margin of the scapula, is inserted the serratus major anticus. The posterior or vertebral margin of the scapula is the long- est of the three, and is called the base. It is not perfectly straight, but somewhat rounded, especially above the spinous process; and has there varied degrees of obliquity in different persons. This margin, below the spine, receives the rhomboi- deus major muscle, and above the spine, the levator scapulae; at the part between the other two, the rhomboideus minor is in- serted. The external or axillary margin of the scapula, also called the inferior costa, is much the thickest of the three. A superficial fossa, beginning about two inches from its inferior extremity, and running up to the neck of the bone, lodges the teres minor muscle. On the exterior face of the inferior angle is a flat sur- face, from which the teres major muscle and a slip of the latis- simus dorsi arise. At the fore part of this surface the inferior costa is elongated into a kind of process. Just below the gle- noid cavity is a small ridge for the origin of the long head of the tricejis muscle. The superior margin or costa of the scapula, is the shortest and thinnest of the three, and is terminated in front by the co- 184 SKELETON. racoid notch between it and the coracbid process. The notch is converted into a hole by a ligament, in the living state, and through it pass the upper scapular nerve and blood vessels. The glenoid cavity for articulating with the os humeri, sup- plies the place of the anterior angle of the scapula. It is very superficial, and ovoidal, with the small end upwards. Just at the upper end is a small flat surface, from which the long head of the biceps arises. The glenoid cavity is fixed on the cervix, as it is called, at which a general increase in the thickness of the bone occurs, in order to give a strong foundation to this cavity. From the superior part of the cervix arises the coracoid'pro- cess, the base of it being bounded, in front, by the glenoid cavi- ty, and behind by the coracoid notch. The base r.ises upwards and inwards for half an inch, and what remains of the process, then, runs horizontally inwards and forwards, to become small- er, and terminate in a point. This point is advanced beyond the glenoid cavity, about an inch from its internal margin. The upper surface of the coracoid process is rough and undulated; below it is concave, forming an arch under which passes the sub-scapularis muscle. On the clavicular side of its base is a tuberosity, from which arises the conoidal ligament. The ex- tremity is marked by three surfaces: the interior is for the in- sertion of the pectoralis minor, the middle for the origin of the coraco-brachialis, and the external for that of the short head of the biceps. The acromial margin of the coracoid process gives origin to the triangular ligament of the scapula, which is insert- ed into the acromion just below the face for the clavicle. The scapula is composed of cellular and compact substance. The two laminae of the latter are in contact in the fossa supra- spinata, and infra-spinata; from which cause the bone is diapha- nous at these points. Of the Clavicle, (Clavicula, Clavicule.) The Clavicle is a long bone, situated transversely at the up- per front part of the thorax, and extends from the superior ex- tremity of the sternum to the acromion of the scapula. It is cylindrical in fts middle third, flattened at its external, and pris- THE ARM. 1S5 matic or triangular at its sternal extremity. Besides being shorter, it is more crooked and robust in man than in woman, and different individuals present it under considerable varieties of curvature. The sternal two-thirds of it, are convex in front, and concave behind, while the humeral third is concave in front, and convex behind; this double curvature induces anato- mists to compare it with the letter S, though it is by no means so crooked. ., We have to consider its superior and inferior face, its ante^. rior and posterior edge, and the two extremities. The superior face is smooth, and does not present any marks of importance excepting a depression near the sternum, for the origin of the sterno-cleido mastoid muscle. The inferior face, near the ster- nal end, has a rough surface,-to which is attached the costo-cla- vicular or rhomboid ligament: about fifteen lines from the hu^ meral extremity is a rough tuberole for the attachment of the coraco-clavicular or conoid ligament. Between the two ends, a superficial fossa is extended for lodging the sub-clavius mus^ cle. The sternal two-thirds of the anterior margin are marked by the origin of the pectoralis major; it is there thick: the other part of this margin is thinner, and gives origin to the deltoid muscle. The posterior margin presents, near its middle, one or more foramina for the nutritious vessels. The triangular inter- nal end of the clavicle is unequal where it joins the sternum, and is elongated considerably at its posterior inferior corner, The external flat end presents at its extremity a small oval face, corresponding with that on the acromion scapulae. This bone is very strong from the abundance of its condensed lamellated structure; but, like other round bones, the cellular matter predominates at its extremities. sect, ii.—of the arm, (Os Humeri, L'Humerus.) The arm extends from the shoulder to the elbow, and has but one bone in it, the os humeri. The latter, in its general appear- ance, is cylindrical, with an enlargement of both extremities; the superior end presents a general swell, while the inferior is flattened out. The superior extremity of the os humeri, which is also called Vol. I.—24 186 SKELETON. its head, is very regularly hemispherical, and has its axis di- rected obliquely upwards and backwards, to apply itself with more facility to the glenoid cavity of the scapula. The base on which the head reposes is termed neck, it is not more than four or five lines long, and is marked off by a superficial furrow, sur- rounding the bone. This furrow is more conspicuous above, where it separates the head from two knobs called the tuberosi- ties. One of these tuberosities, the external, being placed beneath the acromion scapulae, is much larger than the other, and bears on its upper face the marks of the tendinous insertion of three muscles. The most internal mark is for the supra-spinatus sca- pulae, the middle for the infra-spinatus, and the external, or pos- terior, for the teres minor. The smaller tuberosity is internal, and placed on a line with the coracoid process; it has but one mark, and that is on its Upper face, for the tendinous insertion of the sub-scapularis muscle. The two tuberosities are sepa- rated by a deep fossa, named bicipital, from its lodging the ten- don of the long head of the biceps muscle. This fossa is con- tinued, faintly, for some inches down the os humeri; its lower part being bqunded, externally, by a rough ridge, indicating the insertion of the pectoralis major, and internally by another ridge, not quite so strong or rough, indicating the insertion of the teres major and latissimus dorsi. The body of the os humeri is the part extended between its extremities. The superior half presents a more cylindrical ap- pearance than the inferior, which is rather triangular. On the middle of the bone, externally, two inches below the insertion of the pectoralis major, exists a triangular elevation into which the deltoid muscle is inserted. At the internal margin of the bone, and on a line with the latter, is the insertion of the coraco- brachialis muscle; and between the two is the orifice of the canal for the nutritious artery. The front of the os humeri, in its lower half, is flattened on each side down to its inferior end; on these surfaces is- placed the brachialis internus muscle. On a line with the posterior end of the greater tuberosity, and a lit- tle below it, an elevation is formed for the origin of the second head of the triceps extensor cubiti. The posterior face of the THE ARM. 187 bone is flattened from this point down to its lower extremity, and accommodates the last named muscle. The articular surface for the elbow joint is very irregularly cylindrical. The part that joins the radius, presents itself as a small hemispherical head, placed on the front of the bone, and with its axis looking forwards. Just above it, in front, is a small depression for the head of the radius in its flexions. The surface which is in contact with the ulna, is more cylindrical, but still irregularly so; for its middle is depressed, while the sides are elevated: the internal side is much broader and more elevated than the external. The lesser sigmoid cavity is just above the front of the ulnar articular surface, and receives the coronoid process. The greater sigmoid cavity is in a corre sponding place behind, and receives the olecranon process: the bone which separates these cavities is very thin;#sometimes it is even deficient. The external condyle is just above the radial articular surface; it is continuous with a ridge of three or four inches long, form- ing the external margin of the bone, and from it, and the ridge together, arise the extensor muscles of the fore arm and hand. The ridge, itself, is bounded, above, by a small spiral fossa, de- scending downwards and forwards, made by the spiral artery and the muscular spiral nerve. The internal condyle is placed just above the internal margin of the ulnar articular surface: it is much more prominent and distinct than the external, and may be readily felt beneath the skin. A ridge also leads from it, and extends upwards as high as the insertion of the coraco-brachialis, but it is by no means so elevated as the external ridge, though it is much longer. From the internal condyle, and the adjoin- ing part of the ridge, arises the flexor muscles of the hand and fore arm. The os humeri is composed of compact and cancellated sub- stance; the latter predominates atthe extremities, and the former in the body. 188 SKELETOX. SECT. III.--OF THE FORE ARM> The fore arm is placed between the arm and the hand and consists in two straight bones, the Ulna and the Radius, of which the former is on the same side with the little finger, and the latter on that of the thumb. f Of the Ulna, (Cubitus^) The ulna, though nearly straight, is not wholly so. It is much larger at the upper than at the lower extremity, and in its general features is triangular. It has to be considered in its humeral and carpal extremities, and in its body. The humeral, or upper extremity, presents the olecranon pro^- cess at its termination, the coronoid, a little below and in front; the greater sigmoid cavity between the two; and the lesser sig- moid on the radial surface of the coronoid. The olecranon process is rough on its upper face, for the in- sertion of the triceps muscle, and terminates in front in a sharp edge and point, which are received into the greater sigmoid ca* vity of the os humeri. The coronoid process is a triangular, sharp ridge, much elevated, and having a large base; on the lower front of the latter is a roughness for the insertion of the brachialis internus muscle. The greater sigmoid cavity forms all the articular surface between the margins of the two pro- cesses. It is divided, transversely, at its bottom by a superficial roughness, which distinguishes the olecranon from the coronoid portion of it. Besides which, a rising exists in its vertical length, which is received into the corresponding depression of the os humeri. The lesser sigmoid cavity has its surface con- tinuous with that of the greater, and presents itself as a small semi-cylindrical concavity, for articulating with the side of the head of the radius. A small fossa, for fatty matter, exists just above it. The carpal, or lower extremity of the ulna, presents, on tire THE FORE ARM. 189 side of the little finger, a process of variable length, the sty- loid, from which arises one of the lateral ligaments of the wrist. At the radial side of this process is an articular face or small head, one surface of which looks towards the wrist, and the other is in contact with the radius, being semi-cylindrical. On the back of the ulna, between the styloid process and this head, is a groove for the passage of the extensor carpi ulnaris. The body of the ulna is triangular, in consequence of three ridges, which extend from the brachial to the carpal extremity. The most prominent of these ridges is on its radial side, and, beginning at the posterior end of the lesser sigmoid cavity, con- tinues very distinct almost to the lower end; it then, however, gradually subsides. From it arises the interosseal ligament. Within this ridge, on the anterior or palmar face of the bone, is another, more rounded, which, beginning at the internal mar- gin of the coronoid process, extends down to the styloid pro- cess. For the greater part of its length it gives origin to the flexor profundus digitorum, but just above the carpus, the pro- nator quadratus arises from it. The third ridge begins at the external margin of the olecranon, and runs in a serpentine way to the inferior end of the ulna, but becomes almost indistinct at its lower part. To the upper fourth of this ridge, is attached the anconeus muscle, which reposes in a hollow between it and the beginning of the first or outer ridge. To the beginning of Shis latter ridge, is attached the supinator radii brevis muscle. On the posterior surface of the bone, just below the olecra- non, is a long sub-cutaneous triangular face on which we lean. The three ridges of the ulna divide it into as many surfaces, which are each modified by the muscles lying upon them. The anterior surface presents, just above the middle of the bone, the canal for the nutritious artery, running obliquely upwards. The body of the ulna is compact, the extremities, and more ■abundantly the upper, are cancellated. 190 SKELETON. Of the Radius, (Radius.) The radius is shorter than the ulna, is placed on its external side, and extends from the os humeri to the wrist. It is smaller at the humeral than at the carpal extremity, and though nearly straight is somewhat convex, outwardly. It is to be considered in its extremities and body. The superior or humeral extremity presents a cylindrical head, which bears all around it the marks of a cartilaginous in- crustation, broader on the cubital than on the other side. The broader part plays in the lesser sigmoid cavity of the ulna, while the other is in contact with the annular ligament. A superficial fossa also exists on the upper surface of this head, which re- ceives the convexity of the articular face of the external con- dyle of the os humeri. The head of the radius is placed upon a narrow part called the neck, of about half an inch in length. Immediately below the neck, on the ulnar side, is a rough pro- tuberance, the bicipital, for the insertion of the biceps flexor cubiti. The lower or carpal extremity of the bone, is augmented con- siderably in volume, and is flattened out transversely. The car- pal surface presents a long superficial cavity, bounded external- ly by the styloid process; from which proceeds the external lateral ligament, and on its ulnar side, by a small cylindrical concavity, for receiving the lower end of the ulna. The for- mer or superficial cavity is divided into two by a slight ridge in its short diameter; the division next the styloid process receives the scaphoid bone, and the other the os lunare. At this extremity also a ridge exists on the front of the bone for forming the margin of the articular face, and giving origin to the capsular ligament. The posterior and external faces of the bone, here, are rendered irregular by several grooves and ridges. The large groove next to the cylindrical concavity for the ulna, transmits the tendons of the extensor communis digi- torum and indicator, also the tendon of the extensor major pol- licis, which forms a channel somewhat distinct, and on the sty- THE HAND. 191 loid side of the groove. Next to this is another large groove for the tendons of the extensor carpi radialis brevior and lon- gior; and on the styloid side of the radius is the third groove for transmitting the tendon of the extensor minor pollicis, and of the extensor ossis metacarpi pollicis. The anterior margin of this groove is formed by a small spine or ridge, into which is inserted the tendon of the supinator radii longus. The body of the radius is somewhat triangular, and therefore presents three ridges. One, on its ulnar side, extends from the bicipital protuberance to the lower end, and gives origin to the interosseous ligament; it is sharp and well marked. Another, on the outer or styloid margin of the bone, which also begins at the bicipital protuberance, and terminates in the styloid process. The upper part of this ridge is curved, has the supinator brevis inserted into it, and a portion of the flexor digitorum sublimis arising from it; at its lower part the pronator quadratus is in- serted. The third ridge is on the posterior face of the radius, and, arising insensibly from below its neck, is principally con- spicuous in the.middle third of the bone: it runs down, however, to the carpal extremity, and, becoming more prominent there, separates the two larger grooves from each other. This ridge is shorter, and not so elevated as the other two. These three ridges form as many surfaces to the radius, of which the anterior, augmenting gradually in its descent, affords attachment to the flexor longus pollicis above, and to the pro- nator quadratus below; at its upper part is the canal, slanting upwards, for the nutritious artery. The posterior surface has the extensor muscles of the thumb and the indicator lying upon it. The external surface presents a roughness, just above its middle, for the insertion of the pronator teres; and below, it is covered by the radial extensors, which are crossed by the ex- tensor metacarpi pollicis and the extensor minor. The body of the radius is compact; its extremities are can- cellated. SECT. IV.--OF THE HAND. The hand consists of carpus, metacarpus, and phalanges, and has in its composition twenty-seven bones, to which number may be added the two sesamoids. 192 SKELETON. Of the Carpus, (Carpe.) The carpus, or wrist, is next to the bones of the fore arm. Eight bones compose it, which are arranged into two rows, one adjoining the fore arm, and the other the metacarpus:—they are called first and second rows. These bones present very diversified forms, and a number of articular faces, which render them difficult to be distinguished from each other. The first or antibrachial row has in it the os scaphoides, lu- nare, cuneiforme, pisiforme. The second or metacarpal row has in it the os trapezium, trapezoides, magnum, and unci- form e. Of the Scaphoides, (Scaphoide.) This bone is on the styloid half of the end of the radius, and is distinguishable in a set by its greater length. It is convex above and concave below. The convexity forms only a half of its upper surface, the other half being rough, and making a knob at its extremity. The concavity on the lower surface is large enough to receive the end of the finger. Between the concavity and the convexity, and on the dorsal surface of the bone, at its outer end, is a second convexity, of an oblong shape. Between the two convexities is a small fossa for the capsular ligament. The palmar, or anterior face, shows a crook in the bone. The knobbed extremity projects beyond the styloid pro- cess of the radius. The other extremity, which is narrow, joins the os lunare. Of the Lunare, (Semilunaire.) This bone is at the ulnar side of the preceding, and may be distinguished by the semi-lunated shape of the surface joining the scaphoides. Its upper surface is convex where it articulates with the radius; the lower face is concavely cylindrical. The ulnar side is a plain surface which joins the os cuneiforme. Its- dorsal side is rather thinner than its palmar. THE HAND. 193 Of the Cuneiforme or Pyramidale, (Pyramidal.) This bone is placed at the ulnar side of the last, is somewhat larger than it, and may be distinguished by its representing somewhat a triangular pyramid. The surface next the lunare is plane, but the other extremity, being the boundary of the wrist in that direction, is rough. ^ Above, it presents a small convexity, adjoining the surface for the lunare, whereby it en- ters partially into the upper wrist joint. Its inferior surface is concavo-convex, the convexity being towards the ulnar end. On its palmar side it presents a circular plane surface for the os pisiforme. Of the Pisiforme, (Pisiforme.) This bone is placed on the front or palmar surface of the last, and may be distinguished by its being smaller than any other in the carpus, by its spheroidal shape, and by its presenting but one articular face, which corresponds with one on the cunei- forme. It is always so prominent as to be felt, without difficul- ty, at the ulnar extremity of the wrist, and is very moveable. Of the Trapezium, (Trapeze.) This bone is placed at the radial end of the second row; its shape is exceedingly irregular, but it may be generally distin- guished by being a bone of the third magnitude as regards the second row. It is better for the student to find out first the surface by which it articulates with the metacarpal bone of the thumb, which he can do in a short time by a comparison of the surfaces of the two bones. This being successful, will estab- lish a clew to the other surfaces, and to the relative position of the bone. The thumb surface is a concave cylindrical trochlea, placed on the radial side of the trapezium, and looking down- wards and outwards. On the reversed or upper side is a small concavity, which receives the dorsal convexity of the scaphoid bone. Continuous with this concavity is another on the ulnar side, which receives a corresponding convexity of the trape- Vol. I.—25 194 SKELETON. zoides. Between this concavity and the one for the thumb is a small plane surface, by which the trapezium articulates par- tially with the metacarpal bone of the fore finger. The dorsal face is rough and unequal. The palmar face is unequally di- vided by a high ridge or process, at the ulnar side of whose root is a deep fossa for the tendon of the flexor carpi radialis. Of the Trapezoides, (Trapezoide.) It is placed at the ulnar side of the last bone, and is the smallest in the second row. There is no liability of confound- ing it with any other bone of the carpus, as it is the least of any, excepting the pisiforme. The greater difficulty is the ad- justment of it in the separated bones: the following rule, how- ever, will serve. It is surrounded by articular faces on its sides, but the dorsal surface presents a broad base, while the palmar extremity is reduced in size. Holding the bone with a refe- rence to these, it will be observed that one side is very crook- ed and concave, while the reversed or opposite one is convex. The latter fits against the surface of the trapezium which has been indicated, while the former embraces the side of the os magnum just below its head. The metacarpal surface of the trapezoides is long and elevated in its middle for being received into the root of the metacarpal bone of the fore finger, while the upper surface presents a long concavity for receiving a part of the dorsal convexity of the scaphoides. Of the Magnum, (Grand Os.) It is placed at the ulnar side of the trapezoides, and, from its being larger than any other bone in the carpus, will scarcely be mistaken. Its ulnar side is flat, and presents a plane surface for articulating with the unciforme. The radial side is uneven and rather indistinctly marked where it joins the trapezoides, but the latter surface will be found near the middle of this side just below the head. The upper surface of the magnum is formed into a spherical head, the radial side of which reposes in the concavity of the scaphoides, while the ulnar side is in the concavity of the lunare. Its metacarpal surface is oblong, con- THE HAND. 195 vex, and winding, by which it joins the metacarpal bone of the middle finger. On the radial side of this surface is a small one continuous with it, whereby the magnum articulates partially with the metacarpal bone of the fore finger. The posterior or dorsal face is broad, while the palmar is more narrow. Of the Unciforme, (Os Crochu.) It is placed at the ulnar side of the magnum? is nearly of the same size, but readily distinguishable from it by its long crooked process as well as by its peculiar shape. Its radial side is plane where it joins the magnum; the reversed or ulnar side is brought to a thin edge. The metacarpal surface presents two distinct concavities; the one next to the ulnar edge is for the metacarpal bone of the little finger, and the other for that of the ring finger. The upper surface is convex and winding, having its ulnar mar- gin almost touching the surface of the metcarpaj bone of the lit- tle finger. The most considerable portion of the upper surface reposes upon the cuneiforme, and the remainder upon a part of the concavity of the lunare. The posterior face is broad and rough, while the palmar is narrower. From the ulnar side of the latter, projects the unciforme process already alluded to. The two ranges of carpal bones, thus fashioned, present, when articulated or united together, an oblong body, the greatest dia- meter of which is transverse. Its posterior face is semi-cylin- drical and arched, while the anterior face is concave for the passing of the flexor tendons. Two protuberances are found on each extremity of the palmar surface. Those at the ulnar end are the pisiforme, and the unciform process of the unciforme; those at the radial end are the protuberance at the radial end of the scaphoides and the sort of unciform process from the trape- zium bounding the radial margin of its groove. These several prominences may, with a little attention, be readily distinguished beneath the skin. The superior face of the carpus, which ar- ticulates with the lower end of the radius and ulna, presents an oblong convex head formed by the scaphoides, the lunare, and very partially by the cuneiforme. The inferior face of the car- pus presents a very diversified surface, subdivided into five dis- 196 SKELETON. tinct ones, each of which is fashioned according to the shape of the metacarpal bone with which it has to articulate. The central joint of the wrist, formed between the two rows of bones, is very deserving of attention. The first row is con- vex on its radial end, the convexity being formed on one half. of the scaphoides: to the ulnar side of this there is a deep con- cavity formed by the other half of the scaphoides,—by the lu- nare and the cuneiforme. The upper surface of the second row fits very accurately upon the lower surface of the first: its radial end is, therefore, a concavity formed by the trapezium and tra- pezoides, which receives the convexity of the scaphoid; then a very large prominent head is formed by the magnum and unci- forme, and received into the concavity of the first row. The magnum reposes upon the scaphoides and part of the lunare, the unciforme upon the remainder of the lunare, and the whole of the cuneiforme. The carpal bones consist of cancellated matter enclosed by condensed lamellated substance. Of the Metacarpus. The metacarpus, is situated between the carpus and the pha- langes of the fingers and thumb. It consists of five bones, one for the thumb and one for each finger. The latter are parallel or nearly so with each other; but the first diverges considerably, and is so placed as to traverse the others in front during its motions. These bones are rounded in their middle, and enlarged at their extremities. That of the thumb is the shortest, the others decrease successively in length from the fore to the little finger. Of the First Metacarpal Bone, or that of the Thumb.— It is placed upon the trapezium: besides being the shortest, is also the thickest of any. Its carpal surface is cylindrical and slightly concave from side to side, to present a fit surface to the trapezium. Its lower face is slightly convex, and elongated in front into a trochlea, on either side of which reposes a sesamoid bone. The posterior face of its body is flat and straight; the anterior is concave in its length, and is divided into two sur- THE HAND. 197 faces by a middle ridge. A roughness exists on either side, at its lower end, for the attachment of the lateral ligament. Of the second Metacarpal Bone, or that of the Fore Finger. —The greater length of this bone gives it a distinctive character. It is placed upon the trapezoides, so as to articulate laterally, also, with the trapezium, and the magnum. Its carpal face presents, in the middle, a deep concavity for receiving the trapezoides, at the radial side of which is a small plane face for articulating with the trapezium, and at the ulnar side an oblong surface, the upper margin of which joins the magnum, and the remainder is in contact with the third metacarpal bone. The lower end pre- sents a convex head extended in front to concur in the flexion of the finger, on each side of which head is a concave rough surface for the lateral ligament. The posterior face of the bone presents a triangular flat surface, the base of which is towards the finger or phalangial end. The palmar face is concave, lon- gitudinally, and divided by a middle ridge, into two surfaces, each of which is compressed by the interosseous muscles. A tubercle exists on the back of the bone just below its metacarpal end for the insertion of the tendon of the extensor carpi longior, and another in front for that of the flexor radialis. Of the Third Metacarpal Bone.—This is but slightly shorter than the last, and is nearly of the same size, but its carpal ex- tremity is very different. The latter is triangular, and is bound- ed on its radial side by a sort of styloid process, with a tuber- cle on the posterior face of it, into which the tendon of the extensor radialis brevior is inserted. It is placed upon the magnum, to which it joins by a slightly concave, winding sur- face. It also presents, continuous with the same surface, an ob- long face which joins the second metacarpal bone, and, on the reversed side, two round facets, which are contiguous to the fourth metacarpal bone. In regard to its lower or phalangial extremity and body, this bone resembles closely the one last described. Of the Fourth Metacarpal Bone.—This bone is placed upon the unciforme, and has a very small articulating surface with 198 SKELETON. the magnum: it is much smaller and shorter than the third metacarpal, and readily distinguishable by these circumstances. The carpal surface, by which it joins the unciforme, is triangu- lar and slightly convex; its radial edge touches the magnum. Continuous with this edge are two small faces, slightly convex, which join the contiguous faces of the third metacarpal bone. On the reversed side of the fourth metacarpal is an oblong face which joins the carpal end of the fifth metacarpal bone. In re- gard to its body and phalangial extremity, this bone resembles the two preceding, and therefore does not require a particular description. Of the Fifth Metacarpal Bone.—It is placed upon the un- ciforme exterior to the last, and is both smaller and shorter than the fourth. The carpal extremity presents a cy lindroid and slight- ly convex face, for articulating with the unciforme, at the radial margin of which is an oblong facet, for joining the fourth metacar- pal: just below the ulnar margin is a small tuberosity, into which is inserted the tendon of the extensor ulnaris. The lower or pha- langial extremit)', like that of the others, presents a convex ar- ticular face, extended in front for the flexion of the first phalanx. The body also corresponds with that of the others, excepting that it is more flat in front. Of the Phalanges. The fingers are named numerically, beginning at the fore fin- ger; they are also named from their functions, as Indicator, Im- pudicus, Annularis and Auricularis. Each finger has three bones in it, called its phalanges: the bone adjoining the metacarpus is the first phalanx, the middle bone is the second, and the other the third. The first phalanx is the largest. Its posterior face is semi- cylindrical, the anterior face is flattened, and concave in its length. The two surfaces run into each other by forming a ridge on either side, from which arises the theca of the flexor tendons. The metacarpal extremity is enlarged, and presents a superficial cavity, which receives the end of the metacarpal bone. On either side of this end of the bone is a small tuber THE HAND. 199 for the lateral ligament. The lower extremity is also enlarged and flattened at its sides. Its articular face is extended in front, and presents two condyles, or small heads, for joining the se- cond phalanx. The second phalanx is likewise second in size and length. It is semi-cylindrical on its posterior face, flattened on its ante- rior, which is somewhat concave in its length, and the two sur- faces form a ridge, on either side, into which the tendon of the flexor sublimis is inserted, and from which arises the theca of the flexor tendons. Its extremities are slightly enlarged: the articular face of the upper presents two superficial cavities for the condyles of the first phalanx; the articular face of the lower extremity presents a trochlea, with a slight elevation at each side. The third phalanx is the smallest of the three, and is very different from the others. Its superior extremity being en- larged, presents an articular face, having two superficial cavities, which adjust themselves to the corresponding face of the last described bone. The inferior extremity is semicircular, thin, and flattened, its margin being very rough, and somewhat ex- panded. The posterior face of the body is convex, and the an- terior flat. The phalanges of the middle finger (Impudicus) are larger and longer than the others. The phalanges of the fore finger (Indi- cator) are next in size, but not in length, as the ring finger is rather longer than it. The phalanges of the ring finger (Annu- laris) are next in size, and those of the little finger (Jluricula- ris) the smallest and shortest of any. The thumb (Pollex) having but two phalanges, the first cor- responds sufficiently in its general form with the first one of the fingers; it may be distinguished, however, by its shortness and additional size. The second phalanx of the thumb, correspond- ing with the third of the fingers, is only to be distinguished by its additional bulk and length. All the metacarpal and phalangial bones have condensed la- mellated structure externally, and a cancellated one internally: 200 SKELETON. and, like other bones, are more compact in their bodies than at their extremities. There are two small hemispherical bones, called sesamoid, placed upon the trochlea, at the lower extremity of the meta- carpal bone of the thumb. They answer the purposes of patel- lae, and facilitate the action of the short flexor muscle. The metacarpal bones of some of the fingers are, in robust indivi- duals, occasionally furnished in the same way. SECT. V.--OF THE DEVELOPMENT OF THE UPPER EXTREMITIES. At birth the upper extremities are larger in proportion to the lower than they are at any subsequent period of life, owing, perhaps, to the umbilical arteries, which carry off to the placenta of the mother the greater part of the blood which afterwards goes to the lower extremities. The nearer a foetus may be to the embryo state, the more marked is this relative size of the extremities, which becomes gradually less obvious till the age of puberty, when it almost entirely disappears. At birth, the ends of the clavicle are, in consequence of their advanced ossification, much less cartilaginous than those of the other cylindrical bones. Its shape, also, approaches nearly to that of the adult state. The scapula is also in an advanced stage of ossification, and large. The glenoid cavity, though still cartilaginous, is well sustained by a bony basement coming from the central point of ossification of the scapula, and is much farther ossified than the acetabulum. The acromion, the coracoid process, and the an- gles, are still cartilaginous. The os humeri is cartilaginous at both extremities, which are also larger, proportionally, in consequence of this state. Its inferior extremity is remarkable for the size of that portion of it which articulates with the radius. In the fore arm the extremities of its bones are cartilaginous. The ulna has the olecranon large, while its coronoid process is comparatively small; the greater sigmoid cavity is, consequent- ly, not so concave as in the adult. The position of the radius, at its upper end, is somewhat peculiar, for it is much more an- terior than in the adult; a circumstance depending upon the MECHANISM OF THE UPPER EXTREMITIES. 201 greater size of the little head of the humerus, upon which it rests. This arrangement renders pronation more extended in the foetus, as the radius always crosses the ulna with additional facility, by being placed more anterior to it. This fact is strong- ly exemplified in the bones of a fore extremity of animals. Bi- chat observes, that this greater extent of pronation exposes the annular ligament to being stretched considerably behind, and, consequently, the radius to. luxations at its head; an accident by no means unfrequent among children. Dr. Physick says, that he has often seen it in consequence of nurses incautiously seizing them by the fore arm to help them over gutters, or to render them other assistance. It happens while the arm is in a state of pronation; for the weight of the body, by hanging from it, increases, the position distends the ligaments, and pro- duces luxation. ^As the bones of the fore arm in the foetus are nearly straight, the interosseal space decreases gradually from above downwards. The carpus is entirely cartilaginous at birth, and consists in the same number of pieces that it does in the adult. Its arti- cular cavities are well formed. Its size is proportionate to what it is in the adult: in this respect it differs from the cartilaginous extremities of the round bones, which are always larger from being in this state. The carpus, therefore, appears small in the foetus. The metacarpus is cartilaginous at its extremities, but ossified in the middle. The phalanges are in the same state. SECT. VI.--OF THE MECHANISM OF THE UPPER EXTREMITIES. The scapula and clavicle are for the superior extremity what the os innominatum is for the inferior; in consequence of which, some anatomists consider them as a part of the trunk of the body. Though the convenience of anatomical description ge- nerally requires them to be associated with the upper extremi- ty, I shall depart from the rule on the "present occasion, and view them only as the basis of the attachments and motions of the os humeri, and of the remaining parts of the superior ex- tremity. Vol. I.—26 202 SKELETON. The upper extremities, considering them as commencing with the ossa humeri, differ materially in their position from the lower. They are placed much farther behind; of which one may be satisfied fully by drawing a line from the middle of the glenoid cavity, to the middle of the acetabulum of the same side; the body being perfectly erect at the time, the line will be found oblique. The advantage of this arrangement is to give greater latitude of motion to the upper extremity than if it had been placed more in front. Another important benefit is, that by the bulk of the shoulder being placed behind the centre of gravity, the erect position is more easily preserved; a different position of it, by throwing its weight forwards, would have had a continual tendency to produce falls, and to effect somewhat, in man, the same inconvenience which is felt by the quadruped in the erect position. Another point, also of some interest in the position of the upper extremities, is the distance to which they are separated from each other by the lateral pro- jection of the scapulae, and, consequently, of the glenoid cavi- ties. A distance owing to the length of the clavicles, and which considerably exceeds the distance between the heads of the ossa femorum. When the whole length of the superior is compared with that of the inferior extremities, the difference is not so great as one may suppose. The former is ascertained by a line drawn from the head of the os humeri to the end of the middle finger: as the hand is parallel with the bones of the fore arm, its length is also included, which amounts to a considerable portion of the whole. On the contrary, from the foot being articulated at right angles with the leg, only its thickness contributes to the length of the lower extremity. As far, however, as individual bones are con- cerned, those of the upper extremity, with the exception of its phalanges, are uniformly shorter than the corresponding bones of the lower extremity. The os humeri is much shorter than the os femoris—the bones of the fore arm than the bones of the leg—the carpal and metacarpal bones than the tarsal and meta- tarsal. , The bones of the upper extremity are much less robust than those of the lower, a very certain indication of the difference of the uses for which they were intended. Their articular surfaces MOTIONS OF THE SHOULDER JOINTS. 203 are arranged for great variety and extent of motion, in the seizing and handling of bodies; whereas in the lower extremity, they are fashioned so as to suit the comparatively limited num- ber of motions requisite to progression, and to sustain the body firmly in the upright position. The carpus and metacarpus are much smaller than the tarsus and the metatarsus, because the latter are intended to support a great weight. On the contrary, the phalanges of the fingers are much better developed than the phalanges of the toes, because the latter are not destined to hold bodies and to examine them, and may be dispensed with both in standing and in progression. The motions of the upper extremity are immensely varied, and by a short attention to them some useful hints may be ob- tained in regard to dislocations. SECT. VII.--OF THE MOTIONS OF THE SHOULDER. The clavicle performs a very important office in the actions of the shoulder, by preserving it in a fit attitude for the motions of the upper extremity. The simple movements of the clavicle, of which the sterno-clavicular articulation is the centre, are those of elevation, depression, advancing, and retreating, and a rapid succession of these produces circumduction. The weight of the shoulder is also sustained by the clavicle, by the latter being fastened at the extremity next to the sternum, and having in the cartilage of the first rib a fulcrum, intermediate to this attach- ment and to the weight at its other end. This is proved con- clusively by its fracture; for in that case the shoulder inva- riably falls down, from the lever being broken which kept it up. The clavicle, also, by keeping the glenoid cavity at a dis- tance from the side of the thorax, and directed outwards, gives great facility and latitude to certain motions in the human sub- ject; and which are performed with difficulty, and very imper- fectly, in animals not having a clavicle. A principal one of these motions is circumduction, manifested by the elbow being turned inwards or outwards, and in most persons extends to three-fourths or even an entire circle. This motion concurs in the action wrhich brings the hand to the mouth, in consequence 204 SKELETON. of which such an action is performed with difficulty when the clavicle is broken. After an accident of the kind, the head, in- stead of remaining stationary as usual, is advanced towards the hand, without which the act cannot be accomplished. A certain length in the clavicle seems indispensable to the vigorous and perfect action of the shoulder in particular movements; if the clavicle be disproportionately long, as in females, these move- ments are executed with inevitable awkwardness and imbecility; as, for example, in throwing a stone. The scapula presents a moveable basis, on which the motions of the arm are accomplished. Its primary motions are such as have been assigned to the clavicle, in consequence of the con- nexion between these bones; besides which, in all the extreme motions of the humerus, backwards or forwards, the scapula is caused to perform a partial rotation, the axis of which is indi- cated by a line drawn from the end of the acromion to the in- ferior angle. When the arm is brought very far forwards, the inferior angle of the scapula is carried outwards, and somewhat elevated, while the superior angle is directed towards the spine, and somewhat depressed. But, when the arm is carried very far backwards, the inferior angle is directed towards the spine, and the superior angle looks forwards and upwards. The cla- vicle in these cases moves inconsiderably, as the scapula enjoys a pendulous motion, and its point of suspension is the outer end of the clavicle; at which place the oblong articular surfaces slide laterally upon each other and decussate. The extreme de- grees of these motions tend to dislocate this articulation, but the accident is prevented by the strong coraco-clavicular ligament, which, by its peculiar position and conformation, resists firmly at a certain point In the abduction and adduction of the arm the scapula is motionless. SECT. VIII.--OF THE MOTIONS OF THE SHOULDER JOINT. The os humeri is susceptible of elevation, depression, ad- vancing, retreating, circumduction, and rotation. In elevation, the head of the os humeri slides downwards in the glenoid cavity, and distends the lower part of the capsular MOTIONS OF THE SHOULDER JOINTS. 205 ligament. In this motion the scapula is apt to follow it; in which case there will be a less degree of distention on the cap- sular ligament. If the os humeri be carried forwards, its ele- vation is performed with much more ease, from the readiness with which the scapula follows it; but if it be carried backwards, this facility is much diminished. It is in the latter position, therefore, that dislocations downwards are most disposed to oc- cur when violence is offered to the joint. If in every case the scapula could follow the motions of the os humeri, so as to pre- sent fairly its glenoid cavity, luxations would be comparatively rare; but generally the violence offered transmits its momentum so speedily to the joint, that the muscles of the scapula are taken by surprise, and have not time to adjust properly the glenoid cavity. In the depression of the os humeri, the parts constituting the shoulder joint are in their most natural and easy position. The capsular ligament becomes very loose below, and is somewhat stretched above. Any degree of force which might be applied to the member, is warded off and its direction changed by the intervention of the trunk of the body. Should, however, the force be applied directly in the axis of the bone, the projection of the acromion process, and the strength of the triangular liga- ment of the scapula, would arrest the dislocation. When the os humeri is advanced, the posterior part of the capsular ligament is put upon the stretch; but the form and ar- rangement of the articular surfaces are somewhat favourable to this position, and accordingly it is one of but little inconve- nience. When the os humeri is retracted, its head, by being directed forwards, exercises considerable force upon the fore part of the capsular ligament, and when assisted by an external momentum is disposed to dislocation, forwards and inwards. The motion of circumduction is very extensive in the shoul- der joint; and by it the os humeri describes a cone, of which the glenoid cavity is the apex. It is a regular succession of the movements already mentioned, and in consequence of all the motions forwards of the os humeri being more easy and natural, the axis of the cone, instead ofbeing directly outwards, is some- what forwards. By rotation, is meant the revolving of the os humeri upon 206 SKELETON. itself. The centre of this movement is not the axis of the bone, but is removed to one side of it, by the lateral projection of the head. The neck, however, is too short and thick to permit any great extent to this motion; it, accordingly, is limited in such a way as never to amount to luxation. Its greatest extent, in most persons, does not exceed the describing of half a circle, which may be ascertained by applying a finger upon the internal con- dyle of the humerus. By it the capsular ligament is rendered, alternately, loose and tense on its front and back parts. Bichat observes, that in the anchylosis of the elbow joint, this motion, by habit, is much augmented, so as to supply the want of rota- tion of the head of the radius upon the ulna. The scapula and the clavicle do not vary their position in rotation. SECT. IX.--OF THE MOTIONS OF THE FORE ARM. There are two kinds of motion in the fore arm. In the one, the fore arm is flexed, or extended upon the arm, and in the other, the radius only changes its position in regard to the ulna. 1. The ulna is the essential agent of the first, in consequence of its manner of articulation with the os humeri; the radius is only accessory, and is drawn by the ulna into a participation in its motions. These two bones, it will be recollected, are dis- posed of in an inverse manner, the larger part of the ulna being above, while the larger part of the radius is below. This ar- rangement causes the ulna to present the principal articular sur- face for union with the os humeri, while the radius affords the principal surface to the carpus; it also gives to the whole fore arm a great uniformity in its transverse diameter. The fore arm executes, upon the arm, flexion, extension, and lateral in- clination. Where the flexion is complete, the coronoid process is re- ceived into its cavity, on the front of the humerus; and the ole- cranon, having left its cavity, is placed below the condyles. In this state the capsular ligament is stretched at its posterior part, while the' anterior is thrown into folds, and is relaxed along with the lateral ligaments. In the demi-flexion of the arm, there is a more equal degree of tension of the several ligaments. MOTIONS OF THE SHOULDER JOINTS. 207 When the os humeri is reposing in its most easy attitude, at the side of the body, if the fore arm be flexed, its line of motion directs the hand towards the mouth; a circumstance which is accounted for by the peculiar obliquity of the trochlea, on the lower part of the os humeri, upon which the ulna revolves, and is independent of any special act of volition. It is said that man, above all other animals, has the mechanism of the upper extremity most particularly addressed to the latter motion, to the perfection of which the clavicle is indispensable. It is in consequence of this application of the clavicle, that if it be broken, man, like animals which are entirely deprived of it, will, in the flexions of the fore arm, more easily carry the hand to the opposite shoulder than to the mouth. In the full extension of the fore arm, the olecranon process being received into its cavity, is much above the condyles of the os humeri. The lateral ligaments, as well as that part of the capsule on the front of the joint, are in a state of tension. When the extremity is in this position, a fall upon the hand may produce a dislocation backwards. In this case, the fore arm being fixed, the coronoid process affords the surface upon which the principal momentum of the fall is felt. If the liga- ments on the front of the joint be not strong enough to with- stand the force, they are lacerated, and the articular surfaces, passing each other, the upper parts of the ulna and radius are driven behind the os humeri. Bichat asserts, that nothing is more easy than to produce such a luxation on the dead body by a similar proceeding, and that he has repeatedly done it—that it is about as easy to produce this dislocation, as it is difficult to effect one at the scapulo-humeral articulation. In a moderate extension of the fore arm, produced by a small weight suspend- ed on the hand at arm's length, there is a well marked pressure of the inferior extremity of the humerus against the ligaments in front of the articulation, which is augmented by a tendency of the ulna to describe the arc of a circle, from above down- wards, and to separate itself from the humerus. In this case, the muscles which flex the fore arm are kept so much in the line in which they contract, or are so little removed from the axis of their own motion, that they contribute but little to sus- tain the fore arm in situ; the weight is, therefore, actually sus- 208 SKELETON. tained by the ligaments in front of the articulation. But they being pressed and drawn in the manner mentioned, such great pain and weariness are produced as to render a continued sus- pension of the weight insupportable, the experimenter is, there- fore, in a short time, under the necessity either of casting off the weight or of giving such a degree of flexion to the fore arm as will allow the muscles to contract more advantageously. Besides flexion and extension, the ulna has a sort of rocking motion when the fore arm is only half bent; but when the lat- v ter is at either extreme of the former positions, this motion is imperceptible, owing to the nature of the articular surfaces and the resistance of the ligaments. 2. In the rotations of the radius upon the ulna, the latter is almost motionless, excepting the case specified in the last para- graph. The position of the radius on a plane somewhat ante- rior to the ulna, its small cylindrical upper extremity, and its broad lower one, all concur in facilitating rotations forwards and backwards. It is owing to the hand following these mo- tions that the first is expressed by the term pronation, in which the palm of the hand is directed downwards; and the second, supination, in, which the palm is upwards and the back of the hand downwards. Pronation is the most common, and, consequently, the easiest position to the fore arm, when not carried to an extreme: it is adopted involuntarily, simply by the action of the ligaments and the particular shape of the articulating surfaces of the bones. It is the posture most generally suited to the examination and grasping of surrounding bodies. In order that it may be ac- complished fully, the superior extremity of the radius rolls on its own axis, in the loop formed by the annular ligament and the lesser sigmoid cavity of the ulna; while the lower extremi- ty revolves around the little head of the ulna below. The mid- dle part of the radius crosses that of the ulna, and the interos- seous space is diminished. An excess of this motion will pro- duce luxation either above or below, but more easily at the latter place; both on account of the greater extent of motion there, and of the comparative weakness of the ligaments. In supination, a movement the reverse of what is described, MOTIONS OF THE HAND. 209 takes place; the radius revolves outwardly, and is brought pa- rallel with the ulna. If by any force it be carried beyond this line, a dislocation may occur, in which the little head of the ulna, abandoning the sigmoid cavity of the radius, will be thrown in front of it. An accident, however, said to be very unusual. Bichat considers the cartilage between the ulna and the cu- neiforme as a principal obstacle to these luxations; but when it is insulated or separated from the cartilage of the radius, as some- times occurs, the joint is very much weakened thereby, and more exposed to dislocations. SECT. X.--OF THE MOTIONS OF THE HAND. The hand, as a whole, performs upon the fore arm, flexion, extension, lateral inclination, and circumduction. As it only follows the motion of the radius in pronation and supination, and does not contribute in the slightest degree to either, its ap- propriate motions can all be performed independently of them. In flexion, the convex head, formed by the first range of car- pal bones, slides from before backwards in the concavity which receives it. The posterior part of the capsular ligament is stretched, and the anterior thrown into folds, while the lateral ligaments remain at their ease. In extension, with the excep- tion of the lateral ligaments, the phenomena are reversed. This extension, as is well known, not only brings the hand into the same line with the bones of the fore arm, but carries it beyond that line till it forms almost a right angle with it. The wrist joint, in this respect, differs from the other ginglymous articu- lations; but what it gains in extension it loses in flexion, as it cannot be bent so much as either the elbow or knee.t The ar- rangement, however, gives great facility to the use of the hand. In the lateral inclinations of the hand, the capsule in front of and behind the wrist, is but little affected, but the lateral liga- ments are alternately relaxed and tightened. As the articular surfaces are extensive in the line of these motions, dislocations in the direction of either of them are very uncommon, and when they do occur they are for the most part incomplete. Vol. 1—27 210 SKELETON. Circumduction is produced by a regular succession of the motions described: it, therefore, does not require a specific no- tice. Of the Partial Motions of the Hand.—Well marked changes of position occur between the first and second rows of the carpus: these are principally flexion and extension. Late- ral inclination or abduction and adduction are extremely limit- ed, and circumduction does not exist. The motions, such as they are, are confined within much narrower limits than those of the radio-carpal articulation, and have for their main fulcrum the head of the magnum. The lateral articular surfaces of the several bones of the car- pus, though they present the arrangement of joints, have not an appreciable motion upon each other. Whatever changes of po- sition happen among them, are probably so obscure that they never appear, except under the influence of great and sudden violence. The complexity of the mechanism of the w7rist, seems to have a double object in view; for ordinary circum- stances of impulse and motion, the'flexion and extension of the first row uponf the second, as a whole, is sufficient; but when a great momentum is communicated to the structure, the number of pieces which form it, and the variety of their shapes and mode of attachment, diffuse the violence throughout the whole wrist, and generally save it from dislocation or fracture. The fracture of a single bone, excepting from gun-shot wounds, is a very un- usual circumstance: I have, however, in possession a scaphoides which was broken through transversely, and had probably been in that state for a long time; as all appearance of inflammation, at the period of my finding it, was absent, and as the fractured surface had become highly polished by rubbing against one an- other. The pisiform bone moves with much freedom inwardly and outwardly on the cuneiform, but its motion up and down is re- sisted by the muscles which are attached to it. Owing to its ar- ticular cavity being insulated, and to its own remoteness, a dis- location of it, if it did occur, would interfere but little with the general uses of the hand. MOTIONS OF THE HAND. 211 The metacarpal bone of the thumb has a very free motion on the trapezium, in flexion, extension, adduction, abduction: and circumduction is the result of the other four. In consequence of this variety of movement in it, of its position on a plane an- terior to that of the fingers, and of a corresponding obliquity of the trapezium, the thumb can, in all cases of grasping and examining bodies, antagonize the fingers. The circumduction of the thumb resembles very much that of the wrist, or shoul- der joint, though the mechanism of the articular surfaces is dif- ferent. In this motion, it describes a cone or circle, the ante- rior segment of which is larger, and performed with more fa- cility than the posterior. The second and third metacarpal bones are so closely bound to the carpus, that their motion above is almost imperceptible; in consequence of their length, the motion is more appreciable below, but even there it is very much restricted. The fourth metacarpal bone has a limited ginglymous movement, which is sufficiently demonstrable, and the fifth has it in a considerable degree; it also admits of a sort of adduction, by which it is brought nearer to the other bone. The first phalanges admit of flexion, extension, adduction, ab- duction; and circumduction, by the successive performance of the others. The first phalanx of the thumb has the three last motions very much curtailed, in consequence of the necessity of great strength and stability in this joint, so as to antagonize firmly the fingers. The remaining phalanges perform, simply, flexion and extension. The latter, as in the knee and elbow, rarely goes beyond the axis of the limb, whereas the former, from the extent of the articular surfaces and the particular me- chanism of the joint, permits the hand to be closed and dou- bled. From what has been said, it will not be difficult to form a general conception of the great variety of motions resulting from the number and arrangement of the pieces constituting the upper extremity. The os humeri being the basis of them, may be presented in any direction; the bones of the fore arm 212 SKELETON. may be alternately retracted or ejected, and by the revolving of the radius, will permit the palm of the hand to apply itself at any point; and, again, the multiplicity of simple motions of the hand, and the exhaustless variety of their compounds, contri- bute to give to the upper extremity, in man, a perfection of me- chanism infinitely beyond any thing which can be devised by the powers of art: a sentiment cogently expressed by the late Professor Wistar; who remarked, that " The human hand, di- rected by the human mind, is the most perfect instrument that man ever saw or ever will see." CHAPTER VI. OF THE INFERIOR EXTREMITIES. The bones of the inferior extremities are, the os femoris, the tibia, fibula, patella, and a large number which enter into the composition of the foot. sect. i.—of the thigh bone, (Os Femoris, Femur.) This is the only bone in the thigh, and extends from the trunk to the leg. It is considerably the longest and largest bone in the skeleton, and presents a conformation entirely peculiar. For the purposes of description, it is divided into the two extremities and the body. The superior or iliac extremity presents three well marked eminences, the head, the great and the little trochanter. The head is the articular surface above, and forms rather more than one-half of a perfect sphere. Its smoothness indicates the exist- ence of a cartilaginous crust on it during life, and is only inter- rupted by a small pit a little below its centre, which gives at- tachment to the round ligament of the hip joint. Its articular surface is more extensive above than below, as that part is chief- ly employed in sustaining the trunk, and comes in contact with a corresponding surface of the os innominatum. The head is sup- thigh bone. 213 ported on a branch of the os femoris called the neck, which, pro- jecting from the internal face of the bone between the trochanters, is directed inwards and upwards at an angle of about thirty-five degrees, but varying in different subjects. The neck is two inches in length, oval, or resembling a flattened cylinder, the greater diameter of which is vertical; and arises by an extensive base along the upper end of the os femoris. It has a great mul- titude of foramina dispersed over it, which penetrate to its interior, and give passage to blood vessels; the largest of them are on its posterior surface. Some of these foramina are also occupied by fibres. A superficial horizontal fossa, formed by the tendon of the obturator externus, may be seen crossing the posterior face of the base of the neck. The great trochanter is situated at the superior part of the base of the neck, and though presenting a well marked, elevated summit, rising straight upwards, does not reach the altitude of the head, but falls short of it half an inch. The trochanter major rests upon a broad base, has its surface much diversified, is somewhat prominent in front and externally; but presents on the side which is next to the head of the bone a deep rough con- cavity, which is occupied by the insertion of the small rotatory muscles on the back of the pelvis. On its summit is a small smooth spot, marked by the insertion of the pyriformis muscle; below this, and also externally, is a broad surface, slightly con- vex, into which the gluteus medius is inserted; below this, again, is a second prominent and rounded surface, over which a part of the tendon of the gluteus maximus plays. On the front of the trochanter, and just in advance of the insertion of the gluteus medius, is an oblong surface, proceeding obliquely downwards and outwards, into which is inserted the gluteus minimus. The trochanter minor is much smaller than the other, and is a conical process, placed on the internal posterior face of the bone, at the lower end of the root of the neck. It receives the common tendon of the iliacus internus and psoas magnus mus- cles. A broad elevated ridge joins the two trochanters on the posterior face of the bone, and from its middle half arises the quadratus femoris muscle. A much smaller ridge, and by no 214 SKELETON. means so elevated, runs in front, from the one process to the other, and indicates the line of attachment of the capsular liga- ment of the hip joint. The inferior extremity of the os femoris is much more volu- minous than the superior, and is divided into two parts, called the internal and the external condyle. These condyles are of very nearly the same size, but, being separated by a notch behind, they are/placed somewhat obliquely in regard to each other; and the internal, from being the most oblique, and, consequently, the most protuberant, also seems to be the larger. If the os fe- moris be placed exactly vertically, the internal condyle has the appearance of being the longest; but, if it be placed in its natural obliquity, the lower face of the condyles is on the same plane. In front, the condyles unite to form an articular pulley, on which the patella plays: this pulley is unequally divided by a vertical depression, so as to have its more extensive surface ex- ternally. This latter surface is the anterior part of the external condyle, and is much more elevated than the internal part of the trochlea, which belongs to the internal condyle. Posteriorly, the internal condyle projects more than the external, and both have the articular surfaces, there, so much elongated backwards and upwards, as to admit of a very great flexion of the leg. Each condyle presents an internal and an external face. The internal condyle has on its internal face a tuberosity, from which proceeds the internal lateral ligament of the knee; on its external face it forms one-half of the notch which separates it from the other condyle, and at its anterior part in the notch may be ob- served a small depression, from which proceeds the posterior cru- cial ligament. The external condyle, also, has on its external face a tuberosity, from which proceeds the external lateral liga- ment of the knee, and just below it a depression for the origin of the popliteus muscle. Its internal face forms the other half of the notch just mentioned, and on the posterior part of this face is a small depression for the attachment of the anteror crucial liga- ment. The inferior face of the condyles is somewhat flattened, the transverse diameter of that of the external being rather longer than the other. The inferior extremity of the os femoris thigh bone. 215 is beset with foramina, large and small, for the passage of vessels and the attachment of fibres. The body of the os femoris begins at the trochanters, and ter- minates in the condyles. It is slightly bent, so as to present the convexity of the curve forwards. Its size is gradually diminished to the middle; it then begins to enlarge, and continues to aug- ment till it terminates in the large inferior extremity. The body is very nearly round, and departs from that figure only on its posterior face, where an elevated rough ridge is found, occupying the superior two-thirds of the bone, and called the linea aspera. The linea aspera begins broad, rough, and flat, on a level with the trochanter minor; it narrows as it descends, and becomes, at the same time, more elevated. Its lowe? extremity bifurcates into two superficial, slightly marked ridges, one on each side, which may be traced into the posterior extremity of its corre- sponding condyle. Between these ridges the surface of the bone is flattened. In the whole course of the linea aspera, an internal and an external margin is very obvious. The superior half of the latter is occupied by the insertion of the gluteus maximus, and the remainder by the origin of the biceps flexor cruris. This margin also gives origin to the vastus externus. The inter- nal margin of the linea aspera is generally occupied by the in- sertion of the triceps adductor, and by the origin of the vastus internus. In the linea aspera, near the middle of the bone, is the canal for the nutritious artery, which slants upwards: occasionally one or more canals, besides, are found in it for the same purpose. The texture of the os femoris is compact in its body. Its ex- tremities are cellular, with the exception of a thin lamina form- ing their periphery, and the cylindrical cavity in its middle, like that in all the other long bones, is reticulated. The ossa femoris approach each other very closely at their inferior extremities, but are widely separated at their superior, in consequence of the length of their necks, and of the distance of the acetabula from one another. 216 SKELETON. SECT. II.--OF THE LEG. Two bones form the leg, the tibia and the fibula, to which may be added the patella, from its attachment to the tibia. Of the Tibia, (Tibia.) The tibia is placed at the internal side of the leg, and extends from the thigh to the foot. After the os femoris, it is the longest and the largest bone in the skeleton. It is divided into the body and the two extremities. The superior extremity of the tibia is oval, tranversely, and presents an extent of surface suited to the articular face of the two condyles of the os femoris, to which it is joined. It has here two superficial cavities for receiving the ends of the condyles; one of them is internal and the other external. The internal is the deeper and more extensive of the two, and, being oval, has its long diameter in an antero-posterior direction. The external, besides being smaller and more superficial, is more circular; and, from the want of elevation in its margins, scarcely presents at all the appearance of a cavity. These two cavities, which approach to within half an inch of each other, are kept entirely separated by an elevated triangular ridge, with a broad base, called the spinous process of the tibia. The summit of the ridge presents two tubercles, one at each end, separated by a pit,~which serves to attach the posterior end of the external semi-lunar cartilage. The ridge is placed nearer the posterior than the anterior mar- gin of the tibia. Its base, in front, is depressed by the attachment of the anterior crucial ligament, and just before this is a rough, triangular space, extending to the anterior margin of the bone, and covered by fat in the recent subject. Between the ridge and the posterior margin of the bone is a deep depression for the attach- ment of the. posterior crucial ligament. The circumference of the superior part of the tibia, just below its articular surface, is flat before, somewhat flat and concave behind, and bulging at the sides. The flatness, in front, is THE LEG. 217 triangular, having its base upwards and the apex downwards, the latter terminates in a well marked, broad, rough rising, which is the tubercle of the tibia, and serves for the insertion of the tendon of the patella. The concavity behind is made by the popliteus muscle, and slopes from above obliquely inwards and downwards. The projection is great on the internal side of the upper extremity of the tibia, and at its posterior part has a depres- sion made by the insertion of the semi-membranosus tendon. The external projection is thicker in front than behind; at the latter point it has a small articular face, looking downwards, for the head of the fibula. The inferior extremity of the tibia is much smaller than the superior. It is terminated by a transverse quadrilateral cylin- drical concavity, by which it articulates with the astragalus. This concavity is narrower and deeper internally than external- ly, and is traversed from before backwards by a low broad ridge. It is bounded internally by the internal malleolus, a large pro- cess of half an inch in length, the external side of which is a con- tinuous surface with the cylindrical concavity, and forms part of the joint. The other side of the malleolus is superficial, being just beneath the skin. A shallow groove exists in its posterior part, which transmits the tendons of the tibialis posticus and of the flex- or longus digitorum pedis. Inferiorly, the malleolus is notched, or presents a depression, for the origin of the internal lateral ligament, and just before the depression it is elongated into a point. The lower end of the tibia presents, before and behind, a slight swell, running transversely just above the articular surface. The pos- terior swell is occasionally slightly marked by the tendon of the flexor longus pollicis. Externally, the circumference of the lower end of the tibia presents, longitudinally, a concavity which is in contact with the lower end of the fibula. This concavity terminates, insensibly, above, but is deep below, where it is bounded before and behind by an elevated point of bone, of which the posterior is the high- est. The concavity is placed nearly in the vertical line of the little articular face for the fibula, on the head of the tibia; and at its lower margin, there is frequently a small lunated surface, Vol. I.—28 218 SKELETON. which is continuous with the articular surface, for the astragalus, and is consequently a part of the cavity of the ankle joint. Just above this lunated surface the bone is rough for the origin of short ligamentous fibres, which unite it to the fibula. The body of the tibia commences just below the enlarged up- per extremity, and terminates near the ankle. In the front view of it, it diminishes continually in descending, in its superior two- thirds ; afterwards it enlarges gradually to the lower extremity; in the lateral view it diminishes downwards almost to the lower extremity. It is slightly bent forwards, and is generally prisma- tic, more particularly above: one of its faces is internal, another external, and the third posterior. The internal face is rounded, and, with the exception of its upper part, where the flexor ten- dons are inserted, it is only covered by the skin. Its external face is flat, excepting below, where it is rounded and is covered by the muscles on the front of the leg. The posterior face is slightly rounded, except at its upper part where it is crossed by a line running obliquely from the articular surface for the fibula, downwards and inwards: above which line, is the superficial tri- angular depression for the popliteus muscle. The three sides of the tibia are marked off from each other by ridges of bone. The anterior ridge, called the spine or crest, be- gins at the external margin of the tuberosity for the insertion of the tendon of the patella, and may be traced very distinctly, in the form of an S very slightly curved, almost to the ankle; it is more elevated in its middle. The external ridge is a straight line running from one extremity of the bone to the other; to it is attached one edge of the interosseous ligament. The internal ridge is rounded, but also runs the whole length of the body of the bone, being more distinct below. The internal lateral liga- ment of the knee and the soleus muscle are attached to it, above; and below, the flexor longus digitorum pedis. Foramina large and small, for blood vessels and fibres, are found on the circumference of both extremities of the tibia. On its posterior face, about one-fourth of its length from the head, is a large canal sloping downwards, through which passes the nu- tritious artery. Its structure, like that of the other long bones, THE LEG. 219 is cellular at its extremities; but compact in the body, and pre- sents a cavity occupied by cancellated matter. It will now be understood how it articulates with the fibula, externally, at both ends, with the os femoris above, and with the astragalus below. Of the Fibula, (Perone.) The fibula is placed at the external side of the tibia, and ex- tends from the head of the latter to the foot: it is much smaller, and not quite so long as the tibia, and is so articulated with it as to be on a line with its posterior face. It is to be studied in its two extremities and in its body. The upper extremity of the fibula is considerably enlarged and irregular. It presents, above, a small articular face directed upwards and very slightly concave, by which it joins the corre- sponding face of the tibia. This surface is bounded behind by a sort of styloid process, into which is inserted the tendon of the biceps flexor cruris. The circumference of the bone, in advance of this, furnishes attachment to the external lateral ligament of the knee. The inferior extremity of the fibula is also enlarged, being flattened on its tibial side, but more rounded externally. This part of the fibula is called the malleolus externus. It descends lower than the internal ankle, and is also more prominent and large. Its tibial side presents, below, a small triangular slightly convex articulating surface, which reposes against the side of the astragalus; behind, and somewhat below it, is a small rough depression, which, with the adjoining inferior margin of the bone, gives origin to the three fasciculi of the external lateral ligament of the ankle. Above the articular surface, the bone is rough and slightly rounded where it is received into the side of the tibia, and sends off many short ligamentous fibres to it. The anterior margin of this extremity of the fibula is thin and pro- jecting, the posterior surface is flat and broad, and is slightly scooped out into a longitudinal groove, which transmits the ten- dons of the two peronei muscles. The pointed termination 220 SKELETON. below, of the malleolus externus, is sometimes called the coro- noid process. The body of the fibula extends between its extremities. It is irregularly triangular, somewhat smaller above than below, thick posteriorly, thin anteriorly, and slightly convex in its length behind. There are three faces to the fibula, one is external, another in- ternal, and the third posterior. The first is semi-spiral, and turned forwards above; its superior third gives origin to the pe- roneus longus muscle, and the middle third to the peroneus se- cundus: its lower third exhibits the semi-spiral arrangement which may be traced into the groove on the posterior part of the malleolus externus, and thereby indicates the course of the ten- dons of the peronei muscles. The internal face is directed to- wards the tibia; it is divided by a low longitudinal ridge into two parts, of which the anterior is the more narrow. The ridge itself, well marked in the middle two-fourths of the bone, is in- distinct above and below; and furnishes attachment to the inter- osseous ligament. The space in front gives origin to the extensor proprius pollicis, and the extensor communis digitorum: and the space behind gives origin to the tibialis posticus. The posterior face is also somewhat semi-spiral, its superior end being out- wards, and the inferior end inwards. The superior third gives origin to the soleus muscle, and the remainder to the flexor lon- gus pollicis. The angles of the fibula which are formed by the junction of the three surfaces described, differ somewhat among themselves. The anterior angle is frequently very sharp and elevated in its middle half, and below it bifurcates into two ridges, including between them a triangular space, which is only covered by the integuments. The posterior angle is well marked, and winds so as to be external above, and posterior near the foot. The in- ternal angle, formed by the union of the internal and the poste- rior surfaces, is only very well marked in its middle half. The projection of this angle gives to the bone the appearance of in- THE LEG. 221 clining inwards towards the tibia, besides which it has actually a little bend in that direction. Near the middle of the posterior face of the fibula, a canal, sloping downwards, conducts the nutritious artery. The circum- ference of the extremities, like that of the other long bones, pre- sents a multitude of foramina for the vessels and filaments of fibres to pass. It is composed in its extremities of cellular or spongy structure, and in its body of compact matter, enclosing a cavity occupied by cancellated structure. Of the Patella (Rotule.) The patella is a small bone, intermediate to the thigh and to the leg, and placed on the fore part of the knee joint; it is smaller in proportion in females than in males. Its anterior face is uniformly convex and rough, and is studded with a considerable number of .foramina for the passage of ves- sels, and for the attachment of fibres. The course of the longi- tudinal fibres composing the front of the bone, is also well marked. The posterior face of the patella is an extensive articular surface, divided unequally by a broad longitudinal elevation, which runs from the superior to the inferior margin of the bone. The part of this surface external to the ridge, is the largest and the most concave, and is applied to the trochlea, in front of the external condyle of the os femoris; while the smaller surface is on the in- ternal side of the ridge, and is applied to the trochlea of the in- ternal condyle. The circumference of the patella is nearly oval, the long di- ameter being transverse. Its thickness is much augmented above, where it presents a rough, and somewhat unequal flatness for the insertion of the tendon of the rectus femoris. Below, the bone is thinner, and elongated into a conical point, from which proceeds the tendon of the patella to be inserted into the tibia. Laterally, the margins are thinner still. The texture of the patella is cellular, covered by a lamina of condensed bony matter. It is developed in the tendon of the ex- 222 SKELETON. tensors of the thigh, and with the exception of its posterior face remains in a state almost entirely cartilaginous, for a year or two after birth. Its base is, therefore, fibrous, in which is de- posited, subsequently, the calcarious matter. In its fractures union is effected more frequently by the fibrous base alone, than by perfect ossification. In order to put it into its proper position, turn the point downwards, and apply the greater surface behind, to the trochlea of the external condyle. The patella is said to be to the tibia, what the olecranon is to the ulna; and is, there- fore, a sort of appendage to it, united by ligament instead of being continuous with it, as is the case with the olecranon. SECT. III.—OF THE FOOT. The foot forms the third section of the inferior extremity, and is placed at right angles to the bones of the leg. The size of its bones varies much in different individuals, depending much upon their modes of life, and dress: it also varies much in the two sexes, being, for the most part, smaller in the female. The foot is oblong, narrower behind than before; presents one surface above, which is its back, and another below, which is the sole; a posterior extremity called the heel, and an anterior extremity called the point; also its internal margin is much thicker, longer, and more concave, than the external margin. The foot is divided into Tarsus, Metatarsus, and Toes or Phalanges. Of the Tarsus, (Tarse.) The tarsus forms the posterior half of the foot, and is com- posed of seven distinct bones, which are arranged on a plan, and present features, having scarcely a single point of resemblance with the carpus. These bones are, the Os Calcis, the Astraga- lus, the Naviculare, the Cuboides, the Cuneiforme Externum, Cuneiforme Medium, and Cuneiforme Internum. OF THE FOOT. 223 Of the Os Calcis, (Calcaneum.) The calcaneum, or heel bone, forms, almost exclusively, the posterior half of the tarsus, and may be readily distinguished by its greater magnitude. Its shape is very irregular. Its greatest diameter is longitudinal; it is also thicker vertically than transversely. The superior face is deeply scooped out, at its fore part, and is formed there into two articular surfaces, for joining with the astragalus: these faces are separated from each other by a rough fossa, which runs obliquely forwards and outwards. The ante- rior external part of the fossa is deep, broad, and triangular; the posterior part is narrow, is occupied by a ligament, and allows the two articular surfaces to come nearer. Just behind the fossa is the first articulating surface, lying parallel with it; being ob- long, convex, semi-cylindrical, and looking obliquely upwards and forwards. Before the fossa is the second surface: it is ob- long, much smaller than the first, and is very frequently divided into two by a transverse notch, and is concave. The part of the bone upon which this face is wrought, is called, by the French, the little apophysis. I have frequently remarked, that the face posterior to the first mentioned fossa is smaller and more vertical in the African than in the European; the os cal- cis, behind it, is also smaller and longer. The upper posterior face of the bone is somewhat concave. The under surface of the os calcis is slightly concave, longi- tudinally. It is bounded, behind, by two tuberosities, of which the internal is larger than the external; they both give origin to the muscles of the sole of the foot and to the aponeurosis plan- taris. There is also a tuberosity bounding the same surface in front, from which arise the ligaments that connect this bone with the adjoining ones. The anterior extremity of the os calcis forms the greater apo- 224 SKELETON. physis, and is terminated in front by a triangular and slightly concave surface, by which it articulates with the os cuboides. The posterior extremity is convex and rough: into the lower part of it is inserted the tendo-achillis; the upper part is sloping and more smooth, in order to accommodate this tendon in the flexions of the foot The external surface of the os calcis is flat, with the excep- tion of a gentle rising in its middle; it is marked, occasionally, by a superficial groove, indicating the course of the peronei muscles. The internal surface is very concave, and obtains the name of sinuosity; along it pass the tendons of several muscles from the back of the leg, of which that of the flexor longus pol- licis makes a conspicuous groove on the under surface of the little apophysis. Of the Astragalus, (V Astragale.) This is the next in size to the os calcis, and is placed on the superior part of the latter, between it and the bones of the leg. The astragalus presents, above, a semi-cylindrical surface, by which it is put in contact with the tibia. This surface is nar- rower, and continued farther behind than it is before; is slightly depressed, longitudinally, in its middle, and, consequently, pre- sents an elevated margin on either side, of which the external is the broadest and highest. This articular face continues on each side of the bone, and is more extensive externally, where it comes in contact with the fibula or malleolus externus, than internally, where it touches the malleolus internus. The inferior face of the astragalus is traversed by an oblique rough fossa, going from within Outwards and forwards, and cor- responding in size with that on the upper face of the os calcis. Behind the fossa, and parallel to it, is a deep oblique semi-cylin- drical concavity, suited to the adjoining face of the os calcis; and before the fossa is a narrow oblong convexity, suited to the corre- THE FOOT. 225 sponding articular concavity of the same bone. When the latter is divided into two facets, the concavity of the astragalus presents also two facets, separated by a small ridge. The anterior extremity of this bone is terminated by a convex head, the horizontal diameter of which is the greatest. This head articulates with the scaphoides, and is continuous with the surface that rests upon the little apophysis of the os calcis. On the internal side of the head is a small triangular surface, conti- nuous with the others, that rests upon a strong ligament going from the os calcis to the scaphoides. Above, immediately before the surface for the tibia, is a small depression, which, in the flex- ions of the foot, receives the anterior margin of the articular sur- face of that bone. The posterior extremity of the astragalus is thin, and has a notch, or groove, formed in it by the tendon of the flexor longus pollicis. Of the JVaviculare, or Scaphoides, (Scaphoide.) It is situated at the internal side of the tarsus, between the astragalus and the cuneiform bones, and has its greatest diameter transverse. Its circumference is oval, broader above than below, and at its internal side presents a large tuberosity; into which is inserted the tendon of the tibialis posticus. Sometimes the ex- ternal margin has a small articular face, where it comes in con- tact with the cuboides. The scaphoides presents, behind, a deep concavity, which re- ceives the head of the astragalus; anteriorly, it is somewhat con- vex, but this surface is divided by small ridges into three trian- gular faces, for the three cuneiform bones. Of these faces the internal is broader below than above; the others are broader above than below. Of the Cuboides, (Cuboide.) It is situated at the external side of the tarsus, between the os calcis and the metatarsal bones. Its figure is irregular; but, per- Vol. I.—29 226 SKELETON. haps, sufficiently indicated by its name. It is narrower exter- nally than internally, and has the posterior extremity oblique. The superior face of the cuboides is rounded, but rough. The inferior face has in its middle a broad elevated ridge running al- most transversely, but somewhat forwards. The external extre- mity of this ridge is marked by a trochlea, on which plays the tendon of the peroneus longus; the tendon is then conducted along a groove between the ridge and the anterior margin of the bone. The internal face is flat, and has in its middle a circular facet where it comes in contact with the cuneiform externum. The posterior face joins the os calcis, is triangular, and somewhat con- vex. The anterior face is oblong, transversely, and is divided by a slight vertical rising into two, for articulating with the two last metatarsal bones. Of the Cuneiforme Internum, (Premier Cuneiforme.) It is placed at the internal anterior extremity of the tarsus, be- tween the scaphoides and the first metatarsal bone, and may be distinguished from the other cuneiforms by its greater size. Its •thickest part is below. The anterior face presents a long vertical convexity, which joins the first metatarsal bone. The posterior face is not so ex- tensive, and is formed into a triangular concavity, having the broadest part below, which joins the internal facet of the sca- phoides. The internal side is semi-cylindrical and rough; it is marked, anteriorly, near its middle, by the tendon of the tibialis anticus. The external side is somewhat concave, and generally rough, and is marked just below its superior margin by two ar- ticular facets, of which the anterior is the smaller, and comes in contact with the second metatarsal bone; the posterior, from.its concave obliquity, gives a slope to the upper margin of the bone, and is in contact with the cuneiforme medium. THE FOOT. 227 Of the Cuneiforme Medium, (Second Cuneiforme.) The middle or second cuneiform bone is placed upon the sca- phoides, immediately on the outside of the cuneiforme internum. It may be distinguished by being the smallest bone of the tarsus. Its figure resembles sufficiently well a wedge; the base of which is above, and the edge below. Its posterior face is slightly concave where it joins the sca- phoides ; the anterior face is slightly convex, and articulates with the second metatarsal bone. The internal face presents, superi- orly, an oblong, slightly convex, and oblique articular facet, which touches the cuneiforme internum: what remains of this side is rough, for the origin of ligamentous fibres. The external face is somewhat concave, and presents, at its posterior part, a vertical articular face for joining the cuneiforme externum ; but anteriorly, it is rough for the origin of ligamentous fibres. In the articulated foot the lower part of this bone is almost concealed between the other two cuneiforms. Of the Cuneiforme Externum, (Trbisieme Cuneiforme.) The external or third cuneiform bone is placed upon the sca- phoides, between the second cuneiform and the cuboides. Of the three bones it is the second in size, and is also appropriately named from its shape. The base is upwards. The posterior face furnishes, on its superior half to join the scaphoides, a quadrangular articular facet, sloping outwardly, below which the bone projects into the sole of the foot. The an- terior face is flat, and articulates with the third metatarsal bone. The internal face presents, above, two articular facets, of which the one at the posterior corner is larger than the other, and joins the second cuneiform; the other, at the anterior corner, is very small, and touches the second metatarsal bone. Below these facets the bone is rough, and gives origin to ligamentous matter. The external face, at the middle of the base, forms an angular projection, behind which is a small oval articular surface that 228 SKELETON. joins the cuboides. The remainder of this face is rough, for the origin of the ligaments, with the exception of a very small arti- cular facet at the anterior superior corner, which joins the fourth metatarsal bone. The structure of the bones of the Tarsus is uniformly cellular within, the cells being enclosed by a thin lamella of condensed matter. The astragalus is rather stronger and more compact than any of the others. 1 have seen one instance, however, in which it had been separated into two pieces by a transverse ver- tical fracture, going from the ankle joint to the articulation with the os calcis. The observation was made after it had been boiled: the callus had completely united the two fragments, and no dis- placement had occurred. Of the Metatarsus, (Metatarse.) The metatarsus succeeds to the tarsus, and is formed by five long parallel bones. They are called numerically, beginning on the inner side, or that of the great toe. There are four intervals between them, which are filled up by the interosseous muscles. Of the First Metatarsal Bone. Placed at the inner side of the foot upon the cuneiforme in- ternum, and forming the base of the great toe, it may be readily distinguished in the separated bones by its greater size and short- ness. The posterior extremity presents an oblong articular concavity, the greatest length of which is vertical, for joining the cuneiforme internum. The internal semi-circumference of this extremity is convex, while the external is slightly concave or flat; below, it presents a prominent tubercle, into which is inserted the tendon of the peroneus longus. The anterior extremity, also called the head, is rounded and THE FOOT. 229 convex, forming an articular surface for the first phalanx of the great toe. This surface is continued far back below, and pre- sents there, for the sesamoid bones, a trochlea with a longitudinal ridge in its middle. The lateral surfaces of the head are rough and concave, for the origin of the lateral ligaments. The body is much smaller than the extremities, and is pris- matic. Its internal side is rounded, the external side flattened, and the inferior side concave,-longitudinally, for lodging the mus- cles of the great toe. Of the Second Metatarsal Bone. This is the longest of any, and may be distinguished from the others principally by that circumstance. The posterior extremity is triangular, the broadest part being above. It presents a surface very slightly concave, almost flat, which rests upon the cuneiforme medium. The circumference of this extremity being flattened, laterally, is locked in between the internal and external cuneiforms; on its internal side, above, is an articular facet, where it comes in contact with the cunei- forme internum, and, externally, it has two articular facets. The posterior one of the latter touches the cuneiforme externum, and the anterior, which is smaller, comes in contact with the third metatarsal bone. These two facets run into each other by an angular rising. The anterior extremity is convex and rounded; its vertical diameter is more considerable than its transverse, and the arti- cular face which it furnishes to the second toe is continued con- siderably below, in order to assist the flexion of the first phalanx. Its circumferences is rough, and flattened, laterally, for the origin of the capsular ligament. The body is smaller than either of the extremities, and de- creases gradually from behind forwards. It is flattened on each side, and elevated, longitudinally, above and below, into a ridge. 230 SKELETON. There is a curvature in its length, which makes it convex above, and concave below, for the lodgement of muscles. Of the Third Metatarsal Bone. This is rather shorter than the second, but has very much the same shape. Its posterior extremity, or base, is triangular, has the broadest part above, and articulates with the third cuneiform ; the surface for the latter, slopes outwardly. Its circumference is flattened, laterally, and presents, internally, at its superior corner, a small face, which articulates with the second metatarsal; externally, it also presents, at its superior corner, an articular facet, which joins the fourth metatarsal. Its body and anterior extremity, do not present any essential points of difference from the second metatarsal. Of the Fourth Metatarsal Bone. It is somewhat shorter than the third, and is placed upon the internal of the two anterior faces of the cuboides. The posterior extremity, or base, is more quadrangular than the base of the preceding bones. It presents an articular face to the cuboides, which is also square, or nearly so, flat, and slopes outwardly. On its sides it is irregular; internally, at the superior margin, it has two articular facets, continuous with each other, but forming thereby an obtuse angle; the anterior joins the third metatarsal; and the posterior, which is much the smaller, touches the cuneiforme externum. Below these, the surface is rough. The articulation with the cuneiforme externum is occasionally deficient. I have observed the latter, particularly in the negro, and it seems to arise from the unusual development of the cu- boides. The external surface of the base has at its superior cor- ner an articular facet for the fifth metatarsal bone, and below it an oblique deep fossa, before which is a tubercle. THE FOOT. 231 The anterior extremity and the body of this bone, though smaller than those of the preceding, do not present any essential points of difference. Of the Fifth Metatarsal Bone. This is shorter than any of the others, excepting the first, and is placed on the front of the cuboides, externally. Its base is remarkable, and distinguishes it strongly, by being projected considerably beyond the external margin of the cuboides, and forming there a large tubercle, into the superidr part of which is inserted the tendon of the peroneus tertius, and into the posterior part, the tendon of the peroneus secundus. The base, also, has a triangular flat surface, sloping considerably outwards, which articulates with the cuboides. On the internal side is the articular facet, whereby it joins the base of the fourth metatarsal bone. The base is flattened below, rough, and somewhat convex above. The anterior extremity is more rounded than that of the other metatarsal bones, but in other respects similar. The body is prismatic; being flat below, flat internally, and slightly rounded externally. Of the Toes. The toes are five in number, and named, numerically, by be- ginning at the great one. They each are formed by three bones called the phalanges, with the exception of the great toe, which has but two of them. The phalanges are distinguished into first, second, and third. In these several respects the toes correspond with the fingers. Of the First, or Great Toe. The first phalanx of the great toe is longer and much larger than any other. Its base is large, and forms a deep concavity for receiving the end of the metatarsal hope. Its anterior ex- 232 SKELETON. tremity is formed into two small condyles, for being received into the second phalanx. This bone is broad, and strong, being semi- cylindrical above, and flat below. The second phalanx corresponds in its appearance with the third of the other toes, but is much larger than any of them. Its base is broad and flat, and has two superficial cavities for the condyles of the first phalanx. The anterior extremity is expanded semicircularly, and converted into a very scabrous surface, for the firmer attachment of the soft parts about it. The body of this phalanx is constricted in the middle, rounded above, and flat be- low. Connected with the great toe, are two small hemispherical bones, lying upon the trochlea of its metatarsal bone, and im- bedded in the tendons of the small muscles which move the first phalanx. They are the sesamoids, and present, superiorly, an articular surface, covered with cartilage, which enters into the composition of the joint; and below, a rounded surface, which has nothing remarkable. The sesamoid bones, though generally appropriated solely to this joint, are yet frequently found elsewhere. For example, in the second joint of the same toe—in the first joint of the other toes—in the articulation of the first phalanx of the thumb, with its metacarpal bone—in the first joint of the fingers—in the knee joint, behind each condyle—and, in advanced life, in tendons where they slide upon bone§. Ancient luxations give a disposi- tion to their development in the capsular ligaments of the gin- glymous joints, of which a very interesting specimen may be seen in the Anatomical Museum, occasioned by an external lateral dislocation of the elbow. Of the Small Toes. Their phalanges bear a general resemblance with those of the fingers, but are neither so large nor so long. The first phalanges are successively diminished to that of the DEVELOPMENT OF THE INFERIOR EXTREMITIES. 233 little toe, and are almost precisely like each other. Their pos- terior extremities, or bases, form a cavity deeper in proportion than in the fingers, for receiving the ends of the metatarsal bones. The anterior extremities are fashioned into two small condyles for forming a hinge-like joint with the second phalanges. The bodies are smaller than the extremities, more rounded and nar- rower than in the fingers'. The second phalanges are very short, the extremities being so near each other that the body is of inconsiderable length, parti- cularly as regards the two last, where it forms a mere line of se- paration. The posterior end has two superficial cavities for re- ceiving the first phalanx, the anterior end is imperfectly fashioned into two little condyles for joining the third phalanx. The third phalanges have a well-formed articular surface for joining the second. The anterior extremity is rough, for the at- tachment of the adjoining soft structure. This phalanx of the fourth and fifth toe is frequently very imperfectly developed, be- ing a mere tubercle with an articular face at one end. The structure of the metatarsal and phalangial bones resem- bles that of other long bones. Porous and cellular at the extre- mities, their bodies are composed of compact lamellated matter, enclosing a cancellated texture. SECT. IV.--OF THE DEVELOPMENT OF THE INFERIOR EXTREMITIES. The comparatively small quantity of blood which is sent to the ■ lower extremities of the foetus, is the cause of their not being so large in proportion to the upper, at the time of birth, as they are subsequently. Our wants immediately after birth, and during the first months of life, are naturally such as to require but little service from the lower extremities, in which is seen a striking correspondence between the internal arrangements of the animal economy and its actual necessities; or, in other words, a conti- nued and rigid adaptation of means to produce a certain effect. The os femoris at birth presents several peculiarities^ The su- Vol. L—30 234 SKELETON. perior extremity being in a cartilaginous state, is placed more at a right angle to the body of the bone than it is in the adult. The neck is short, which by diminishing the base of support to the trunk, makes the progression of infants more tottering and infirm. The lower extremity is also cartilaginous and large. The body of the bone has but a very slight degree of curvature, which like- wise increases the difficulty of standing and walking in very young subjects. The patella is cartilaginous. In the leg the bodies of the tibia and fibula are ossified, but their extremities are cartilaginous. The bones of the tarsus, with the exception of parts of the os calcis and of the astragalus are cartilaginous. The metatarsus and the phalanges are ossi- fied in their middle, but cartilaginous at their extremities: their development is not so complete as that of the corresponding bones of the hand. About the fifteenth year, the bones of the lower extremities have very nearly the same forms as in the adult: they are all fully ossified, with the exception of their extremities not being fused or joined to their bodies; but still in the state of epiphyses, and, therefore, separable either by boiling or long continued macera- tion. Exclusively of this condition, which sometimes remains to the twentieth or twenty-fifth year, the epiphyses are as fully os- sified as at any subsequent period of life. SECT. V.--ON THE MECHANISM OF THE INFERIOR EXTREMITIES IN REGARD TO STANDING. The os femoris is well adapted by its shape and position to the erect attitude. The curvature which its bftdy makes in front has the effect of advancing the lower part of it, and there- by keeping it in a line with the centre of the trunk; but if it had been perfectly straight, the erect position would have been main- tained with great difficulty, owing to the centre of the trunk being in advance of this bone. Under the latter circumstances, an incessant tendency to fall forwards would have manifested itself, which could have been obviated only by flexing the ossa femorum very much at the hip joint, or by keeping one foot al- ways in front of the other. Even under the actual arrangement MECHANISM OF THE INFERIOR EXTREMITIES. 235 of the skeleton, when muscular support is withdrawn from it sud- denly, it falls forwards, owing to the weight of the parts anterior to the spine being greater than that of the parts posterior to it. When muscular action is weakened or badly regulated, the same tendency to fall forwards is manifested: children continually tumble in that direction: a person in a state of intoxication, somewhat •short of the entire loss of locomotion, not being able to sustain the trunk of the body erect by the muscles of the back*, inclines forwards, and would be precipitated to the ground, were it not that at this crisis one leg is involuntarily advanced, so that the base of support is much augmented. But if the in- dividual attempt to walk, the continued necessity of keeping a large basis of support to prevent the body from falling forwards, urges him into a slow running or trotting gait. The arrangement of the whole upper extremity of the os fe- moris is also highly favourable to the erect attitude and to loco- motion. The neck of the bone, by its length and oblique posi- tion in regard to its body, enlarges transversely the base of its support, and gives great stability in preventing the trunk from falling either to the right or left; while it contributes at the same time to the facility of progression, in permitting the os femoris to bend forwards and backwards. The lateral or transverse extent of the base, thus obtained, cannot be supplied with equal effect in any other way, as a certain proportion between the diameters of the pelvis and the length of the neck of the thigh bone is in- dispensable. In females, where the transverse diameter of the pelvis is greater than in males, though standing is equally secure as in the latter, yet their progression is always marked by a waxit of firmness strongly characteristic of the sex. The strength of articular connexion of the os femoris with the innominatum is confirmed by the acetabulum being placed where the latter is re-enforced by the linea ilio pectinea, and by the anterior infe- rior spinous process; and as the principal weight of the trunk is sustained by the acetabulum, immediately below the latter pro- cess-, we accordingly find it at this point of the greatest depth. It is also to be stated, that the capsular ligament at this part is stronger than elsewhere, thereby conforming strictly to the gene- ral purposes of the articular connexion. The capsular ligament 236 SKELETON. is assisted by the ligamentum teres, which by arising from the lower margin of the acetabulum and passing upwards to the head of the os femoris, prevents the head from sliding upwards, while it permits it to swing freely backwards and forwards in its socket. In erection, the bones of the leg are in a line with the vertical diameter of the trunk: in this respect they differ very materially from the os femoris, which not only inclines forwards in its de- scent, but also leans towards its fellow internally, and almost touches it at the knee. This relative position of the leg and thigh is obtained by the greater length of the internal condyle of the os femoris, and also by the other peculiarities of form in the latter; whereas the tibia is nearly straight in the direction of its long diameter, and has a horizontal articular surface above, whereby it and the os femoris make an entering angle externally, and a salient one internally. Under common circumstances, the weight of the trunk is transmitted to the foot exclusively through the tibia, owing to the fibula not entering into the composition of the knee joint, and not being sustained by any bony basement at its inferior part. The fibula is principally intended for the ori- gin of muscles, and for the lateral security of the ankle joint; and may be broken without the accident suspending either erection or locomotion. The position and shape of the foot concur largely in the gene- ral object of maintaining the human being in the erect attitude. Fixed at right angles to the leg, and articulated by a surface in the centre of its most solid structure, the tarsus, it receives the weight of the body perpendicularly upon the astragalus. The latter being the key-stone to the arch, diffuses the pressure through the remainder of the structure, so that the whole foot is planted against the ground, an attitude more fully executed by man than by any other animal. The tendency of the body to fall forwards, requires a very considerable elongation of the foot in front of the tarsus, in order to increase the extent of the base of support in that direction.' We accordingly find the metatarsal bones not only forming bases for the flexion of the phalanges; but also, by their great length, by the flatness of the articular faces MECHANISM OF THE INFERIOR EXTREMITIES. 237 which they present to the tarsus, and by their consequent im- mobility at these points, extending and securing the base of the body in that direction to which its gravitation most inclines it. The first metatarsal bone, though corresponding in place with the first metacarpal, is very unlike it in other respects. Of predominating magnitude, but parallel with the other bones, and immoveable at its base, it is obviously intended for sustaining the body, and least of all for prehension and for antagonizing the other bones, as is the case with the thumb. The points on which the foot is particularly pressed when we stand, are the tuberosity of the os calcis, the tuber of the base of the last metatarsal bone, with the under surface of the cuboi- des, and the anterior extremity of the first metatarsal bone. The arch of the foot, upon which this depends, may be considered in two ways: one is in the longitudinal direction, and has its abut- ments in the os calcis behind, and in the ends of the metatarsal bones in front; the other is transverse, is but slightly elevated externally, indeed almost flat, while it is raised to a considerable height internally. This double arrangement is eminently service- able in many respects: it permits a concavity in which the mus- cles of the toes may repose and act without being pressed upon by the superincumbent weight of the body—it also permits a free flow of blood and of nervous energy to this structure, gives a very elastic base to the whole body, and allows itself to be applied to such inequalities of surface as it meets with. It has been agitated, by some ingenious inquirers into the ori- ginal condition of man, whether the erect attitude is natural to him and not the result of an advancement in civilization. In- dependently of the proofs derived from the authentic reports of travellers concerning the varieties of the human family, from none of whom have we reason to believe that the latter have any where been found adopting habitually the attitude of quad- rupeds ; there are evidences derived from the general mechanism of the skeleton, still more conclusive, that standing is fully na- tural to us. For example, 1st, The position of the foramen mag- num occipitis, evidently farther forwards in man than in animals, indicates that his voluminous head is to be kept in equilibrium 238 SKELETON. by a vertical line of support near the centre of its base. 2d. The ligamentum nuchae, weak in man, is strong in quadrupeds. 3d. The curvatures of the spine are so varied as to diminish the ten- dency to fall forward when we are erect. 4th. The direction of the orbits of the eyes, which looking forwards, when we stand, and enabling the eye to apply itself to a vast circumference, would, in the quadruped position, be directed towards the ground, and thereby have the sphere of observation reduced to, a few yards. 5th. The opening of the nostrils, when we stand, permits odours to ascend easily into the nose; in the other attitude this opening would be directed backwards. Such are the circum- stances, in connexion with the head only, which indicate the ne- cessity of the biped position for the full enjoyment of the func- tions which the Creator has given to us. But there are, also, others equally evident in the mechanism of the extremities, and of the parts of the trunk to which they are attached. Thus, 1st, The breadth of the pelvis, and the slight obliquity of its su- perior strait, in regard to the spine, prevents us from falling to one side, and, at the same time, brings the lower extremities im- mediately in a line with the spine. 2d. The length of the neck of the os femoris, and the size of its condyles. 3d. The articula- tion of the knee, which permits the leg to be brought into a line with the os femoris, a position impracticable in quadrupeds. 4th. The foot being articulated at right angles with the leg, and having its tarsus and metatarsus so well developed. 5th. The predominance of the transverse diameter of the thorax over the vertical, which, with the great length of the clavicle, and the shape of the scapula, unfit the latter for assisting much in pro- gression. 6th. The shape of the hand, calculated to seize upon objects, but from the length of its phalanges not suited to sustain the body. 7th. The mode of articulation at the wrist, which, from its mobility and weakness in the direction to which the weight of the body would be applied to it, could not be brought to support it advantageously. And, lastly, the great dispropor- tion of length, in the adult, between the upper and lower ex- tremities, when an attempt is made to walk like the quadruped. In considering the skeleton of the very young child, it is worthy of remark how closely its mechanism, with the exception of the MECHANISM OF THE INFERIOR EXTREMITIES. 239 head, corresponds with the habits of early life. A spine, nearly straight, and a pelvis, the lateral diameter of whose cavity is so small that the transverse base of support is much diminished, render erection inconvenient. Lower extremities shorter in pro- portion than the upper ones, having thigh bones nearly straight; also, the articulations of the knee not admitting of a full exten- sion of the leg. All these circumstances prove that the quad- ruped position, inconvenient and intolerably irksome when con- tinued for a length of time in the adult, is natural to the young infant. The space between the ossa femorum, produced by the breadth of the pelvis and the length of their necks, and, therefore, always considerable above, varies below in different individuals. A cer- tain distance at the latter point, seems to be indispensable to con- venient and graceful progression. Thus, when it is in excess, it produces the deformity called bandy legs, and causes a tottering gait, such as may be mimicked, at any time, by walking with the legs in a state of abduction: but, when diminished, it is called knocked knees, and interferes with the firmness of the step by causing the centre of gravity to pass, alternately, through the in ternal condyles of the ossa femorum, instead of falling exactly be- tween them. The firmest position in which we can stand is that in which the feet are perfectly straight and parallel with each other, so as to form a square base for the support of the trunk. If from this position the toes be turned either inwards or outwards, the con- sequent reduction of the antero-posterior diameter of the base,. causes less resistance to the natural inclination of the trunk for- wards. Whatever may be the grace and the ultimate intention of the first position in dancing, to wit, that of having the feet nearly in the same line, with the heels touching and the toes outwards, it is certainly the most unfavourable attitude for ease in keeping the body erect that can be adopted ; for the base of support being diminished, both by the length of the body of the os calcis, and by that of the foot, anterior to the ankle joint, the trunk is con- tinually inclining either forwards or backwards, and is prevented 240 SKELETON. from falling only by the alternate action of the muscles behind and in front. When we are upon the knees, the base of support for the trunk being entirely withdrawn in front, it is necessary, in order to maintain the position, and to prevent failing forwards, that the hip joint be flexed so as to throw the weight of the body en- tirely behind the thigh bones. The position is one of so much restraint and fatigue upon the muscles, that it can be maintained for a long time, only by some artificial support in front, or by the buttocks falling down upon the legs, and resting against them. The position we assume on being seated in a chair, is the easiest of any of those in which the trunk is kept erect, or nearly so. The.length of the lever, represented by the whole length of the skeleton, is then diminished one-half; consequently, any pre- ponderance of it at particular points, above, bears with less force upon the base. The base itself is much augmented by the ampli- tude of the buttocks, and by the horizontal position of the thigh bones in front; and may be also increased, at pleasure, by the extension of the legs. If, under such circumstances, the trunk of the body be slightly advanced, its equilibrium is so easily main- tained as to require but a very little muscular action to continue * it. The most exposed part of the base is backwards; and, if the trunk be kept perfectly erect, there is some tendency of it to fall into that direction. Hence, the utility of backs to seats, and the fatigue from such as have not. SECT. VI.—ON THE MECHANISM OF THE INFERIOR EXTREMITIES IN REGARD TO LOCOMOTION. 1. Of the Motions of the Thigh. These, like the motions of the os humeri, upon the scapula, consist in extension, flexion, abduction, adduction, rotation, and circumduction; but, in consequence of being performed upon an immoveable basis, the acetabulum, they are much less extensive. MECHANISM OF THE INFERIOR EXTREMITIES. 241 In order that they may be understood well, it will be useful to assume certain points of reference in the os innominatum and femoris. These are the trochanter major, the pubes, and the anterior superior spinous process of the ilium. In standing, the lower external part of the trochanter major, where it forms a bulge on the side of the thigh bone, is on a horizontal line with the upper part of the symphysis pubis. A triangle, described by lines drawn from the anterior superior spinous process to the sym- physis pubis—from the latter to the point mentioned of the tro- chanter, and from the latter to the anterior superior spinous pro- cess, will be nearly a rectangle, of which the base is above, and the shortest side behind. The flexion of the os femoris is that motion in which its lower extremity is carried forwards. It is performed with great ease and freedom, in consequence of the arrangement of the articular surfaces of the bones, and of the capsular ligament. The head revolves freely in the acetabulum, the ligamentum teres is put into a slight tension, and the end of the trochanter major ap- proaches the sciatic notch. The extreme point of this motion, is the one preserved by the os femoris of the foetus utero. Extension is the reverse of flexion. When the latter has been performed, extension restores the thigh bone to its vertical posi- tion, and carries it some degrees farther, but cannot be executed to the same extent behind, that flexion is in front. When pushed to an extreme, it brings the trochanter major under the inferior anterior spinous process of the ilium, and the round ligament is put very much upon the stretch; it is, finally, arrested by the lower part of the neck of the os femoris lodging against the pos- terior elevated margin of the acetabulum, and by the thickened part of the capsule, in front and above, being so much distended as not to yield farther without laceration. Abduction is the act by which the thigh bones are separated. When carried to an extreme, the under part of the head of the os femoris leaves the acetabulum, and distends very forcibly the capsular ligament at this point. The superior fasciculus of the round ligament is strongly extended; but the inferior fasciculus is kept easy, and, indeed, somewhat relaxed. This motion is ar- Vol. I.—31 242 SKELETON. rested by the trochanter major striking against the ilium; with- out which it would be much more extensive, as the capsular ligament is strained at its weakest point, and relaxed at the strongest. Adduction is the reverse of the last. The muscles which pro- duce it, the adductors, from their situation and course, are unable to give an extent to this motion much beyond the act of reinstating the thigh when it has been abducted. In this respect they are much less influential than the great pectoral muscle which adducts the os humeri. The articular surfaces of the bones are suited to a much greater latitude of this movement, but it is arrested both by a deficient power in the muscles, and by the strong upper part of the capsular ligament being put upon the stretch. Circumduction is the regular succession in a circle of the four preceding motions, and is much less extensive in the os femoris than in the os humeri, for the reasons stated. The centre of the circle, or cone, thus described, is the head of the bone, and it is much more extensive anteriorly and externally than posteriorly and internally. Rotation, owing to the length of the neck of the os femoris, is extremely well marked, and is indicated by the trochanter major moving backwards and forwards. The radius of the circle thus described, is the distance between the centre of the head of the os femoris and the bulging external part of the trochanter major. The rotation outwards or backwards is more fully and easily performed than the reverse, owing to the number and favourable position of the muscles causing it, many of which are specially appropriated to its production, and some others partially so. This movement is arrested by the neck of the bone striking against the acetabulum behind, and by the tension of the capsular liga- ment in front. Rotation, forwards, having but few muscles to produce it, and they neither specially devoted to it, nor acting very advantageously for the purpose, is arrested by the neck of the bone striking against the fore part of the acetabulum, by the tension, behind, of the capsular ligament, and, also, by that of the ligamentum teres. When the convexity and the neck of the os MECHANISM OF THE INFERIOR EXTREMITIES. 243 femoris look directly forwards, it is indicated by the great toe pointing in the same direction. 2. Of the Motions of the Leg. The movement of the leg upon the thigh is that of flexion, ex- tension, and a very partial degree of rotation. In flexion, the head of the tibia slides backwards upon the condyles of the os femoris, which are prolonged, behind, for the purpose of extending this motion. It is checked, when carried to an extreme, by the posterior margin of the tibia striking against the os femoris, and by the tension of the ligament of the patella. In the mean time, the lateral, the crucial, and the posterior li- gaments are relaxed. The patella, always stationary, and at the same relative distance in regard to the head of the tibia, slides downwards upon the trochlea of the os femoris, and in the flexed position sinks between the condyles, so as to come in contact with the ligamentum mucosum. In extension, the patella rises upon the condyles, and becomes prominent; the lateral ligaments are rendered somewhat tense, and the motion is, finally, checked by the resistance of the cru- cial and of the posterior ligaments of the articulation. The rotation of the bones of the leg can only be performed when they are flexed, and the ligaments, generally, thereby re- laxed, in which position a very limited motion, inwards and out- wards, is perceptible. The motion, outwards, is the more exten- sive of the two, in consequence of the arrangement of the crucial ligaments, which are separated from each other by it. The motion, inwards, is limited by these ligaments being brought im- mediately by it into close and resisting contact with each other. In either case, however, the posterior and the lateral ligaments all contribute, ultimately, to arrest the motion. In all these conditions of the leg, the semi-lunar cartilages slide somewhat upon the head of the tibia. The articulation between the tibia and the fibula is such as 244 SKELETON. to admit of no motion whatever below; but, above, a limited sliding backwards and forwards is performed by the fibula upon the tibia. This movement is made more perceptible in cases of extreme emaciation, and in general relaxation of the muscular system. 3. Of the Motions of the Foot. The general motions of the foot upon the bones of the leg are flexion, extension, and an inconsiderable inclination inwards and outwards. In flexion, the astragalus rolls backwards in the articular ca- vity formed by the tibia and the fibula, and is arrested by the anterior upper part of the astragalus coming in contact with the articular margin of the tibia. The ligamentous fibres and the synovial membrane, in front of the articulation, are relaxed;' those behind are in a state of tension, as well as the tendo-achil- lis, and the other tendons there. Luxation from an excess of this motion is impossible. In extension, the foot is brought with the point downwards, so as to have its upper surface almost on a line with the bones of the leg. The astragalus glides forwards; the tendons, on the back of the joint, are very much relaxed. The joint itself is in a state the reverse of the preceding. In the lateral motions, the sole of the foot is caused to present itself either obliquely inwards or outwards, whereby it may be accommodated to any inclined surface on which we walk. The first position is checked by the internal malleolus, and the ten- sion of the external lateral ligaments; the second, by the exter- nal malleolus, and by the tension of the internal lateral ligament. These motions constitute the adduction and the abduction of the foot; and by a regular succession with its flexion and extension, communicate a very limited and embarrassed species of circum- duction. « The bones of the tarsus, for the most part, have a 'very ob- scure motion upon each other, with the exception of the articu- MECHANISM OF THE INFERIOR EXTREMITIES. 245 lation between the astragalus and the scaphoides, and between the os calcis and cuboides. At these points the movement up- wards and downwards, makes a sort of flexion and extension of the fore part of the foot, which is very distinct. A species of twisting, or oblique gliding, is also slightly perceptible there. The bones of the metatarsus are susceptible of a slight eleva- tion and depression, which, almost imperceptible at their bases, become sufficiently obvious at their anterior extremities. They also may be slighly approximated, at their fore parts, by the ac- tion of muscles, and by external compression. When the weight of the body is thrown upon them, they separate from each other, and the metatarsus loses, in some degree, the arched form of its anterior extremity below. The phalanges of the toes have the same motions with those of the fingers, except that they are more restricted. The first ones, therefore, perform flexion, extension, adduction, abduction, and circumduction; the two last have only flexion and extension. The extension of the first phalanges is more extensive than their flexion, from whence results an important advantage in walking or in standing upon the toes. The shortness of the second and third phalanges of the small toes, together with the thickness of the sole of the foot contiguous to them in their extreme flexion, causes them rather to be doubled up on themselves, than on the sole of the foot. On the General Motions of the Lower Extremities. These may be resolved into three; walking, running, and leaping. In walking, though the first step may be taken in a variety of relative positions of the lower extremities to each other, yet it will make the investigation more clear to suppose the individual standing erect, with the two feet precisely on the same plane, and giving equal support to the trunk. The first step is then taken, by detaching the foot of one side from the ground; in order to do which, the thigh is bent upon the trunk, the leg 246 SKELETON. upon the thigh, and the limb by being thus elevated becomes shorter. At this period the ankle joint remains at rest, with a slight inclination of the toes downwards. By the subsequent re- laxation of the muscles of the limb advanced, with an inclination of the trunk to the same side, the limb is caused to descend upon the ground. These are the only motions when the step is short and easy; but, when a long stride is taken, by which the limb is put very much in advance of its fellow, in order to bring it to the ground, the pelvis is caused to rotate forwards on the head of the stationary thigh bone, whereby the trunk of the body, in- stead of presenting the sternum forwards, has it turned to one side. When a step has been taken so as to leave one inferior extre- mity advanced before the other, for example, the left, the limb behind is brought forward by the following mechanism: The left foot, remaining fixed, becomes the point of support to the trunk; and the right, which is behind, is elevated successively, from the heel to the toes, by the action of the muscles on the back of the leg, and rests upon the phalanges. The effect of this posi- tion is to elongate the right inferior extremity to the amount of the distance between the fore part of the ankle joint and the ante- rior extremity of the metatarsus, whereby that side of the pelvis is pushed forwards, and a rotation in advance impressed upon it. By the latter impulse, the foot of that side is wholly detached from the ground, the thigh being flexed at the same moment at the hip joint, and the leg flexed at the knee, the whole extremi- ty is carried forward and fixed upon the ground, after the man- ner described in the first step. Ordinary progression results, then, from the regular succession of the last motion in the two extremities. In regard to the impulsion of the pelvis from the foot behind, this will probably take place in every case, more or less; however, it maybe reduced very much by a certain extent of flexion at the knee joint; and the want of it not be felt, be- cause other powers concur to produce the same impulsion; as certain muscles, and also the momentum of swinging the lower extremity forward. An equality of length in the lower extremities is indispensable to graceful and regular progression. If one of them be short- ened from any cause whatever, it is manifested in the gait, by an MECHANISM OF THE INFERIOR EXTREMITIES. 247 unusual sinking of the pelvis on the defective side, at the mo- ment the foot is brought to the ground, and from the continuity of the pelvis with the upper parts of the body, a considerable lateral inclination is communicated to the latter in the same in- stant. The pains frequently taken to conceal this defect, dis- guise it very imperfectly, unless the shortness be only such as may be supplied by a shoe with a sole thicker than that of the other foot. Where the shortness arises from luxation upwards of the os femoris, a crutch, is the best substitute for sustaining that side of the pelvis. In running, the position of the feet is somewhat different from what it is in walking; they are extended so as to support the trunk on the phalanges alone, instead of on their soles: whereby a double advantage is obtained, that of keeping the lower extre- mities at their greatest possible length, and also of enabling them to detach themselves quickly from the ground. The velocity here is the principal difference between it and walking, yet there are some peculiarities. The trunk of the body is kept continually and largely inclined forwards, which enjoins the necessity of a quick successive ad- vance of the lower extremities to prevent it from falling. This position, also, by advancing the bony points, from which arise several of the muscles used in the extension of the thigh, removes these muscles more from the line of their contraction, and there- by enables them to act more advantageously and promptly. As each pace on these occasions is taken to the fullest stretch, the pelvis is rotated forwards from side to side, alternately, upon the head of the os femoris, which may be fixed at the time. The face being directed forwards, whatever rotation in the vertebrae can occur, is then performed. As the pelvis communicates its motions to the trunk, so the latter carries its own to the upper extremities; which are thereby slung, alternately, backwards and forwards, and are brought, continually, to adjust the centre of gravity, which is then more in danger of being lost than in ordinary walking. The ascent of an inclined plane, either by walking or running, is attended with unusual fatigue and difficulty, for the following reasons: In order to advance the thigh, it is necessary to give it 248 SKELETON. great flexion at the hip joint, the knee must also be bent in an equal degree, and the foot be flexed, in order to adjust it to the surface against which it reposes. To bring forward the other extremity, it requires an equal flexion at the hip and knee; be- sides which, its heel being below the phalanges, the foot must perform a full rotation at the ankle joint. The difficulty is somewhat diminished by stepping only on the phalanges. As, in these cases, the trunk of the body, to preserve its equilibrium, must be inclined forward, there are certain acclivities, which, though they furnish a base sufficiently large for the foot, are yet impracticable from not allowing the trunk to be thrown for- wards. The descent of an inclined plane is more easy, because it re- quires but little flexion, in the articulations mentioned, to bring the extremity behind on a line with that in front; and its subse- quent descent is produced by keeping it almost straight, and shortening the extremity which is fixed. Running is then at- tended with some inconveniences, for the impulsion, forwards, which this motion communicates to the trunk, assisted by the in- clination of the plane in that direction, determines a fall, inevita- bly, without a successively accelerated advance of the hind leg. We see frequently, in the descent of a very inclined hill, a step, at first guarded and leisurely taken, converted, unavoidably, into a full run, to prevent the body from being precipitated for- wards to the ground. In jumping, the whole body is projected abruptly from the ground, either in a vertical or oblique direction. In the first, the lower extremities are shortened by a general flexure of their articulations, and, by a very sudden and simul- taneous extension of them, the resistance of the ground causes the whole frame to mount upwards, till its gravitation causes the momentum to cease; it then descends on the same principle with projectiles, generally. In the oblique leap, there is the same flexion in all the articulations of the lower extremities, with the addition of an inclination, forwards, of the trunk. At the moment when the limbs straighten themselves, the trunk is projected, not only upwards, but forwards, owing to its inclina- tion, and describes in its ascent and descent a parabola. In this MECHANISM OF THE INFERIOR EXTREMITIES. 249 effort, the space traversed will be more considerable, if a pre- vious horizontal momentum has been communicated to the trunk by running several steps before the leap be made. The more oblique the leap is, the greater will be its extent, to effect which the trunk must be inclined proportionably for- wards. But, to obtain this inclination without falling, it is ne- cessary for one of the lower extremities to be very much ad- vanced at the moment of springing with the other, so as to con- vert the motion into a very long step. With this position of the lower extremities, a much longer space can be cleared than if they are kept together.* * For a farther exposition of the principles of locomotion, see Joh. Alph. Bo- relli de Motu Animalium, 1710. Haller, Element. Physiol, torn. iv. 1757. Bi- chat, Anat. Descript. 1801. Barthez, Nouvelle Mechanique des Movemens de l'Homme et des Animaux, 1798, Vol. I.—32 • BOOK I. PART III. CHAPTER I. ARTICULATIONS. OF THE CARTILAGINOUS STSTEM. Cartilages (Cartilagines, Systeme Cartilagineux,) sup- ply the place of bone in many parts of the human skeleton, as in the space between the ribs and sternum, in the larynx, in the external ear, in the nose, and elsewhere. They are also to be found in all the moveable, and in several of the immoveable ar- ticulations. Wherever placed they may be recognised by their whiteness, by their flexibility, by their great elasticity, and by a hardness only short of that of the bones. There are many animals whose skeletons are entirely cartilaginous, as the chon- dropterous or cartilaginous fishes, so excellent a substitute is cartilage for bone. Cartilages have neither canals nor cells in them. They appear homogeneous; and, upon a superficial inspection, present neither laminae nor fibres. The immersion of them in boiling water dissolves into a jelly, such as are found upon the articular sur- faces of the bones, and a few others; but, such as supply the place of bone, though softened by the process, are not rendered by any means so gelatinous. Their chemical analysis, accord- ing to Mr. I. Davy, is gelatine, 44.5; water, 55.; phosphate of lime, 0.5. The testimony of different experimenters, upon the latter point, does not coincide, and their results must vary ac- cording to the kind of cartilage, and the period of life. 252 SKELETON. Cartilages are composed of a tissue exclusively their own, and of parts which they have in common with other organs. The first has some very distinguishing properties. It resists putre- faction, either with or without maceration, longer than any other tissue, except the bones. In the midst of gangrene, it preserves its appearance almost unchanged. Boiling gives it a yellow co- lour, causes it to swell, and, if protracted, the gelatinous portion is dissolved. When dried, it becomes of a semi-transparent yellow, diminishes in bulk, and loses its elasticity; in these re- spects resembling ligaments and tendons. Cellular substance exists, in very small quantities, in carti- lage, and is, therefore, not readily demonstrated; it is, however, made manifest by maceration, and by the action of boiling wa- ter: the latter, by dissolving the gelatinous portion, leaves a membranous and cellular structure. It is also stated, that in certain diseases, the gelatinous portion being less abundantly secreted, the cellular is left in a soft, spongy condition. In a healthy state, no blood vessels can be seen in cartilages; yet there are the strongest proofs of a species of circulation going on in them, either by very fine capillary vessels, or an intersti- tial absorption. All experienced anatomists have seen, in sub- jects affected with jaundice, the entire cartilaginous system losing its brilliant whiteness, and becoming of a light yellow: also, the conversion into bone, in extreme old age, to which all cartilages, with but few, perhaps no exceptions, are subject; and this ossi- fication sometimes beginning in the centre of the cartilage, prove that the calcarious matter has been conveyed there by some kind of channel. Neither absorbents nor nerves have been traced into them, and it is not possible to prove, conclusively, their existence by the circumstances of disease. We only know, that in inflam- mations of the joints, terminating by anchylosis, the cartilages are absorbed; and that in some cases, even without evident in- flammation, the cartilage is removed from a joint as if it had been worn away. Ulcerations of the arytenoid cartilages are spoken of as common, by the French anatomists;* but it has not occurred to me to see either them or any others in this * I have, since the first edition of this work, seen one case. Am. Journ. Med. Sci. vol. i. CARTILAGINOUS SYSTEM. 253 state: Dr. Physick's experience is also the same with my own. Possessed of no animal sensibility in the natural state, it is doubtful whether they ever have it, or can inflame, as the pains in inflammations of the joints may arise from the synovial mem- branes. In the embryo, the osseous and cartilaginous systems are con- founded, so as to present a homogeneous, mucous or pulpy ap- pearance; they only become distinct by the deposite of calca- rious matter in the bones; when the latter are somewhat ad- vanced, the cartilages, which are to remain such, have also ad- ditional consistence, and more of a proper cartilaginous look; but the appearance is generally unsatisfactory, by which one can learn to distinguish the cartilages that are to remain such, from the cartilaginous rudiments of the bones. The following cir- cumstance, however, is pointed out by Bichat: in the cartilages of ossification, there is a vascular net-work between the carti- lage and the ossification which has occurred, and owing to the interposition of it, the two may be easily separated. But, in the permanent cartilage, this net-work does not exist between the proximate surfaces, consequently they adhere with a tena- city not admitting of a rigid separation from one another. As the individual reaches adult age, the cartilages acquire the strength, whiteness, and great elasticity which distinguish them. In old age they become yellowish, more brittle, and are, as said, generally disposed to ossify. Those of the ribs and larynx are frequently ossified at forty years of age. The ossification of those of the moveable joints is rare, and begins at a more ad- vanced period. In the two first it begins commonly near their centre, and in the last on the surface. ACCIDENTAL DEVELOPMENT OF CARTILAGES. The unnatural devolopment of cartilages, in the tissues and organs of the body, to which they are very slightly allied in their nature, is a circumstance by no means uncommon, and is met with annually, in most of its varieties, in our dissecting- rooms. As there is a great disposition in such cartilages to os- sify, they are presented in the.several gradations from a soft 254 SKELETON. gelatinous body to that of perfect bone. They occur in the ar- ticulations; in the lungs, and form there fistulous passages; very frequently on the surface of the spleen; in the pleura; in the fibrous coat of the large arteries, particularly the arch of the aorta; and in the semi-lunar valves of the same; in the ovari- um, when it becomes dropsical; and also in many other parts of the body. The cartilages which are found loose in the joints and float- ing about there, begin, for the most part, in the fibrous structure* exterior to the synovial membrane; the latter is protruded in- wards by them, and gives them a covering resembling the fin- ger of a glove. As these bodies are small and rounded, when they protrude into the joint the synovial membrane forms a pe- dicle or base to them, which is finally ruptured, and then the cartilage becomes loose. These bodies are generally ossified in their centre, of course they have gone through the usual pro- gress and phenomena of ossification. The other forms of pre- ternatural cartilage are much disposed to ossify in the arteries, but not so much so in the other organs. In these cases they are laminated and adhere by their surfaces, very closely, to the contiguous structure, so as to be membranous. M. Laennec has seen a cartilaginous transformation of the mucous membrane of the urethra; M. Beclard of the mucous membrane in the vagi- na, attended with prolapsus uteri, and also of the prepuce of an old man who had a phymosis from birth. OF THE PERICHONDRIUM. All the cartilages, except the articular ones, are invested by a membrane called perichondrium, (perichondre.) It is best seen on the larynx, and on the cartilages of the ribs. v Its struc- ture is fibrous, and corresponds so fully with that of the peri- osteum that it may be considered the same sort of membrane. It is, however, less vascular than the periosteum, and adheres to the cartilages with less force, owing to the fibrous connexion between them being not so abundant. Bichat's experiments prove that the cartilage is much less affected by the loss of this * Beclard, Anat. Gen. ARTICULAR CARTILAGES. 255 membrane, than the bone is by that of the periosteum: its uses are no doubt the same. OF THE ARTICULAR CARTILAGES. To this class we refer, exclusively, such as adhere by one surface to the articular facings of the bones, and present the other surface to the cavity of the joint. Every moveable, and some of the immoveable articulations, have their surface uni- formly thus incrusted, to a thickness varying from the fraction of a line in the smallest joints, to one line in the largest. The cartilage itself is rather thinner near the margin of the articular surface, when the latter is convex, than it is near the centre; on the contrary, when the surface is concave, the cartilage is thick- est near its periphery. These cartilages, when subjected to a, maceration of six months, are stripped of the reflection of synovial membrane, which covers their articular surfaces, and are resolved into fibres, one end of which adheres to the bone and the other end points to the joint. If the preparation be then dried, the dis- tinction of fibres becomes more manifest. The most successful injections, closely examined with a mi- croscope, demonstrate the defect of blood vessels in them. The vessels are uniformly seen to terminate at the circumference of the cartilage and at the face which adheres to the bone, but ne- ver to penetrate it. Their organization is, therefore, extremely simple, and such as subjects them to but few morbid alterations. When partially removed from the bone the latter occasionally reproduces them, but the edges of the new and of the old pro- duction do not unite. I have, in cases of inflammation of the joints, seen the fibres of these cartilages much longer than usual and detached from each other. When a joint is laid open by a wound, and suppurates, the cartilage softens and disappears from the circumference to the centre.* * Bichat, Anat. Gen. The same author speaks of the idiopathic ulceration of the cartilage, as a result of its inflammation. Dr. Physick, whose experience is equal, denies both. 256 SKELETON. CHAPTER II. OF THE FIBRO OR L1GAMENTO-CARTILAGINOUS SYSTEM. This set of organs (Systtme fibro-cartilagineux) has been placed by anatomists, indiscriminately in the cartilaginous or in the ligamentous systems, in consequence of its participating in the characters of both; it, however, from its importance, should have a distinct position. There are three varieties of this system. The first presents itself in the membranous state, and is represented by the external ear, by the alae of the nose, by the cartilage of the eye-lids, and by the trachea. The se- cond is represented by the inter-articular cartilages of the move- able articulations, as of the knee, the wrist, lower jaw, and also by the inter-vertebral matter which holds the bodies of the ver- tebrae together. And the third is represented by the trochleas and sheaths, formed on the surface of bones for the gliding of tendons. The principal constituent of this system is a strong fibrous matter, which is intermixed with the cartilage, and has in some places its surface covered by the latter. The fibres even by su- perficial observation may be traced in various directions: in some places they are parallel; in others intermixed and crossed very much; in others concentric. Their strength is of the first degree. The cartilaginous part fills up the intervals between the fibres, and gives to the whole structure its whiteness and elasticity. The Fibro-cartilages may be converted by the action of hot water into gelatine, but the process is slower than in the sim- ple cartilage. The membranous, or first variety, differs however from the other two in this respect; for if it can be reduced at all into gelatine, the quantity it yields is not perceptible. This system is destitute of perichondrium, with the excep- tion of the first variety, in which it is distinguishable; but the others either adhere to the bone, or are covered by a synovial LIGAMENTOUS TISSUE. 257 reflection; their margins adhering in such cases to the contigu- ous ligamentous structure. There is a very small quantity of cellular tissue in this sys- tem. Artificial injection manifests but few blood vessels in it; if the animal, however, be strangled for the purpose, the blood by accumulating in the capillaries becomes sufficiently apparent. CHAPTER III. OF THE LIGAMENTOUS OR DESMOID TISSUE. SECT. I. The Desmoid Tissue, (Textus Desmosus, Systeme Fibreux,) is very generally diffused in the human body, has a very close connexion with the cellular texture, and is continuous with it in divers places. It may be known by its whiteness, the firm- ness and unyielding nature of its materials, and its fibrous ar- rangement. It is most commonly employed in fastening the bones to each other at their articulations, and in enveloping the muscles, but it is also applied in many other ways. Its ap- plication in the former is our present object, but before that is particularly noted, it will be useful to enter into some general considerations in regard to its intimate structure, and the obser- vations now made can be applied on all other occasions when this tissue is in question. A desire to generalize, and consequently to simplify, has in- duced anatomists to seek for some fountain or source from which all the reflections and applications of the desmoid tissue might be traced. The Arabians thought that the dura mater was this source; and the error was sanctioned for a long time by the au- thority of Sylvius. The celebrated Bichat, in tracing the con- nexions of this tissue, finding that all its points of application might be traced either mediately or directly to the periosteum, considered the latter as its centre, as the heart is the centre of Vol. 1—33 258 SKELETON. the circulation, and the brain of nervous energy; not that he thought the periosteum radiated its influence on all its depenj dent organs, but because anatomical inspection demonstrated all the fibrous organs to be connected with it, and communicating through it with each other. The late Professor Bonn, of Am- sterdam, reversed the idea of Bichat, and considered the aponeu- roses of the extremities, and of the trunk, which send their par- titions between the muscles, and down to the periosteum and joints, as the much desired centre of the desmoid system. The latter idea has been reiterated by others, and the supposed ema- nations from the superficial aponeuroses diligently traced. As means of studying the position and connexions of parts, not- withstanding the construction is a very forced one, which makes desmoid tissue cellular membrane, and cellular membrane des- moid tissue, alternately, so as to suit the arrangement of the anatomists, instead of that of nature; yet, any or all of these plans have their use, and may be followed advantageously, after the study at large of the human fabric. The desmoid tissue is essentially fibrous, but without a uni- form arrangement, as its fibres are either parallel, crossed, or mixed. In some places the fibres are very compact, and sepa- rate with difficulty, but generally prolonged maceration will cause them to part into filaments as fine as the thread of the silk-worm. Anatomists differ in regard to the ultimate struc- ture of these fibres. By M. Chaussier they are thought to be primitive and peculiar; Mascagni* supposed that they were lymphatics enclosed in a vascular web; Isenflam, that they were cellular substance imbued with gluten and albumen. And M. Beclard, observing that maceration resolves them into a species of mucous or cellular substance, teaches that they are the latter in a condensed state. Bichat's opinion is probably correct that the tissue is peculiar, and that maceration only brings into view the cellular substance which unites its fibres. Though macera- tion and chemical management evolve some striking coinci- dences with cellular membrane, yet in the natural and ordinary state there are some very strong points of difference from it. Among these may be remarked its great want of elasticity, which causes it to tear sooner than to stretch; and in general * Prodromo della Grande Anatomia. LIGAMENTOUS TISSUE. 259 anasarca, its being only very partially affected, merely rendered a little more moist and tumid, which even then may arise from the small quantity of cellular substance in it. Many parts of it, however, are unaffected in the latter way, as the tendons and their sheaths. This tissue naturally contains a considerable quantity of water, which it loses by exposure to the air; it then is much reduced, and becomes hard and yellowish, and is made semi-transparent by being put into spirits of turpentine. The desmoid tissue, by being subjected to the heat of boiling water, contracts, becomes more solid, and is elastic; but if it be continued there, it gradually softens, becomes semi-transparent, and gelatinous. The mineral acids reduce it to a pulpy state, and if concentrated, will dissolve it entirely. The alkalies loosen its texture, cause the fibres to separate easily, and to assume a diversity of colours. It putrifies but slowly, in this respect be- ing next to the cartilages. The strength of this texture is remarkable, and adapts it to the sustaining of enormous weights; a faculty which is conti- nually in requisition, both to retain the articular surfaces of bones in contact, and the muscles and tendons in their places. It is well known that the patella, the olecranon, and the os cal- cis, break frequently before their tendinous attachments will give way. In the history of punishments, where criminals have been fastened to four horses, it is said that it has been found necessary to use a knife to assist in their disarticulation. All these phenomena occur when abrupt violence is resorted to, so little are the ligaments disposed to yield; but when the causes of distention act slowly and gradually, as in dropsies of the joints, the fibres separate, and are sometimes completely disu- nited. When the distending cause ceases to operate in the lat- ter case, the ligaments have the power of contracting in the same gradual way, and of restoring themselves. Some of the desmoid tissues, besides having their fibres sur- rounded and their interstices occupied by cellular substance, contain a very small quantity of oily or fatty matter. This is not very obvious in their recent state; but, by drying them, it will be seen in small quantities on their surface, like a greasy exudation; this probably comes from the cellular substance in them. They are furnished but sparingly with blood vessels, 260 SKELETON. which, for the most part, are capillary. The periosteum and the dura mater are, however, exceptions to this rule. Lym- phatic vessels have been observed in some of them, but it is doubtful whether they generally have nerves.* The sensibility of this system is extremely obscure, and is not manifested under the usual mechanical and chemical irritants; it ftiay, however, be elicited by communicating to the joints a twisting motion, as the experiments of Bichat prove. Inflam- mation augments their sensibility, in which case it becomes ex- tremely acute, as in gout and rheumatism, or any other cause productive of it. SECT. II.--OF THE LIGAMENTS OF THE JOINTS. The ligaments, (ligamenta,) properly speaking, are those or- gans which tie the bones together, and in the moveable joints are either capsular (capsules fibreux) or funicular, (ligamens fibreux fasciculaires.) The first are like a bag open at the ends, at either of which the articular extremity of a bone is in- cluded. These are much more complete in some joints than in others; the shoulder and the hip joints afford the most perfect examples; in other joints they are divided into irregular fasci- culi of fibres, permitting the synovial membrane to appear in their interstices, and sometimes they are still more widely se- parated. The funicular ligaments are mere cords, extending from one bone to another; some of them are flattened, some rounded,and others oval or cylindroid. They are variously placed; in some instances they are within the capsular ligament, and in others, on its outer surface, and sometimes so blended with it as not to be separated without an artificial dissection. Their names are derived either from their position or shape, and are generally suf- ficiently appropriate. SECT. III.—OF THE SYNOVIAL ARTICULAR CAPSULES. Each moveable articulation is lined by a membrane, (Mem- brane Synoviale,) reflected over the internal face of the capsu- • Beclard, Anat. Gen, SYNOVIAL ARTICULAR CAPSULES. 361 lar ligament and the articular cartilages. This membrane is a perfect sac; and, unlike the capsular ligament, has no opening in it. It is remarkably distinct where it is not attached to the articular cartilages; and, by being inflated, is caused to protrude in small vesicles, or pouches, between the fasciculi of the liga- mentous structure. Its connexion with the cartilage, and its continuation over it, are not quite so obvious, and require more management to demonstrate: it is, indeed, so thin and transpa- rent at this part, and adheres so closely, that its existence there has been questioned, but may be proved in a variety of ways. By maceration it becomes so loose, that, with a pair of forceps, shreds of it may be raised along the whole extent of the carti- lage. If a flap of cartilage be raised up by a knife, its base being left attached, in attempting to tear away the base it will be found that the synovial membrane is continued from this base to the contiguous cartilage. Saw a bone through to its articular car- tilage, then tear through the cartilage gently, in which case the continuity of the synovial membrane will also be manifested. From these several proofs the fact is established, that the sy- novial membranes are bags, closed at both extremities, and dif- fer thereby from the capsular ligaments. The synovial capsules are liable to a fungous degeneration which occurs equally upon the cartilaginous and capsular por- tions of them. Factitious bridles sometimes form in the joints, attached indiscriminately to either portion of the synovial mem- brane. M. Beclard says, that protracted inflammation will, final- ly, redden the cartilaginous portion, and that it extends from the circumference to the centre, the hues being lighter the nearer it is to the latter. It has not occurred to me to meet with this proof; though I have made frequent dissections in subjects, of inflamed joints, the redness has always ceased at the margin of the articular cartilage. Dr. Physick's experience, most va- luable on all occasions, affords support to my own. Some years ago I had an opportunity of investigating, somewhat fully, this point, in a subject, all of whose large joints were in a state of inflammation. These synovial capsules, or membranes, are white, thin, se- 262 SKELETON. mi-transparent, and soft. Wherever there is a deficiency of capsular ligament they adhere to the contiguous cellular sub- stance, and are so blended with it as to appear absolutely con- tinuous. Dissection, inflation, and maceration, prove them to be laminated, and develop their structure in such a way that it re- solves itself into a cellular tissue, the more interior layers of which had been in a very compacted state. In all this they re- semble the serous membranes, generally, and are ranked among them; Bichat, therefore, considers them only as an interlace- ment of absorbents, and of exhalents. But, for the farther ex- position of this point, see the article on the Serous Membranes. The synovial sacs have, on their outer surface, but projecting into the cavity of the joint, adipose cushions of different sizes, called the Synovial Glands of Havers, from which, till lately, it was supposed that the lubricating liquor of the joints is exclu- sively secreted. These cushions have their projecting margins fringed and unusually vascular, and occupy the small spaces left between the articular faces of the bones. As they are co- vered by the synovial membrane, they, no doubt, assist in the secretion of the synovia. The moveable articulations are all furnished with the fluid called Synovia; this name was given to it by Paracelsus, from its resemblance to the albuminous part of an egg, to the con- sistence and colour of which it has a close affinity, and, like it, is thick, ropy, and somewhat yellowish. The chemical analysis of it indicates the presence of water, albumen, and a kind of in- coagulable mucus. It was once supposed to be a mixture of serum, with the adipose matter of the bones, which found its way into the joints by transudation; but as it contains upon ex- periment no oil, the opinion is evidently erroneous. It is se- creted from the whole internal surface of the synovial membrane, and, perhaps, in greater quantities from the fringed fatty cushions in the joints in consequence of their increased vascularity. M. Beclard teaches, that it is neither a follicular nor a glandular se- cretion, nor a transudation, but a perspiration, in which a perfect equilibrium is kept up between its exhalation and its absorption. Its use is to diminish friction, and, consequently, to facilitate the sliding of the bones upon each other. ARTICULATION OF THE LOWER JAW. 263 CHAPTER IV. ARTICULATION OF THE LOWER JAW. The articular surface, here, is formed by that portion of the glenoid cavity anterior to the fissure, and by the condyle of the lower jaw. Each surface is covered by thin cartilage; and a thin, loose, irregular, fibrous, capsular ligament, arises from the articular margin of one bone, to be inserted into that of the other. Besides this, there are four other ligaments for strengthening the joint, an inter-articular cartilage, and two synovial mem- branes. The External Ligament (Membrana Jlrticularis Ligamen- tosa) arises from the inferior margin of the jugal or zygomatic process of the temporal bone, and from the anterior side of the meatus externus, and is inserted into the neck of the condyloid process. It is somewhat triangular, having the base upwards. Just in advance of this, and separated from it by a small fissure, is another triangular ligament, the discovery of which is claimed by Caldani.* It arises from the anterior part of the inferior margin of the zygomatic process of the temporal bone, and is inserted into the neck of the bone in advance of the other. The Internal ligament (Lig. Maxillae Laterale) arises from the extremity of the spinous process of the sphenoid bone, and from the posterior margin of the glenoid cavity, and going downwards and outwards, is inserted into the spine bordering the posterior mental foramen, and for some distance lower down on the ramus of the jaw. It is placed between the two ptery- goid muscles, and is in contact with the maxillary vessels and nerves, as they run between it and the condyle to the posterior mental foramen. It is thought by Caldani to be not so useful in restricting the motion of the jaw forwards, as in holding the vessels and nerves, and regulating their position, lest in the va- * Tabul. Anat. Venetiis/1802, 264 SKELETON. rious motions of the lower jaw they should be displaced and injured. The Stylo Maxillary Ligament is thinner than the above. It arises from the external side of the styloid process, and is in- serted into the posterior margin of the jaw, near its angle, be- tween the masseter and internal pterygoid muscles. The sty- lo-glossus muscle is much connected with it, and is thereby as- sisted in elevating the base of the tongue. There are two synovial membranes, the one reflected between the glenoid cavity and the upper surface of the inter-articular cartilage, and the other between this latter substance and the condyle of the lower jaw. They may be seen at different points protruding between the fibres of the capsular ligament. The inter-articular cartilage, by being placed between the two synovial membranes, separates completely the two bones. Above, its surface corresponds to the convexity of the tubercle of the temporal bone, and to the glenoidal cavity; below, it is simply concave for receiving the condyle. It is thicker at the circumference than in its middle, and at the posterior than the anterior margin. Sometimes it is open in the centre, in which case the two synovial membranes run into one another. Its structure is fibro-cartilaginous. It moves very readily back- wards and forwards. On the posterior face of the capsular ligament, I have found in several cases, indeed, on all occasions of special examination for it, since the first observation, an erectile tissue or structure resembling the corpus cavernosum penis. It has not been filled with blood like the latter, but is, probably, an arrangement for giving great mobility forwards to the lower jaw. The movements of this bone may be simply hinge-like, by its depresssion, in which the mouth is regularly opened; or, by the action of the pterygoid muscles, it may be slid forwards. When the muscles of but one side act, a species of rotation is communicated; in which one condyle advances on the tubercle LIGAMENTS OF THE SPINE. 265 of the temporal bone, while the other reaches to the back part of the glenoid cavity. The looseness and length of the capsu- lar ligament of the articulation, along with the extreme facility of motion from the interposition of a moveable cartilage, con- tribute very materially to this movement. The sliding back- wards and forwards of the intermediate cartilage of this arti- culation, during mastication, sometimes produces a cracking, audible to the by-standers; and extremely annoying to the in- dividual who is the subject of it, from the noise being so near his ear. Some persons are liable to a spontaneous dislocation of this bone, from yawning too widely. I am disposed to believe, that, in such cases, the accident arises from the posterior boundary of the glenoid cavity, (as established by that margin of the temporal bone which is continuous with the vaginal process, and forms a part of the meatus externus,) being more advanced and higher than usual; in consequence of which, whenever the bone is depressed to a certain point, its neck strikes against this ridge, and not being able to go farther hack, the ridge acts as a fulcrum, and starts the condyle over the tubercle of the tem- poral bone into the zygomatic fossa. The fact is certain, that very strongly marked differences of the glenoid cavity, in this particular, occur in different individuals. CHAPTER V. OF THE LIGAMENTS OF THE SPINE. Ligaments of the Bodies of the Vertebrae. 1. Inter-vertebral Substance, (Ligamenta Litervertebralia, Ligamens Inlervertebraux.)—The bodies of the true vertebrae are united by a substance blending the nature of ligament and that of cartilage, and, therefore, called fibro or ligamento carti- laginous matter. It occupies all the space between the conti- guous bodies of the vertebrae, and adheres most closely to their * Vol. L—34 266 SKELETON. substance. This inter-vertebral matter increases successively in thickness, as it is placed lower down on the spine, whereby the lumbar vertebrae are mutually at a much greater distance than any others. The curvatures of the spine, as stated, depend considerably upon the arrangement of this substance: between the vertebrae of the neck it is thicker at its anterior margin than at the posterior; on the contrary, between the dorsal vertebrae it is thinner in front. In the loins, it is again much thicker in front than behind, and this feature is unusually marked between the last lumbar vertebra and the sacrum. This inter-vertebral matter is formed of concentric lamellae, the texture of which is ligamentous. These lamellae are more abundant anteriorly and laterally than behind. Their fibres cross in every direction, leaving between them interstices or cells, filled with a soft, pulpy substance. This substance is not very obvious near the circumference, but in approaching the centre, it becomes more and more abundant, as the interstices are larger, until the centre seems to be constituted almost en- tirely by it. The pulpy mass in the centre is in a state of con- siderable compression, which may be proved by separating the bodies of adjoining vertebrae, or by making a vertical sec- tion through them; in which case the pulpy mass will be freed from compression, and will rise up into the form of a cone. This experiment will succeed remarkably well in the loins; from which it is evident, that this mass is a soft and elastic ball, on which the bodies of the vertebrae play. The pulpy matter is proportionately much more abundant in infancy than in the subsequent periods of life; it is also much softer, whiter, and more transparent. In advanced life there is great diminution of its volume, as well as of its elasticity, which accounts, in some measure, for the comparative stiffness of the spine in old people. The fibrous part in them is always more abundant, and is much disposed to ossify. When the trunk is kept erect for several hours in succession, it becomes shorter, from its weight bearing upon the inter-vertebral mass; but a short period of rest in the horizontal position, restores it to its original length. 2. Anterior Vertebral Ligament, (Fascia Longitudinalis LIGAMENTS OF THE SPINE. 267 •Anterior, Ligament Vertebral Anterior.)—This ligament is placed on the front part of the spine, and extends from the se- cond vertebra of the neck to the first bone of the sacrum, inclu- sively. It increases gradually in breadth, from its commence- ment to its termination, but is not every where of the same thickness; for it is thin on the neck, thicker in the thorax, and again becomes thin in the loins: in the latter, however, it is strengthened by an accession of fibres from the tendinous crura of the diaphragm. This ligament adheres very closely to the inter-vertebral sub- stance, and to the projecting margins of the bodies of the verte- brae, but less closely to the middle or concave parts of the latter. Its fibres do not run out its whole length, for the more superfi- cial extend from one vertebra or inter-vertebral substance, to the fourth or fifth below: the middle ones extend to the second or third below; and the deepest seated are applied between the proximate vertebrae only. In general, more of the fibres are inserted into, and arise from the fibro-cartilaginous matter than the bones. In several parts, but particularly in the neck, small slips are sent off obliquely to the vertebra below. The laminae of this ligament leave intervals between them for the passage of blood vessels. Beneath the anterior vertebral ligament are found a great many short and insulated ligamentous fibres, extended ob- liquely from one vertebra, to another which is contiguous. These fibres have different directions, and cross each other at acute angles; they adhere very closely to the fibro-cartilaginous matter, and leave interstices between themselves, through which the anterior vertebral ligament adheres to the same substance. Moreover, there are at the sides of the bodies of the vertebrae, a number of short straight fibres, passing from the edge of the bone above to the edge of the bone below. 3. Posterior Vertebral Ligament, (Ligamentum Commu- nis Posterior, Ligament Vertebral Posterieur.)—This is placed on the hind part of the bodies of the vertebrae, within the spinal canal, and extends from the cuneiform process of the occiput just beyond the foramen magnum to the os coccyges. It is more narrow and thick in the thoracic vertebrae than else- 2GS SKELETON. where. At each inter-vertebral substance it increases in breadth and adheres more closely, whereas, opposite the body of a ver- tebra it is narrower and more loose, by which arrangement a kind of serrated or unequal edge is formed on each side. This ligament is more dense and compact than the anterior, and presents a smooth, shining surface, resembling a tendinous expansion. Its fibres, also, do not run individually the whole length of the spine, but are in laminae; the more superficial of which have their fibres inserted into the fourth or fifth inter- vertebral substance or vertebra, below their origin. The middle laminae are inserted into the second or third below, and the deep- ly seated into the first below. The blood vessels do not penetrate the ligament, but pass by its sides into the vertebrae. The su- perior extremity of this ligament going from the second verte- bra to the margin of the foramen magnum, is sometimes consi- dered as distinct. Ligaments of the Processes of the Vertebrae. I. Articulation of the Oblique Processes.—These processes are faced with cartilage, and a synovial capsule is displayed upon them so as to shut up completely the cavity of the articulation. The capsular ligament is not uniform and fully developed, but is represented by a few irregular fibres, passing from one bone to the other. 2. Articulation of the Spinous Processes.—With the excep- tion of the neck, ligamentous fibres are found to occupy the spaces between all the spinous processes, by passing from the spinous process above, to the spinous process below. Muscles supply their places in the neck, and in the upper part of the thorax. These ligaments have much of a cellular structure above, but in their descent they become more ligamentous and large, till, in the loins, they assume a very decided character, and have a quadrilateral shape. At the extremities of the spinous processes there is, also, a ligamentous band, belonging to the dorsal and lumbar vertebrae: commencing at the seventh cervical, it terminates on the spi- nous processes of the sacrum. It is thin in the back, but on the LIGAMENTS OF THE SPINE. 269 loins it is very thick, and so blended with the tendinous origins of the muscles, that it is not very distinguishable from them. The fibres of which it consists are of unequal lengths, being extended between two, three, four, or five vertebrae, according- ly as the fibres are superficial or deep-seated. 3. Owing to the shortness of the spinous processes of the neek, an arrangement exists there called Ligamentum Nucha?, (Ligament Cervical,) or the Descending Ligament of Diemer- broeck. This ligament, though continuous with the one last described, may be considered, for the sake of perspicuity, as distinct. It begins, therefore, at the seventh cervical spine, as- cends between the muscles of the opposite sides of the neck, and is inserted into the posterior occipital protuberance. It is blend- ed very much with the tendons of muscles, and is distinguished from them with some difficulty, occasionally. Its posterior mar- gin is thick, but the anterior is a thin membranous expansion, which runs to the ends of the spinous processes of the cervical vertebrae, and to the ridge of the occipital bone, leading from the occipital protuberance to the foramen magnum. The li- gamentum nuchae, therefore, forms a complete septum between the muscles of the opposite sides of the neck, and is continuous with the sheaths in which they play. In quadrupeds it is re- markably strong; but in man, who, from the proportions of his head and his erect position, keeps the head nearly in equilibrium, it is comparatively feeble. 4. Articulation of the Bony Bridges of the Verlebrte.— The intervals between the vertebrae, at the posterior part of the spinal canal, are filled up by the yellow ligaments, (Ligamenta Flava,) so called from their peculiar colour. These intervals exist between all the true vertebrae, being bounded laterally by their oblique processes, and are very considerable in the loins, particularly that below the last vertebra; they are not so large in the neck, and are still smaller in the back. Their shape va- ries considerably in the several portions of the spine. The yellow ligaments are two in number, forming a pair in each of these intervals; and they approach, behind, at an angle, 270 SKELETON. in a line with the spinous processes, but are kept separated by a small vertical fissure filled up with cellular substance. They extend to the oblique processes: laterally are connected to the anterior face of the bony bridge of the vertebra above; whereas, they are inserted into the superior margin of that of the vertebra below. From this arrangement, the yellow ligaments may be best seen on the side of the spinal canal. The angle which they form, behind, is continuous with the ligaments between the spi- nous processes. These yellow ligaments are smooth and shining on their an- terior surfaces, but behind they are rough and unequal. Their fibres are numerous and extremely compact, their strength is, therefore, very great. Their elasticity is well marked and pe- culiar to them, and assist greatly in erecting the spine when it has been curved forwards. Bichat says that there is but little cellular tissue between their fibres; that they are dissolved with extreme difficulty in boiling water, and resist its action to such a degree, that it is manifest they contain much less gelatine than the greater number of analogous organs. The first pair of yellow ligaments is between the second and third cervical vertebrae, and the last between the last lumbar and the sacrum; there are, consequently, only twenty-three pairs in all. Particular Articulations of the Spine. 1. Articulation of Occiput with Atlas.—The Anterior Ligament is placed at the anterior part of the occipital foramen and extends from it to the corresponding edge of the atlas. On its centre in front is a fasciculus, which being narrow and somewhat rounded, descends from the middle of the cuneiform process to terminate in the tubercle on the front of the atlas* and consists in parallel fibres. The remainder is called by Cal- dani, Membrana annuli anterioris atlantis, (Ligament occipito- alloidien anlerieur.) It occupies and shuts up the whole space between the basilar process of the os occipitis, from which it takes its origin near the occipital foramen; and the anterior arch of the atlas, in the superior margin of which it is lost: in it are many oblique fibres, which run from within outwards. LIGAMENTS OF THE SPINE. 271 The posterior Ligament is placed at the back part of the oc- cipital foramen, and extends from it to the corresponding edge of the atlas. It is called by Caldani, Membrana annuli poste- rioris atlantis, (Ligament occipilo-atloidien posterieurf) and arising from the whole posterior margin of the occipital foramen between the condyles, it is extended to the upper contiguous margin of the atlas, so as to fill up completely this space. Bi- chat says that it also consists in two laminae, the anterior of which is fibrous, and runs into the dura mater of the spine instead of into the bone; the posterior is of a much looser texture, and re- sembles common cellular substance. A part of this membrane runs obliquely from the transverse process of the atlas to the part of the occiput just beneath the insertion of rectus posticus minor. The articulating surfaces of the condyles, and the superior oblique processes of the first vertebra, are covered with carti- lage, and furnished with a synovial membrane arising from their margins. On the exterior of the synovial membrane there are irregular ligamentous fibres going between the bones, and form- ing a capsule. 2. Articulation of the second Vertebra with the occiput, and with the first.—The second vertebra has no articular sur- face joining the occiput, but some strong ligaments are passed between them. When the posterior vertebral ligament is re- moved at its commencement from the occipital bone, we see on each side of it, and beneath it, ligamentous bands (Lacerti Liga- mentosi,) coming from the internal face of the os occipitis, to be affixed to the body of the second vertebra behind. Some of these fibres arise from the margin of the occipital foramen, and others from the internal face of the condyloid processes.* They are joined at their external margins by a few fibres from the first verebra, near its upper oblique process. The Transverse Ligament (Ligamentum Transversale At- lantis, Ligament Transverse,) is placed immediately behind the processus dentatus, and divides the atlas into two unequal • Caldani, Icon. Anat. Explicato, vol. i. p. 255. 272 SKELETON. rings by being stretched from one side to the other. It is larger in the middle than at the extremities, and has the latter inserted into the little tubercle at the internal side of the atlas, between the upper and the lower articular surfaces. It is a thick, strong fasciculus of fibres, and binds the processus dentatus so as to form for it a sort of collar, amounting to about one-fourth of a circle. The superior appendix of this ligament arises by a broad base from the anterior margin of the foramen magnum, and termi- nates below by a narrow end in the upper margin of the trans- verse ligament. The inferior appendix arises from the lowrer edge of the transverse ligament, and is attached, by a some- what converging end, into the posterior face of the body of the vertebra dentata. The surfaces of contact belonging to the processus dentatus, and to the anterior ring of the atlas, are covered with cartilage, and have a synovial membrane, so as to form a perfect joint called the vaginal ligament. A joint with a distinct synovial membrane is, in like manner, formed between the posterior face of the processus dentatus and the anterior of the transverse li- gament, where they come into contact. The Oblique or Moderator Ligaments (Lig. Lateralia, Li- gamens Odontoidiens) are two, one on either side of the tooth- like process. They may be seen most advantageously by cutting through the transverse ligament, and arise from the sides and summit of the processus dentatus, to be inserted into the inter- nal margin of the occipital condyle. They are thick, short, and strong, and consist in parallel fibres; their lower margin has been considered as a distinct ligament by Weitbrecht, and described by him as coming from the neck of the process. There is some cellular tissue at the front, in which the process revolves. The Middle Straight Ligament, (Lig. Medium Rectum, Li- gament droit Moyen,) or Occipito-Dentate, arises from all that part of the summit of the processus dentatus anteriorly which is between the moderator ligaments, and is inserted into all that part of the inferior circumference of the foramen magnum be- tween the insertion of the moderator ligaments. It is a thin ligamentous membrane, disposed to form in its middle a verti- LIGAMENTS OF THE SPINE. 273 cal fissure, separating its two halves. It cannot be seen well, unless the whole membrana annuli anterioris be dissected away, and the anterior bridge of the first vertebra sawed off, it will then be found immediately behind the bursa of the processus dentatus. It is separated from the superior appendix of the transverse ligament by a layer of condensed fatty substance. This ligament should not be confounded with the superior ap- pendix of the transverse ligament, nor with the beginning of the posterior vertebral ligament, as has been done by Bichat and others. The difference is well established by Caldani, as it lies deeper than either of them, when viewed from the vertebral cavity; though, from the close connexion of the fibres of the ligaments among themselves, as well as with others, the mistake may readily occur. The Articulation between the oblique process of the first and of the second cervical vertebrae is very moveable, as the atlas is permitted to revolve around the processus dentatus to the amount of one-fourth of a circle at least. This articulation has a synovial capsule which is strengthened by an anterior and by a posterior ligament. The anterior ligament of the articulation between the oblique processes arises from the inferior margin of the atlas and from its anterior tubercle, and is inserted into the base of the pro- cessus dentatus, and into the front of the body of the second vertebra. The fibres of the latter insertion are longer and fre- quently distinct from the first. The posterior ligament is placed between the first and second vertebrae behind, and is connected to their contiguous margins so as to fill up the interval between them, and to supply the place of the yellow ligaments. It is extremely loose and thin, so as not to interfere in the movements of the vertebrae, and is * almost of a cellular structure. The synovial membrane of these oblique processes is unusual- ly lax, and is reflected from the margin of the one articular sur- face to the other. It is in contact in front with the anterior ligament; behind with the posterior and with much cellular substance; internally with the ligaments within the spinal canal and externally with the carotid artery. The latter obtains from Vol. I.—35 274 SKELETON. it a serous covering, without which, according to Bichat, it would be bathed in the synovial fluid. CHAPTER VI. OF THE LIGAMENTS OF THE PELVIS. The mode of junction between the sacrum and the last lum- bar vertebra, is, in every respect, the same as that described for the bones of the spine generally, with the addition of a ligament on each side, sometimes met with, called sacro-vertebral, which arises from the transverse process of the last lumbar vertebra, and going obliquely downwards, is inserted into the superior part of the sacrum by blending itself with the anterior fibres of the sacro-iliac junction. The Sacrum is united to the coccyx by a fibro-cartilaginous substance, resembling that between the bodies of the true ver- tebrae, with the exception of there being less pulpy matter in its centre, and of its fibrous lamellae being more uniform. The bones of the coccyx are also united with one another in the same way; in consequence of which they are very flexible till the approach of old age. The Anterior Coccygeal Ligament, (Lig. Sacro-coccygeum Anterius) is placed on the fore part of the latter bone; runs its whole length, and arises from the inferior extremity of the sa- crum. Its fibres are rather indistinct, from their being blended with fat; on the lateral margins of the coccyx they are rather better marked. The Posterior Coccygeal Ligament, (Lig. Sacro-coccygeum Posterius,) as its name implies, is placed on the back part of the coccyx. It arises from the inferior margin of the spinal canal of the sacrum, and forms a sort of membranous expansion, vhich passes the first bone of the coccyx, and is inserted into LIGAMENTS OF THE PELVIS. 275 the second. There are also a few other ligamentous fibres con- necting the bones of the coccyx. The Ilio Lumbar Ligament (Lig. Ilio Lumbare) arises from the transverse process of the last lumbar vertebra, and from its inferior oblique process, and going outwards is inserted for two inches into the crista of the ilium, just above the posterior su- perior spinous process. It is often blended with adipose matter which separates it into several fasciculi. Caldani describes it as two ligaments, making a distinction between the one part from the transverse, and the other from the oblique process. The Sacro-Iliac Articulation is formed by the corresponding surfaces of the sacrum and ilium. Each bone is incrusted with its own cartilage, the one on the sacrum being somewhat more thick. Their surfaces are slightly rough, and between them ex- ists a thick yellow fluid in a very small quantity, which lubri- cates them, and is more abundant in early life. The Sacro Spinous Ligament (Lig. Sacro Spinosum) is placed superficially on this articulation behind. It is very strong, flat, long, and perpendicular. It consists of two laminae, of which the more superficial arises from the posterior supe- rior spinous process of the ilium, and is inserted into the fourth transverse process of the sacrum. The deep-seated lamina arises from the same point, and is inserted into the third trans- verse process of the sacrum. Bichat describes, connected with the inferior margin of this ligament, a fasciculus, which comes from the posterior inferior spinous process of the ilium. The Sacro-Iliac Ligament (Lig. Sacro-Iliacum) is next to the articular faces of the bones. It surrounds the joint, but is much stronger on its posterior face. It consists in an assem- blage of ligamentous fasciculi, some of which have obtained, by the writers on Syndesmology, particular names, but which it would scarcely add to the student's information to designate. On the front of the joint this ligament is uniform, and consists of a plane of short, strong fibres, passing from the margin of one bone to that of the other. But, on the posterior surface, it 276 SKELETON. is much more irregular, and arises from the two first eminences near the lateral margin of the sacrum, and from that surface of the sacrum between these eminences and its articular face. From thence the sacro-iliac ligament goes to be inserted into the rough surface of the ilium, immediately behind its articu- lar face; it fills up there a considerable space, and, from its po- sition, must be extremely irregular. Its strength is so great, that in forcing the joint, the ligament does not rupture, but parts preferably from the surface of the ilium, and sometimes brings with it a lamella of bone. The bones of the pelvis are also fastened by two other very strong ligaments, the sacro-sciatic. The Posterior Sacro-Sciatic (Lig. Sacro-Ischiadicum majus) is the most considerable of the two. It arises from the poste- rior inferior spinous process of the ilium, from the margin of the sacrum below this bone, and somewhat from its posterior surface, and from the first bone of the coccyx. It goes down- wards and outwards, becomes thicker in its middle, but nar- row; it then spreads out, and is inserted along the internal mar- gin of the tuberosity of the ischium. Its anterior extremity is extended along the internal face of the crus of the ischium for some distance, and has the obturator internus muscle adhering to it. Its fibres, where they converge from their origin, are se- parated into planes by masses of fat and by blood vessels. The Anterior Sacro-Sciatic Ligament (Lig. Sacro-Ischiadi- cum minus) is much smaller than the other, and is placed in front of it. It arises from the margin, and somewhat from the posterior surface of the sacrum, below the ilium; and from the lateral margin of all the bones of the coccyx. The fibres con- verge, and are inserted into the spinous process of the ischium, by embracing it. The fibres constituting its base, have their fasciculi separated by cellular adipose matter and by vessels, and are also intermingled with the fibres of the coccygeus mus- cle, and of the posterior sacro-sciatic ligament. The two sacro-sciatic ligaments supply, in some degree, the place of bone, and form a part of the inferior lateral parietes of the pelvis. They convert the sciatic notch into a foramen, or, LIGAMENTS OF THE PELVIS. 277 rather, form with it two foramina; the upper and larger of which transmits the pyriformis muscle, the sciatic nerve, and the glu- teal blood vessels; while the lower, placed between the inser- tion of the two ligaments, transmits the obturator internus mus- cle, and brings the internal pudic artery into the pelvis. The Obturator Ligament (Membrana Obturatoria) is ex- tended across the foramen thyroideum, so as to close it up, with the exception of a foramen at its upper part, for transmitting the obturator vessels and nerves. It is a thin, but strong mem- brane, having its fasciculi of fibres passing in various directions, and arising from the margin of the foramen. It affords origin to many of the fibres of the obturator muscles. Sometimes portions of it are defective. The Articulation of the Pubes is formed between the bodies of the two ossa pubis. It consists principally in a fibro-carti- laginous matter, which has a strong resemblance to that of the vertebrae. When the bones are* torn apart by bending them forwards, the fibrous arrangement becomes very apparent, and is seen to consist in concentric lamellae, the fibres of which cross one another. Sometimes in the male, but most frequently in the female, the posterior third of the articulation is deprived of these fibres, in place of which we find, in the middle of the cartilage, a small longitudinal cavity, the surface of which is smeared with a kind of mucosity. There is no central pulpy matter in this articulation, as there is between the vertebrae. On its posterior surface it often makes a ridge projecting into the cavity of the pelvis. From frequent observations made in our dissecting-rooms, I have no doubt that this articulation is al- ways very much relaxed in the parturient and pregnant female, which is manifested not by the bones separating, but by their sliding upwards and downwards with great readiness. The sa- cro-iliac junction also becomes relaxed. It was upon the ob- servation of these facts, that the celebrated, but now exploded, Sigaultian operation was founded. The Anterior Pubic ligament it not very distinct. It lies in 278 SKELETON. front of the last articulation, and consists in a few oblique and transverse fibres going from the one bone to the other. The Sub or Inter-Pubic Ligament (Lig. Pubis Inferius) oc- cupies the summit of the arch of the pelvis. It is of a trian- gular form, about half an inch in breadth, and passes from the margin of the crus of the pubes of the one side, to a corre- sponding line on the other. It is remarkably strong, and is ra- ther more so below than above. It seems rather an extension of the ligament of the symphysis pubis, than a distinct struc- ture. CHAPTER VII. ARTICULATIONS OF THE THORAX. Posterior Articulations of the Ribs. As mentioned, in the account of the bones, the articulations here are double; being formed at one point between the heads of the ribs and the bodies of the vertebrae with the inter-ver- tebral matter; and, at the other, between the tubercles of the ribs and the transverse processes. In either case the respective surfaces are covered by articular cartilage, and have a synovial membrane. The first joint is the costo-vertebral, and the se- cond the costo-transverse. 1. The costo-vertebral articulation presents an anterior liga- ment, an inter-articular ligament, and two synovial membranes. The Anterior or Radiating Ligament, ILig. Capituli Costa- rum,) is fixed, as its name expresses, in front of the joint. It arises from the margin of the head of the rib by the whole breadth of the latter, and, diverging towards the spine, is fixed, by its superior fibres, into the vertebra above; by its inferior fibres, into the vertebra below; and, by its middle fibres, into the inter-vertebral substance. It is a thin, flat, fibrous mem- ARTICULATIONS OF THE THORAX. 279 brane, leaving intervals in it for the passage of blood vessels, and may, indeed, be considered as a capsule to the articu- lation, and is frequently described as such. The inter-articu- lar ligament passes from the ridge on the head of the rib, to a corresponding line of the inter-vertebral substance. It is short and strong, and divides the articulation of the head of the rib into two cavities, which have no communication. It is in consequence of the latter, that there are two synovial mem- branes to the head of every rib which has a double articular face; but the ribs which are articulated with a single vertebra, as the first, the eleventh, and the twelfth, have not the inter- articular ligament, and, therefore, only one synovial membrane. The synovial membranes are not very apparent, neither is the fluid abundant; the cavity is occasionally very small from the encroachment of the inter-articular ligament. Anchylosis occasionally takes place here, but it is much less frequent than in the anterior articulations of the thorax. 2. The costo-transverse articulation has, in addition to the joint formed between the tubercle of the rib and the end of the transverse process, several ligamentous fasciculi which pass in varied directions. The synovial membrane is much more distinct than in the preceding articulation, and contains more synovia. It is more loose, and is never anchylosed, except by disease. There are a. few fibres around it having the semblance of a capsule. The Internal Transverse Ligament (Ligamentum Transversa- rium Internum, or Costo- Transversarium Inferius,) arises from the inferior margin of the transverse process, between its root and external extremity, and, proceeding downwards and inwards, is inserted into the upper margin of the neck of the rib below. In many of the ribs there is a plane of ligamentous fibres paral- t lei with this ligament, but just behind, and arising from a more posterior situation of the transverse process to go to the neck of the rib, somewhat more towards the tubercle of the latter. It is designated by some writers as the posterior transverse li- gament, but the distinction between it and the lig. trans, inter- num is so slight that it scarcely seems necessary to consider them apart. It is much more conspicuous in the middle eight 280 SKELETON. ribs, and in extremely emaciated subjects; in others, it is ob- scured by cellular adipose matter around the heads of the ribs. The External Transverse Ligament (Ligamentum Transver- sarium Externum, or Costo-Transversarium Posterius) is a well- marked quadrangular plane of ligamentous fibres, placed on the posterior surface of the costo-transverse articulation. It arises from the extremity of the transverse process, and going out- wardly, is inserted into the proximate rib, just beyond its arti- cular tubercle. The Middle Costo-Transverse Ligament (Ligamentum Cer- vicum Costarum, or Costo-Transversarium Medium) is extended between and concealed by the neck of the rib and the contigu- ous transverse process, and cannot be seen well without sepa- rating them, or by sawing through their length. It is a collec- tion of fibres, somewhat irregular, resembling condensed cellu- lar substance, and slightly red. These posterior articulations, all require a patient dissection, as they are surrounded by small masses of adipose matter, have the intercostal nerves and blood vessels in contact with them before, and the muscles of the spine behind. The ligaments between the transverse processes and the ribs are, of course, not found in the eleventh and twelfth, from the bones not touching there. Besides what has been described, an aponeurosis or ligamen- tous membrane is extended from the transverse'process of the first and second lumbar vertebrae, to the inferior margin of the last rib. A ligamentous membrane is also found near the spine, extended between the contiguous margins of the two last ribs. Anterior Articulations of the Ribs. The surface of each pit in the side of the sternum is covered by a thin cartilaginous plate, to receive the corresponding car- tilage of the rib, and the articulation presents an anterior and a posterior ligament, also a synovial capsule. The anterior ligament arises from the extremity of the car- tilage, and, going over the front of the sternum, radiates very considerably in every direction. Some of its fibres are con- ARTICULATIONS OF THE THORAX. 281 tinuous with the corresponding fibres of the opposite side; others are lost in the periosteum and in the tendinous origin of the great pectoral muscle; others join the fibres of the ligament above, and of that below. The more superficial the fibres are, the longer they become; but the more deeply seated pass only from the margin of the cartilage to the margin of the cavity in the sternum. The thick ligamentous covering found on the front of the sternum, may be considered as only the continua- tion of these anterior ligaments. The fibres from the two lower articulations on the opposite side, form, by their junction, a striking triangular ligamentous plane, just on the lower end of the second bone of the sternum. Besides which, there are several strong ligamentous fasciculi running in a great variety of direc- tions. The posterior ligament has a similar arrangement with the anterior, in the radiation of its fibres into the contiguous liga- ments, and in their origin from the costal cartilage. Altogether they form, on the posterior face of the sternum, a strong, smooth covering, the fibres of which do not run in fasciculi, but present a uniform polished membrane, and are closely interwoven with each other. Some of these fibres are longitudinal, and of course, cannot be referred to the posterior ligaments, but are indepen- dent of them. The synovial membrane, though its existence is admitted, is not in a very distinct state. It scarcely gives a polish to the articular surfaces, and has so little looseness in its reflection from the one to the other, as to indicate clearly that but an inconsi- derable motion is admitted in these joints. The synovia is in very small quantity, not abundant enough for satisfactory exa- mination, and its character is rather inferred than proved. The first cartilage is continuous with the sternum, and not separated from it by any joint, except in rare instances. The second car- tilage has its joint with the sternum, separated into two, one above and the other below, by a ligamentous partition resem- bling that at the heads of the ribs. The lower articulations become, successively, more moveable than the upper. Vol. I.—36 282 SKELETON. Besides the attachments mentioned as connecting the carti- lages of the true ribs to the sternum, there is one superadded to* the seventh cartilage, called the Costo-Xiphoid Ligament. It arises from the inferior margin of the seventh cartilage, near the sternum, and going obliquely downwards and inwards, is inserted into the anterior face of the xiphoid cartilage, and has its upper fibres running into the corresponding fibres of its fel- low. It is, of course, placed behind the-rectus abdominis mus- cle, and fills up, in some measure, the angle between the seventh cartilage and the third bone of the sternum. At the surfaces where the sixth and seventh cartilages come into contact by their edges, also the seventh and eighth, a syno- vial membrane exists. A similar articulation is sometimes found between the fifth and sixth, and the eighth and ninth car- tilages, but not uniformly. These synovial membranes are co- vered by strong fibres. It has been already stated that the anterior extremity of each of the three first cartilages of the false ribs is united by liga- mentous fibres to the cartilage above. These ligaments are strong and extensive, and give great solidity to the common margin of the cartilages. The two last cartilages being much smaller than the others, no ligaments pass from them; but they, with their ribs, are held in their position by the intercostal and abdominal muscles. The cartilages adhere very closely to their respective ribs, which receive them into the oblong fossae, at their anterior ex- tremities. The periosteum of the rib is continuous with the perichondrium of the cartilage, and the membrane, which is, in fact, one and the same, adheres very closely to the margins of the articulation; it is also re-enforced by some ligamentous fibres beneath it. No motion whatever is admitted at this arti- culation. ARTICULATIONS OF THE UP*ER EXTREMITIES. 283 CHAPTER VIII. OF THE ARTICULATIONS OF THE UPPER EXTREMITIES. Of the Articulations of the Shoulder. These articulations consist in the junction of the clavicle to the upper part of the sternum, and to the first rib; of the scapula to the clavicle, and of the os humeri to the scapula. 1. Of tfie Sterno-Clavicular Articulation. The uneven triangular face of the internal end of the clavicle, and the concavity of the sternum, at its upper corner, form the surfaces which enter into this articulation. The first is much more extensive than the articular surface of the sternum, pro- jects on every side beyond its margins, and is very prominent in cases of extreme emaciation. The two surfaces are covered by cartilage, of which that on the clavicle is the thickest, and serves to fill up its inequalities; while the one on the sternum is thin and smooth. The joint is invested by a thick fibrous capsule, the anterior portion of which presents a strong fasciculus of fibres, somewhat separated by small interstices. This portion, called by some the radiated ligament, arises from the anterior extremity of the cla- vicle, and, going downwards and inwards, is inserted into the mar- gin of the articular cavity of the sternum. It is placed just be- hind the origin of the sterno-cleido mastoid muscle. The cap- sular ligament is also strengthened on its posterior surface by ad- ditional fibres, not so distinct as the preceding, but obtaining the name of the posterior ligament. Of the Inter-Clavicular Ligament, (Lig. Inter-Claviculare.)— Closely connected with the capsule of the joint, this ligament is placed on the superior end of the sternum, and extends from the internal end of one clavicle to that of the other. It is flat before 284 SKELETON. and behind, thin and narrow, is blended with the contiguous liga- mentous structure of the sternum, and might, with propriety, be considered only an appendage to the capsular ligaments, or a process sent between them. In front it corresponds with the in- teguments, and behind with the sterno-hyoid muscles. Of the Inter-Articular fibro- Cartilage.—When the capsule of the joint is cut open, this is brought into view. It separates the bones completely from each other by its extent, and supplies by its shape the want of correspondence in their articular faces. It is thicker above than below; its centre is thin, and sometimes perforated. Its margins adhere closely to the capsular ligament; it is also fixed by adhesion to the upper posterior margin of the surface of the clavicle, and below to the union of the sternum with the first rib; in consequence of which it has but little mo- tion, and in luxations must be lacerated. Its structure is fibro- cartilaginous. Of the Synovial Membranes.—There are two of these, one on each side of the inter-articular cartilage; in consequence of which, a double cavity exists in this articulation, excepting the cases where the cartilage is perforated. These membranes contain but little synovia: they adhere closely to the adjoining surfaces, and cannot be made very distinct, except in points where there are small interstices in the capsule, when,- by pressing the bones strongly together, they protrude in little vesicles. Of the Costo-Clavicular Articulation.—It consists in a short fasciculus of ligamentous fibres, frequently called the Rhomboid Ligament, which, arising from the upper surface of the cartilage of the first rib, ascends obliquely outwards, and is implanted into the roughness on the inferior face of the clavicle, near its sternal end. Its fibres are parallel, all oblique, and longer at its external than at its internal margin. It corresponds in front to the origin of the subclavius muscle, and behind to the subclavian vein. It has for its object the strengthening of the junction of the clavicle with the sternum. ARTICULATIONS OF THE UPPER EXTREMITIES. 285 2. Of the Scapulo-Clavicular Articulations. These exist at three places: the first by a junction between the acromion scapulae and the external end of the clavicle; and the two last by ligaments sent from the coracoid process to the under surface of the clavicle. The Acromio-Clavicular Articulation presents, on each bone, a small oblong face, covered with cartilage. The fibrous capsule which invests it is very strong and thick, so as to give the ap- pearance of a much greater extent to the articular faces of the bones than really exists. This capsule is strengthened by addi- tional fibres on its upper surface, passing from one bone to the other, and sometimes called the superior ligament: they are pa- rallel to each other, and somewhat blended with the tendinous fibres of the deltoid and trapezius muscles. The capsule is also strengthened on its lower face, by additional fibres, constituting the inferior ligament; they are not so abundant as the superior, and pass from the margin of one bone to that of the other, after the same manner. A synovial membrane is reflected over these articular surfaces, and contains but a very small quantity of fluid. In some instances, an inter-articular fibro-cartilage is found in this joint; as in the sterno-clavicular; in such case there is a double synovial membrane. Of the Coraco-Clavicidar Ligament.—This ligament is double, one part being called the Conoid (Lig. Conoides,) and the other, the Trapezoid (Lig. Trapezoides.) It arises from the roughness at the root of the coracoid process, and is attached to the under surface of the clavicle. The conoidal portion, having its base upwards, is inserted into the tubercle, near the external end of the clavicle. Its fibres are compact, strong, and diverging. The trapezoid is placed at the acromial side of the other. It is qua- drilateral, longer, broader and thinner than the other, having its fibres separated by small interstices; and arising also from the root of the coracoid process, it is inserted into' an oblique line leading from the tubercle of the clavicle to its acromial end. The union of these two portions behind forms a projecting angle: 286 SKELETON. in front, there is a depression between them filled with fat and cellular substance, also a bursa mucosa. These ligaments are bounded in front by the subclavius, and behind by the trapezius muscle. The Bifid Ligament (Ligamentum Bicorne) is placed in front of the" subclavius muscle. It arises from the root of the coracoid process, at the sternal side of the conoid ligament; and proceed- ing with but little elevation, inwards and upwards, increases in breadth and bifurcates. The superior horn is inserted into the under margin of the clavicle, near the rhomboid or costo-clavicular ligament; but the lower one goes to the end of the first rib, un- der the tendon of the subclavius muscle. This ligament is a sort of fascia placed over the subclavius muscle, to bind and strengthen it. Some of the fibres of the superior horn some- times proceed farther, and leaving the clavicle, go with the rhomboid ligament into the cartilage of the first rib.* The Coracoid Ligament (Lig. Coracoideum) stretches across the notch on the superior costa, of the scapula, and converts it into a foramen. It runs from the posterior margin of the notch to the base of the coracoid process, and has some of its fibres blending with the conoid ligament. It consists of a small fasci- culus of fibres, and is of very little consequence, excepting in its relation to the superior scapular vessels and nerves. The Triangular Ligament (Coraco-Acromialis) of the Scapula, as its name implies, extends from the coracoid to the acromion process above the shoulder joint. It arises from nearly the whole superior margin of the coracoid process, in two divisions, separated partially by cellular tissue. Its fibres converge in their progress, by which it becomes thicker, and is inserted into the point of the acromion process, just beneath its junction with the clavicle. This ligament is covered by the deltoid muscle and the clavicle, and has the supra-spinatus beneath it. Its anterior margin is continuous with a condensed cellular membrane beneath the deltoid. * Caldani, Plate XLI. ARTICULATIONS OF THE UPPER EXTREMITIES. 287 Of the Scapulo-Humeral Articulation. The glenoid cavity of the scapula, and the head of the os humeri form this joint. As usual, each articular surface is covered with cartilage, of which that on the os humeri is thicker in the middle than near its circumference, while the reverse oc- curs on the scapula. From the shallowness of the glenoid cavity and the much greater size of the head of the os humeri, but very few points of their opposed surfaces can come into contact at the same moment, though they may all do so in succession: hence, a considerable portion of the head of the humerus is always against the capsule of the joint. The remaining parts of this articulation are the capsular ligament, the synovial membrane, and the glenoid ligament. The capsular ligament invests completely this joint, though it is thinner in some places than at others. It arises from the mar- gin of the glenoid cavity, and is inserted into the neck of the os humeri, including a larger space of the neck below, than it does above. The tendons of the muscles which arise from the external * and internal surface of the scapula, to be inserted.into the tube- rosities of the os humeri, as they approach their points of inser- tion adhere very closely to the capsular ligament, and are, indeed, more or less blended with it. Bichat considers, that the tendon of the sub-scapularis muscle supplies the place of the capsular li- gament entirely at its lower part. This ligament is formed by fibres, which are very much intermixed with one another, and have a greater degree of thickness above than below, or, indeed, at any other point. The former is due to a thick fasciculus, the Coraco-Humeral Ligament, also called by some Ligamentum Adscititium, which takes its origin from the posterior and ex- ternal margin of the coracoid process, and proceeding beneath the triangular ligament to the upper part of the os humeri, joins the capsular ligament and adheres very firmly to it. This liga- ment keeps the head of the os humeri on its proper level in regard to the glenoid cavity; but the moment it is cut, the length of the capsular ligament permits the head of the os humeri to fall about an inch, and, indeed, to suffer a partial dislocation. The strength 288 SKELETON. of the joint, however, depends essentially upon the muscles which surround it, as the deltoid, supra-spinatus, infra-spinatus, teres minor, sub-scapularis, long head of triceps, and some others, which are farther removed from it. The synovial membrane is a perfect sac, which covers the glenoid cavity, the internal face of the capsular ligament, and the neck and head of the os humeri. On the lower part of the neck it is reflected over some small fatty masses, commonly called glands. Just beneath the root of the coracoid process, from their being a deficiency of the capsular ligament, the synovial mem- brane covers the articular side of the tendon of the sub-scapularis, and is reflected for ten or twelve lines, between it and the sca- pula, forming a sort of pouch, resembling a bursa mucosa. The tendon of the biceps muscle runs through this articulation from the superior end of the glenoid cavity. The cavity itself is deepened by a fibrous margin all around, called the glenoid liga- ment; a considerable part of whose fibres may be traced from the tendon of the biceps by its bifurcating. The tendon is bound down in the bicipital groove by fibres passing from one to the other of the bony margins, and which may be considered a con- tinuation of the capsular ligament. As the tendon is about emerging from the groove at the lower margin of the tuberosi- ties, the synovial membrane which lines the groove thus far, is reflected from it, to the surface of the tendon, and continues to cover and enclose it up to the origin at the glenoid cavity. It is thus evident that though the tendon passes through the joint, the cavity of the synovial membrane is kept entire. Of the Elbow Joint. This articulation is formed by the lower end of the os humeri and the upper end of the ulna and of the radius. The articular faces which were described in the account of these bones are co- vered, as usual, with cartilage, the particular arrangement of which will be presently pointed out. A strong capsular ligament, an annular or coronary ligament, and a synovial membrane, hold these several bones together. ARTICULATIONS OF THE UPPER EXTREMITIES. 289 The Capsular Ligament invests completely the articular ex- tremities of these bones, and conceals them from view. It is at- tached to the sides of the os humeri at the lower part of its con- dyles near the articular surface; but in front it arises some dis- tance from the articular face at the upper margins of the little cavities, for the head of the radius and the coronoid process of the ulna: behind, it arises in like manner from the upper margin of the cavity for receiving the olecranon process; so that the de- pressions, both before and behind, are included within the circum- ference of the articulation. The lower part of the capsular li- gament is inserted into the margin of the articular surface of the ulna, all around, including, also, the whole of the head of the ra- dius, and the upper part of its neck. This capsule is strengthened very much at particular points, and as the joint is hinge-like, the strengthening is more abundant at its sides, constituting lateral ligaments. The External Lateral, or the Brachio Radial Ligament, (Lig. Cubiti Externum,) is connected above to the lower part of the external condyle, and is fixed below into the annular ligament which surrounds the neck of the radius. It is very much con- founded with the tendinous mass common to the muscles at this part of the arm, more particularly that of the supinator radii brevis. It is a round fasciculus of parallel and condensed fibres, spreading somewhat below into the annular or orbicular ligament. The Internal Lateral or the Brachio Ulnar Ligament (Lig. Cu- biti Internum) arises from the lower part of the internal condyle, and spreading out so as to assume a triangular shape, divides into two portions, one of which is inserted into the internal margin of the coronoid process of the ulna, and the other into the internal margin of the olecranon process. It also is much blended with the tendons of the muscles which lie over it. Intermediately to the lateral ligaments, both before and behind, the fibrous struc- ture of the capsular ligament is very distinct, but thin, in order to accommodate the motions of the joint; some of the fibres are insulated, and have interstices between them filled with fat. Some of these fibres are oblique, and others straight: they are called, generally, accessory ligaments. Vol. I.—37 290 SKELETON. The Coronary Ligament of the Radius (Lig. Radii Orbiculare) is brought more distinctly into view by cutting open the joint. It is then seen to arise from the anterior margin of the lesser sigmoid cavity of the ulna, and surrounding two-thirds of the neck of the radius, to be inserted into the posterior margin of the same cavity. It is a strong, flat, narrow fasciculus, the fibres of which go in a circular direction. Its superior margin is blended with the external lateral ligament; its inferior margin is loose, being connected with the lower part of the neck of the radius only by a reflection of the synovial membrane, with the excep- tion that a few fibres pass from it behind, to the contiguous part of the ulna. Its density is very considerable, sometimes almost cartilaginous. The Synovial Membrane lines the whole internal face of the capsular ligament, from which it is separated behind by a large mass of fat in the olecranon depression of the os humeri, and in front by another mass in the coronoid depression. A small cir- cular ridge of fat also projects into the joint around the head of the radius, and there is another at the internal margin of the olecranon. The object of these masses seems to be to fill up the partial vacancies which exist between the articular faces of the bones, and they are all so managed by their attachment to the capsular ligament, as to be preserved from being pinched. The synovial membrane is also reflected from the capsular ligament to the articular faces of the bones, so as to line the several de- pressions on the os humeri, and to include the neck of the ra- dius. The head of the radius is completely invested with cartilage. The greater sigmoid cavity of the ulna has the cartilage sepa- rated transversely into two portions, by a small mass of fat tra- versing its bottom. The cartilage elsewhere is uniformly spread over the articular surfaces of the bones. Of the Interosseal Ligament, (Membrana Interossea.)—It fills up the space between the two bones of the fore arm almost entirely, by commencing just below the tubercle of the radius and ending near the wrist. It consists in oblique and parallel fibres, which ARTICULATIONS OF THE UPPER EXTREMITIES. 291 pass from the ulnar edge of the radius downwards to the radial edge of the ulna. It is thin, but extremely strong, being covered in front by the flexor muscles; and behind by the extensors, and, as Mr. Boyer observes, seems to be intended rather to afford ori- gin to muscles than to unite the bones. Its superior part is thin- ner above, and a large opening exists there for the passing of the interosseal vessels to the back of the fore arm. Its inferior part is thicker, where openings also exist, but small, for the passing of vessels. There are some other smaller perforations in this liga- ment, but of less note than the preceding, also for vessels. On its posterior face there are one or two bands, the fibres of which decussate the other fibres. Beside the interosseal ligament, there is one called round, si- tuated obliquely between the two bones at the upper part of the interval which separates them. It arises from the base of the coronoid process, just below the insertion of the brachialis inter- nus ; and descending obliquely outwards, is inserted into the ra- dius below its tubercle. Its object is to bind the bones together, at a point which is weakened by the deficiency of the interosseal ligament. This deficiency is, in fact, much larger than the sim- ple passing of the vessels requires; for it is also large enough to allow the tubercle of the radius to rotate freely, a motion which would have been checked by the presence of the ligament. Of the Articulations of the Wrist. Several articular cavities present themselves at this point. One is between the lower part of the ulna and the radius, an- other between the carpal bones and those of the fore arm, and a third between the two rows of carpal bones. One general cap- sule invests these parts. 1. The Lower Radio-Ulnar Articulation—is surrounded by a section of the fibres belonging to the general capsular ligament of the wrist: their attachment, however, is so loose, that they al- low the bones to rotate freely upon each other, besides which they are not so abundant as in other places. When this joint is cut open, it will be seen that the head of the ulna is covered 292 SKELETON. with cartilage, and that the cartilage which covers the carpal articular face of the radius, projects between the ulna and the os cuneiforme; and covers also the sigmoid cavity of the radius; so that a cavity for receiving the convex head of the ulna is formed by the cartilage of the radius. The margins of this pro- jecting point of the radial cartilage are fibrous, which has in- duced the French anatomists to speak of it under the name of triangular ligament. It is, in fact, an mter-articular fibro-carti- lage, and is said to be. occasionally detached from the radius, but I have not seen it in that state: its centre not unfrequently is perforated, so that a communication exists between this joint and the next of the wrist. Its margins adhere very closely to the capsular ligament, and its point is fixed into the depression which separates the styloid process of the ulna from its head. The synovial membrane which lines this cavity is unusually loose, both before and behind, in consequence of the great motion of the bones: it is also very loose above. This joint is sometimes called the Sacciform, from its looseness. 2. Of the Radio-Carpal Articulation.—The radius above, and the scaphoides, lunare, and cuneiforme below, form the basis of this articulation. An oblong, elliptical cavity, the ulnar extre- mity of which is made by the projection of the cartilage of the radius, receives the convexity of the bones of the wrist. The scaphoides and the lunare come in contact with the radius, while the cuneiforme rests against the projecting cartilage. There is a slight elevation of the radial cartilage opposite to the interstice between the two first bones. The oblong elliptical cavity is filled by a corresponding head, on the part of the bones of the carpus just enumerated. Each of the latter bones, in a fresh state, is covered by its appropriate cartilage. The cartilages are connected, or rather continued into one another, by a nar- row fibro-cartilaginous substance placed at the margin of the in- terstice between these bones. This substance separates the ca- vity of the radio-carpal articulation from that of the proper carpal articulation. The Capsular Ligament arises, before and behind, around the margin of the particular face of the bones of the fore arm, from ARTICULATIONS OF THE UPPER EXTREMITIES. 293 the styloid process of the radius to that of the ulna, adhering very closely to the margins of the fibro-cartilage insinuated be- tween fhe ulna and the cuneiforme. It is inserted below, into the circumference of the head formed by the scaphoides, lunare, and cuneiforme, though many of its fibres may be traced to the bones of the second row. It is a loose and thin membrane, the fibrous fasciculi of which leave interstices at several points be- tween them, through which the synovial membrane may be seen. The capsular ligament is strengthened at particular places, by additional fasciculi of fibres having appropriate names. For ex- ample, the internal lateral ligament arises from the styloid process of the ulna, and is inserted into the cuneiforme, some of its fibres being extended to the anterior annular ligament, and to the pisi- forme. The external lateral ligament arises from the styloid process of the radius, and is inserted into the radial end of the scaphoides; some of its fibres being continued on to the trapezium, and to the anterior annular ligament. The anterior ligament arises from the vicinity of the styloid process of the radius, and passing obliquely downwards and inwards, is inserted into the anterior face of the scaphoides, lunare, and cuneiforme. Its fibres are not very evident or well marked. The posterior liga- ment is not so broad as the last, and is more distinct. It also arises from the radius, by and near its styloid process, and de- scending obliquely inwards, is inserted into the lunare and cunei- forme. The two last ligaments have no connexion with the ulna, the rotation of the fore arm is, therefore, unimpeded by them. The synovial membrane of the radio-carpal articulation is dis- played on the articular faces of the bones and their intermediate fibro-cartilage, and lines the internal face of the capsular liga- ment. When the joint is pressed upon, this membrane is pro- truded, in the form of little vesicles, in the interstices between the fasciculi of the capsular ligament. A fold of it containing a small quantity of adipose matter is observed on the back of the cavity of the joint, passing from the junction of the scaphoides and lunare to the corresponding point of the radius; it is the liga- mentum mucosum of some writers. 294 SKELETON. 3. Of the Articulation between the two rows of the Carpal Bones. —The scaphoides, lunare, and cuneiforme of the first row, and all the bones of the second row, are the foundation of this joint, the surfaces of which have been described already. These sur- faces are covered with cartilage, each bone having its appro- priate cartilage, which is continued on its side where the bone touches the adjacent one. The joint is furnished with a capsu- lar ligament and a synovial membrane. The Capsular Ligament surrounds the articulation, passing on every side from the upper to the lower row, and adhering strong- ly to the bones. It is in a great degree a continuation of the capsule of the radio-carpal joint, and has, at the same points, an increase of thickness, called after the same names. The internal lateral ligament is attached by one end to the cuneiforme, and by the other to the side of the unciforme. The external lateral ligament arises from the extremity of the scaphoides, and is in- serted into the side of the trapezium. The posterior and ante- rior ligaments have the course of their fibres more distinctly seen on the side of the synovial membrane. The first consists in many fibres arising from the bones of the first row and going to the second row; its fibres are shorter and more compact. The anterior arises and is inserted after the same way, some of them terminating in the anterior ligaments of the hand. The Synovia] Membrane is not only displayed on the opposite surfaces of the two carpal rows, but also is reflected upon the lateral faces of the bones belonging to each row. It, therefore, sends processes, two of which are found, above; one between the scaphoides and the lunare, and the other between the lunare and cuneiforme. These processes are arrested at their upper extremities by the fibro-cartilaginous matter between the bones, which was spoken of in the radio-carpal articulation. It also sends three processes downwards, one between the trapezium and the trapezoides, another between the latter and the magnum, and the third between the magnum and the unciforme. Those latter processes communicate with or are continuous with the synovial membrane, between the carpal and metacarpal bones ARTICULATIONS OF THE UPPER EXTREMITIES. 295 of the fingers.* The connexions and reflections of this mem- brane are of the greatest importance, as they form a communi- cation from the top of the wrist to the base of the metacarpal bones; not only covering the articular surfaces, but being pro- longed in some instances beyond them, as on the back of the neck of the os magnum, where it answers as a periosteum. In addition to the articulation just described, between the two rows of carpal bones, the individual bones of each row have particular fastenings of ligamentous fibres, which run transverse- ly from the margin of one bone to the margin of the next. These fibres, from their position, are called dorsal and palmar ligaments. The upper row has one dorsal ligament between the scaphoid and lunar, and another between the latter and the cu- neiform—it has in the same way two palmar ligaments on its front surface. The lower row has, after the same plan, three dorsal and three palmar ligaments between its bones. These se- veral ligaments are best seen on the side of the synovial mem- brane, as externally their fibres are very much mixed with those of the capsular ligament. It is obvious that they are highly useful in preventing the bones from sliding laterally on each other, except to a small extent. The Pisiform Bone has an articulation with the cuneiform com- pletely distinct from any other. The articular faces of this joint are covered with cartilage and invested by a synovial membrane and a capsular ligament, which allow, from their looseness, con- siderable motion. The Capsule, though generally thin, is strength- ened by accessary fibres, which are well marked below. These fibres arising from the inferior extremity of the pisiform, some of them are attached to the extremity of the unciform process of the os unciforme, and others to the base of the fifth metacarpal bone. The insertion of the tendon of the flexor carpi ulnaris an- swers as a-ligament to this bone above. It has but little motion from above downwards, and a good deal laterally. Of the Carpo-Metacarpal Articulations. The bony articular surfaces, here, as well as all the others of the hand, have been sufficiently described, and are in the recent * Bichat, Anat. Descr. 296 SKELETON. state covered with cartilage. It will therefore be unnecessary to renew the observations on these subjects. The first of these articulations, or that of the metacarpal bone of the thumb, with the trapezium, is much more moveable than any of the others, and presents some peculiarities. It is entirely distinct, slightly removed from the next, and is surrounded by a capsule which is attached by its ends to the articular margins of the bones. This capsule is strengthened by additional fibres, which are particularly distinct and abundant, posteriorly and ex- ternally. The synovial membrane is displayed, as usual, on the internal face of the capsule and over the articular faces. The other four metacarpal bones are articulated as follows: The second one is joined to the trapezoides, trapezium, and mag- num—the third unites to the magnum alone—the fourth to the unciform, with a small portion of the magnum—and the fifth to the unciform. The ligaments are placed before and behind, and may also be termed dorsal and palmar. The dorsal ligaments descend from the carpal to the metacar- pal bones. The second metacarpal bone receives two ligaments, one from the trapezium, and another from the trapezoides—the third receives one from the magnum—the fourth receives two, one from the magnum, and the other from the unciform—the fifth receives one from the unciform. Transverse fibres pass between these dorsal ligaments to the bones. The palmar ligaments are arranged on a plan corresponding with that of the dorsal; but, from the length of their superficial fibres, are not so distinct from each other. Transverse fibres pass also between the metacarpal bones of the fingers at their base, and form interosseous ligaments which keep them together. The articulations thus formed and held together, are covered by two synovial membranes, being processes from that between the two rows of carpal.bones. One of these processes, sent down between the trapezoides and the magnum, displays itself over the inferior surface of these bones and the head of the metacar- pal bone of the fore and of the middle finger. The second pro- cess which is sent down between the magnum and the unciforme, is reflected over the two last carpo-metacarpal articulations. ARTICULATIONS OF THE UPPER EXTREMITIES. 297 These processes have a septum between them, at the ulnar side of the base of the third metacarpal bone, and do not communi- cate with each other, except through the proper carpal articu- lation. The specification of this arrangement is overlooked by anatomists generally. The Inferior Palmar Ligaments are three in number, and are between the lower ends of the metacarpal bones of the fingers, each one consists in a transverse fasciculus, placed between the flexor tendons and the interosseous muscles, and on a level with the anterior part of the first joint of the fingers. Their more su- perficial fibres may be traced across the bones, and are some- what blended with the capsular ligaments; the more deep-seated are short, and pass from one bone to the other. Of the Metacarpo-Phalangial Articulations, These are formed by the lower ends of the metacarpal bones* and the upper ends of the first phalanges. Each one presents an anterior ligament, two lateral ones, and a synovial mem- brane. The anterior Ligament* is a flat fibrous semicircle, on the front of the articulation, of considerable thickness. It goes trans- versely, and has its two extremities attached to the ridge on either side of the articular margin of the metacarpal bone. Its inferior margin descends a little, and comes in contact with the synovial membrane. In front, many of its fibres are obtained from the ligamento-cartilaginous sheaths of the flexor tendons, so that it may be considered as made by two planes—the palmar one facing towards the tendons, and forming the trochlea, in which they play, and the other being next to the joint, and continued to the lateral ligaments. The thickness of the anterior ligament, be- sides communicating great strength to the joint, is useful in re- moving the tendons from the line of motion of the phalanges, and thereby giving increased power and delicacy of motion to the muscles. Bichat considers himself to have first indicated parti- cularly this structure, which he thought was intended to protect * Bichat, loc. cit. Vol. I.—38 298 SKELETON. the articulation from the impression of the tendon: he ought to have added, in the firm grasping of bodies, and to make the move- ments of the joint more delicate. On the sides of this ligament, belonging to the thumb, and in its thickness, are developed the sesamoid bones. The Lateral Ligaments are situated one on each side. They arise from the sides of the metacarpal bone behind the former, and in connexion with it, and, descending obliquely forwards, are fixed into the sides of the upper end of the first phalanx. They are round, distinct, and strong, and are formed from numerous parallel fibres. The Synovial Membrane lines this articulation, being displayed over its lateral and anterior ligaments, and on the articular faces of the bones. It is reflected on the metacarpal bone, some little distance from the margin of its cartilage in front, whereby the cavity is enlarged, and the flexion of the fingers is favoured. It is in contact, behind, with the tendon of the extensor muscle, which there supplies the place of ligament. Of the Phalangial Articulations. There are two of these to each finger, and one only to the thumb. They are provided with an anterior ligament, a lateral ligament on each side, and a synovial membrane. The Anterior Ligament corresponds so exactly with what has been said in the preceding article on the same structure, that, with the exception of its being smaller, the description, already given, will suffice. It seems to answer, in every respect, the same objects. ■# The Lateral Ligaments, also, arising from the sides of the pha- lanx above, run downwards and somewhat forwards, to be insert- ed into the upper part of the sides of the phalanx below. The Synovial Membrane has reflections corresponding with those of the preceding articulations, with the addition that it co- ARTICULATIONS OF THE UPPER EXTREMITIES. 299 vers more of the anterior inferior face of the first and second pha- langes. Thus, by cutting through the anterior ligament, longitu- dinally, and turning it aside, it will be seen that the cavity of the second and third joints of the finger is, by this reflection of the synovial membrane, extended upwards between the phalanx and the flexor tendons nearly one-third of the whole length of the phalanx,* a circumstance worth attending to in the accidents of the part. CHAPTER IX. OF THE ARTICULATIONS OF THE LOWER EXTREMITIES. Of the Ilio-Femoral, or Hip Articulation. The basis of this articulation is laid by the head of the os fe- moris being received into the acetabulum. Both surfaces are covered by thick cartilage: in the former it is interrupted, how- ever, by the depression near the centre, and becomes very thin near the margin; and, in the latter, the cartilage is deficient in the whole extent of the rough surface at its lower part. A coty- loid ligament, a fibrous capsule, the round or inter-articular liga- ment, and a synovial membrane, are, moreover, concerned in this joint. The Cotyloid Ligament (Lig. Cotyloideum) is a fibrous prismatic ring which tips the margin of the acetabulum, and thereby in- creases its depth; it can only be seen by cutting open the cap- sule. Its thickness is unequal, being considerable on the anterior third of the circumference of the acetabulum, where it assiStHn converting the notch into a foramen, but not so much so elsewhere. Just below the anterior inferior spinous process, the acetabular head of the rectus femoris sends some tendinous fibres to it. Its base is broader than its margin, and is marked off from the ar- ticular cartilage by a line, or narrow groove, between them. Its * Bichat, loc. cit. 300 SKELETON. acetabular side is covered by the synovial membrane; the other side has the capsular ligament adhering to it; and the third side adheres to the bone. Where it subtends the notch of the aceta- bulum, the cotyloid ligament is re-enforced by additional liga- mentous fibres, placed beneath it, and going from the upper to the lower end of the notch. These fibres consist of two planes, one internal and the other external, partly crossing each other, and adhering closely to the cotyloid ligament. The Inter-Articular, or Round Ligament, (Lig. Teres,) is a true ligamentous band, which is attached at the one end to the pit on the head of the os femoris, and afterwards by a slight dis- section, is easily separated into two fasciculi. Of these, the lower one may be traced to the inferior end of the cotyloid notch, where, winding around the prominence of bone, it begins to ad- here to the ischium, and continues to do so from that point along the anterior face of the ischium, just below the acetabulum, to a point between the latter and the upper anterior part of the tuber. The other portion is directed towards the superior end of the notch, and is attached there by two extremities, one near the margin of the acetabulum, and the other three or four lines from it within.* The fibres of the round ligament are somewhat in- termixed also with those of the ligament subtending the notch. The Capsular Ligament (Capsula Fibrosa) is the strongest in the body, and represents a conoidal sac, open at both extremities, by which it adheres to the bones. It is fixed by its base to the circumference of the acetabulum, beyond the cotyloid ligament, and to this ligament itself, where the latter subtends the notch. It embraces that part of the head of the os femoris which pro- jects above the margin of the acetabulum, and descends along the neck to its root. It is longer in front; is fixed there to the oblique line which runs between the two trochanters, and, be- hind, into the root of the neck, a little in advance of the posterior oblique ridge, and in such a manner as to leave a small part of the neck of the os femoris bare below it. Above, it is fixed to the neck, just below the rough fossa in the trochanter major; and on the under surface of the neck it adheres, just above the * Antonius et Caldani, Tabula II. ARTICULATIONS OF THE LOWER EXTREMITIES. 301 trochanter minor. It is strengthened in several places by pro- cesses from the fascia lata femoris, which descend to it between the muscles surrounding the hip joint.* Its thickness is consider- able, but variable. In front, and above, it is remarkably strong, where it is re-enforced by a large fasciculus of fibres coming from the anterior inferior spinous process of the ilium, and descending, longitudinally, to the anterior oblique ridge of the os femoris. The internal and posterior portions of the orbicular or capsular ligament are not so thick; it is, indeed, frequently very thin near the posterior ridge of the os femoris, and has a number of holes in it for the passage of vessels. It is strengthened, internally, by some fibres coming from the superior margin of the thyroid fora- men. This ligament keeps the bones closely applied to each other, and is by no means so loose as the corresponding one of the shoulder joint. Its fibres are very irregular, generally, in their course, and difficult to follow. The strength of this articulation depends principally on the muscles which surround it, of which the rectus femoris, and the iliacus internus and psoas magnus united, are in front; between the latter two and the capsule, is a bursa mucosa. Within, are the pectineus and the obturator externus; behind, are the quad- ratus, the gemini, the obturator internus, and the pyramidalis; above and behind, are the glutei, t The Synovial Membrane is a complete sac, displayed over the articular surfaces of the bones, and the internal face of the cap- sule. It is separated from the roughness at the bottom of the acetabulum, by the existence there of a pad of very vascular, * Soemmering", De Corp. Hum. Fabrica, vol. ii. p. 61, 1794. Andrew Fyfe, Compendium of Anat. Philad. 1807, vol. i. p. 179. ■f For an interesting account of the connexion of this capsule with the fascia femoris, see Anatomical Investigations, by J. D. Godman, M. D., Philad. 1824. The author, in following the sheaths of the muscles, or, in other words, the pro- cesses of the fascia lata, between the muscles, to the capsule, with great attention, has been brought to the conclusion that the capsule is formed entirely from them. He has presented the same views in regard to the shoulder joint, and others. Though not disposed to concur in so general an inference on the source of cap- sular ligaments, inasmuch as their peculiar texture is opposed to it, and many other circumstances in their anatomical arrangement, I have yet to express great satis- faction in the fidelity with which these connexions of the larger joints have been traced. 302 SKELETON. fine, fatty matter, from which, according to Bichat, it may be raised by blowing beneath the ligament of the notch, at the point where the blood vessels enter. Coming from the acetabulum, it covers the articular face of the cotyloid ligament, and is then re- flected to the capsule, to which it gives a polished internal face, and from which it may be dissected. On reaching the root of the neck of the os femoris, it forms small duplicatures, and is re- flected upwards along the neck to the head, being separated from the neck by periosteum, or by a fibrous tissue, which M. Boyer considers a continuation of the capsule. It covers all the head, except the point of attachment for the round ligament, and to the latter it gives a sheath, which, at the other end, is con- tinuous with the part of the synovial membrane covering the fatty matter. From the latter circumstance, arises a deceptive appearance of the round ligament being inserted into the rough- ness in the bottom of the acetabulum. Of the Knee Joint. It is formed by the os femoris, the tibia, and the patella, the particular modelling of whose surfaces, for the purpose, has been described. These surfaces are all covered by a uniform lamina of cartilage, and are held together by an apparatus which for the number of its parts and their arrangement, makes this the most composite joint in the skeleton. The most superficial layer of the knee joint is the fascia lata of the lower extremity, which, in passing down from the thigh to the leg, is so near the cavity of the articulation on each side of the tendon of the patella, that it is by Weitbrecht spoken of under the term of Common Investment (Involucrum Generate.) It is here not only a continuation of the fascia femoris, but this fascia is increased and thickened by an aponeurosis, which springs from the inferior extremity of the extensor muscles on the thigh. The membrane thus formed covers both the patella and its liga- ment, and extends on each side to the lateral ligaments of the joint, to which it adheres; it may be traced even behind them, but there it becomes indistinct, loose, and blended with common cellular and adipose membrane. The involucrum adheres strongly to the internal and external condyles, and to the head of the ARTICULATIONS OF THE LOWER EXTREMITIES. 303 tibia; it has oblique fibres on the patella, transverse ones on the ligament of the latter, and longitudinal ones on each side. It is in contact with the synovial membrane of the joint, except in the middle portion, where it is separated from it by the patella, and its tendon, and some adipose matter. It may be dissected without difficulty from the subjacent parts, by which the liga- ment of the patella, and the synovial membrane are brought into view. The Ligament of the Patella being situated at the fore part of the articulation, though separated from the extensor muscles by the intervention of the patella, is nevertheless, their tendinous insertion into the leg. It arises from the whole inferior margin of the patella, and is inserted into the tubercle of the tibia. It consists in longitudinal, closely compacted fibres, of a character entirely tendinous; the more superficial of them give a layer to the front of the patella, and in the fracture of the latter some- times prevent a separation of its fragments. In front, as just mentioned, it is in contact with the involucrum generale; behind, is a large mass of fat placed between it and the synovial mem- brane of the joint; and on the same surface, but lower down, it is in contact with a bursa mucosa fixed between it and the tri- angular flatness of the tibia above the tubercle. A posterior ligament, an internal and an external lateral liga- ment, two crucial ligaments, two semi-lunar cartilages, and a synovial membrane, compose the remaining apparatus of the joint. The Posterior Ligament (Lig. Posticum,) is a fibrous expansion? on the back of the knee joint, which may be considered as the proper capsular ligament at this point, and has its fibres extend- ing obliquely from the external condyle of the os femoris to the posterior part of the head of the tibia. It is frequently called the ligament of Winslow, and by the French anatomists is considered as one of the divisions of the tendinous insertion of the semi-mem- branosus muscle, in consequence of its close connexion with it. There are several foramina or interstices in it, which permit a passage of blood vessels to the fatty matter placed between it 304 SKELETON. and the crucial ligaments; and beneath it there are some trans- verse fibres. The Internal Lateral Ligament (Lig. Laterale Internum) is a flattened fasciculus of fibres placed at the internal side of the joint. It arises from the tuberosity on the inner side of the in- ternal condyle, and descending vertically is slightly attached to the semi-lunar cartilage, and is then inserted into the superior margin and the internal face of the head of the tibia for two inches or more, increasing in breadth as it descends. On the one side it is in contact with the synovial membrane, and on the other, with the involucrum and the tendons of the sartorius, the semi- tendinosus, and the gracilis. The External Lateral Ligament (Lig. Laterale Externum Longum,) placed on the external side of the joint, is nearer its posterior face than the internal ligament. It arises from the tuberosity on the outer face of the external condyle, above and behind the tendinous origin of the popliteus muscle, and is inserted into the external part of the superior extremity of the fibula, be- ing covered in almost its whole extent by the tendon of the biceps. Its inner face is in contact with the synovial membrane, and the articular vessels. Its rounded form and shining appearance make it look very much like a tendon. Behind it, is a smaller fascicu- lus, called by some the short external lateral ligament, which passes from the external condyle to the head of the tibia. The Crucial Ligaments (Lig. Cruciata,) two in number, are named from their crossing one another laterally, and thereby forming a figure, resembling the letter X, or a Malta cross. They are situated at the posterior part of the articulation be- tween the posterior ligament and the synovial membrane. One of them is called anterior, and the other posterior, from their re- lative situation to each other. The first arises from the internal face of the external condyle, by a depression near the bottom of the notch and just at the margin of the articular surface; it de- scends forwards, and is inserted immediately in front of the little ridge between the articular faces of the tibia. The second arises from the bottom of the notch between the condyles, just behind ARTICULATIONS OF THE LOWER EXTREMITIES. 305 the trochlea for the patella, upon a surface that may be con- sidered as belonging to the internal condyle; it descends back- wards, and is inserted into the rough surface behind the afore- said spine or ridge of the tibia. The crucial ligaments are large, round, and composed of parallel fibres very closely compacted; their strength is very considerable, and they serve not only to limit the extension of the leg, but also to check any thing like rotation inwards. The Semilunar Cartilages (Gartilagines Semilunares, falcate,) are two in number; one placed on each side of the superior face of the tibia, between it and the condyles of the os femoris. Their shape is sufficiently indicated by their names, and as they are placed on the circumference of each articular surface of the tibia, leaving the middle uncovered, they increase considerably the depth of the concavities for receiving the condyles. Their external circumference is thick, whereas, the internal is reduced by a gradual diminution of their thickness, to a very thin edge. The internal cartilage is but little more than a semicircle, and is longer in its antero-posterior diameter than in its transverse: on the other hand, the external is almost circular; an arrange- ment by which each is suited to its respective surface. They adhere by their greater circumferences to the fibrous matter surrounding the joint, particularly the lateral ligaments, but not so closely as to prevent their sliding backwards and forwards in the flexions of the leg. The tendon of the popliteus adheres to the external, either directly or by the intervention of a small synovial sac. The internal semilunar cartilage is attached by its fore ex- tremity to the anterior internal side of the roughness in front of the ridge, called spinous process, on the top of the tibia, and by the hind extremity to the posterior face of the base of the ridge, just in advance of the posterior crucial ligament. The external cartilage is attached by its anterior end, also, to the roughness in front of the ridge; but this attachment is considerably behind the corresponding one of the internal cartilage, and is somewhat blended with the anterior crucial ligament: the posterior end is fixed into the depression on the summit of the ridge or spinous process, and is there between the two crucial ligaments. The anterior extremities of the two cartilages are united by a trans- Vol. I.—39 306 SKELETON. verse ligamentous fasiculus a line in thickness, which is rather inconstant; but when found, is in front of the anterior crucial ligament. These bodies, though presenting an appearance cor- responding with cartilages, on their surface, are, nevertheless, formed principally from concentric ligamentous fibres; the cha- racter of which is very evident at their extremities, and when they are lacerated. The Synovial Membrane is thin, loose, and delicate, and, as in other joints^ is a perfect bag, covering the articular faces of the bones, and reflected from the one to the other. As there is no regular capsular ligament to the knee joint, the synovial membrane is very distinct on each side of the tendon of the pa- tella ; and comes in contact there with the fascia lata, or involu- crum, as it passes from the thigh to the leg. The synovial mem- brane, after covering the articular faces of the tibia, is reflected from their margin upon the semilunar cartilages so as to invest their inferior and superior surfaces; it then ascends to the con- dyles of the os femoris. It covers the condyles, laterally, as well as on their articular faces, and leaves thereby half an inch or more of their circumference on each side of the trochlea of the patella, included in the periphery of the joint. The synovial membrane, anteriorly, being separated from the tendon of the patella, by the large mass of fat, then covers the posterior face of the patella, and, rising up still farther, lines the posterior face of the tendons of the extensor muscles for the distance of three inches or thereabouts. The superior end of this reflection is formed into a small pouch, communicating freely with the gene- ral cavity, but marked off from it by a partial and variable sep- tum on each side. Some anatomists consider the pouch as a bursa, but it is so seldom seen entirely distinct from the joint, that it answers better to describe it as a part only of the gene- ral reflection. The synovial membrane, at the sides of the joint, is in contact with the lateral ligaments. Behind, it is reflected on the anterior surface of the tendinous origins of the gastrocne- mius, and envelops the tendon of the popliteus; it also invests the crucial ligaments, but in such a way as to leave them out of its cavity. The mass of fat behind the tendon of the patella forms, just ARTICULATIONS OF THE LOWER EXTREMITIES. 307 below the latter, a ridge on each side, protruding into the arti- culation, and having a fringed summit formed by a doubling of the synovial membrane. The external ridge is the Ligamentum Alare Minus Externum, and the other the Ligamentum Alare Majus Internum. These ridges converge at their lower extre- mities, and from their point of union proceeds a duplicature of the synovial membrane, in front of the anterior crucial ligament; the other end of the duplicature is attached to the posterior ex- tremity of the groove, in the middle of the trochlea, for the pa- tella. This duplicature is the Mucous Ligament, (Ligamentum Mucosum.) Of the Peroneo-Tibial Articulation. The tibia and fibula are held together by three places of union, one above, another below; and, thirdly, the ligament which fills up the space between the bodies of the bones. 1. The Superior Articulation, formed by the upper extremity of the fibula and the outer side of the head of the tibia, is entire- ly disconnected with the cavity of the knee joint, and has no- thing in common with its apparatus, except the external lateral ligament, which has been described. The articular faces are small, and covered with cartilage; an anterior and a posterior ligament, and a synovial membrane, hold the bones together at this point. The anterior ligament is attached by one end to the front of the head of the fibula, and, proceeding upwards and inwards, is inserted, by the other, into the contiguous part of the head of the tibia, before the articular facet. The fibres are separated into fasciculi, leaving interstices between them for cellular sub- stance. The posterior ligament is narrower than the anterior, but its fibres are more compact; and, like the anterior, they observe a transverse course, being attached by the one end to the head of the fibula, and, by the other, to the head of the tibia. The pop- liteus muscle covers them. This joint is also strengthened by other ligamentous fibres, and by the insertion of the tendon of the biceps. The synovial membrane is reflected over the articular faces 308 SKELETON. and the ligaments described, and has nothing of particular inte- rest in it. Occasionally, the synovial membrane of the knee joint runs into it. 2. The Inferior Articulation, which is formed between the lower extremities of the bones, is not incrusted by cartilage, ex- cept to the breadth of a line at its lower part, bordering on the ankle joint. Its anterior ligament is broad, and covers the face of the bones which are in apposition. Attached by the one side to the front of the lower extremity of the fibula, its fibres pass obliquely up- wards and inwards, to be inserted into the corresponding part of the tibia. Several interstices exist in it for the passage of ves- sels, and it is covered by the peroneus tertius. Its lower margin is in contact with the astragalus, and forms a portion of the ankle joint. The posterior ligament, in the arrangement and course of its fibres, corresponds with the anterior; being attached by one side to the posterior face of the fibula, and by the other to the cor- responding part of the tibia. Like the other, its fibres are longer near the ankle joint than above. Its lower margin is in contact with the astragalus, and is connected with other ligaments coming from the fibula. In the space between the anterior and the posterior ligament, where the bones touch, they are agglutinated by a short, strong, fibrous tissue, leaving intervals occupied by adipose matter. It contributes much to the solidity and immobility of this articula- tion. 3. The interosseous Ligament (Membrana Interossea) is analo- gous to that in the fore arm, by being a membrane stretched between the two bones. It arises from the ridge on the outer face of the tibia, and is attached to the corresponding ridge on the inner face of the fibula. It is broader above than below, being at the latter point continuous with the fibrous structure which agglutinates the bones. Just below the head of the fibula is a large hole for transmitting the anterior tibial vessels, and the origin of the tibialis posticus muscle. It also presents, in its descent, several smaller foramina for the passage of vessels. Its ARTICULATIONS OF THE LOWER EXTREMITIES. 309 fibres are strong and unyielding, and run obliquely downwards from the tibia to the fibula. It is covered in its whole length, both before and behind, by muscles, and serves as an origin to them and as a means of attachment between the bones. Of the Ankle Joint. The articular surfa'ces, here, being covered by cartilage as in other moveable joints, are formed by the astragalus being re- ceived into a deep cavity made by the tibia and the fibula. The capsular ligament, properly speaking, does not exist either on the front or the back of the joint, and is represented, there, by a few scattered, loose fibres, on the periphery of the syno- vial membrane. An internal and an external lateral ligament, with the synovial membrane, constitute the whole apparatus. The Internal Lateral Ligament, also called the Deltoid, (Lig. Deltoideum) arises from the whole inferior margin of the malleo- lus internus, and w7ith particular strength from the depression which exists in it: it then descends and is inserted into the in- ternal face of the astragalus, and into the lesser apophysis of the os calcis, which lies just below it. This ligament is broad, thick, quadrilateral, and composed of fibres which descend obliquely backwards. The tendon of the tibialis posticus runs in a troch- lea which is formed on the internal face of this ligament. The External Lateral Ligament (Lig. Triquetrum) consists in three distinct fasciculi, of which one is anterior, another posterior, and the third in the middle. The anterior arises from the lower extremity of the malleolus externus, and, running inwards and forwards, is inserted into the outer face of the astragalus in front of the surface for the fibula. The posterior arises from the de- pression in the extremity of the malleolus externus, and, running inwards and backwards, is attached to the point of the astraga- lus, at the outside of the groove, for the tendon of the flexor pol- licis. The middle arises from the pointed termination of the malleolus externus, and, descending beneath the tendons of the peronei muscles, is attached to the external face of the os calcis, below the surface for the astragalus. These fasciculi are com- 310 SKELETON. posed of strong longitudinal and parallel fibres. The posterior is larger than either of the others, and occasionally detaches a part which is inserted into the posterior margin of the articular face of the tibia. The Synovial Membrane is reflected, as usual, over the arti- cular surfaces, and from one bone to the other. It sends up a short process of a line in length between the tibia and the fibula. It is remarkably loose in front and behind, and has on its super- ficial face a considerable quantity of adipose matter, which can- not be easily detached from it. It commonly contains an unusual quantity of synovia. Of the Articulations of the Foot. Of the Tarsal Articulations.—1. The Os Astragalus is united to the os calcis by a double articular surface, which has been described. The ligaments which hold them together are as follow:— The Interosseous Ligament is placed between the two bones, so as to occupy the large oblique fossa between the double ar- ticular surface in each. It is a collection of very strong, short fibres, with interstices for fatty matter, which, arising from the whole length of the groove in the astragalus, descends to be in- serted into coresponding points-in the groove of the os calcis. Where the fossa is narrow, as it is behind, the ligament is thin and flat, but it augments considerably in front, where there is more room for it. The posterior Ligament arises from the posterior margin of the astragalus, and, descending obliquely inwards, is inserted into the adjacent portion of the os calcis. Its fibres are blend- ed with those of the Deltoid Ligament, and on their posterior face they form a ligamentous trochlea for the tendon of the flexor pollicis. This articulation is also strengthened by the insertion of the lateral ligaments of the ankle joint into the os calcis. The Synovial Membrane forms a distinct cavity on the pos- ARTICULATIONS OF THE LOWER EXTREMITIES. 311 terior and larger articular face of the two bones, and is in con- tact with the fatty matter in advance of the tendo-achillis. 2. The Articulation of the Astragalus with the scaphoides is formed by the convex head on the part of the former, and by the concavity on the part of the latter. It is covered, above, by a thin, broad ligament, with parallel and oblique fibres, which, arising from the superior and internal face of the astragalus, are implanted into the upper face of the scaphoides, some of its fibres extending over to the cuneiform bones. It is covered, above, by the tendons of the extensor muscles of the toes and of the tibialis anticus. On the under surface of the foot, this articulation is support- ed by two ligaments, called the Calcaneo Scaphoid, (Lig. Pla- num,) from their origin and insertion. The interior one arises from the internal margin of the lesser apophysis of the os cal- cis, and, running obliquely forwards and inwards, is inserted into the under and internal surface of the os scaphoides. It is a very thick, flattened fasciculus, on the under surface of which is formed the ligamentous trochlea?, in which run the tendons of the flexor pollicis and flexor longus digitorum, and which surface is also in contact with the tendon of the tibialis posti- cus. By subtending the head of the astragalus, it contributes largely to the keeping of it in its place in the erect position. The External Calcaneo Scaphoid Ligament, placed at the outer margin of the last, arises from the under surface of the greater apophysis of the os calcis, and running obliquely inwards and forwards, is implanted into the under external surface of the scaphoides. It consists in two or more short, strong fasciculi. The Synovial Membrane of the articulation between the as- tragalus and the scaphoides covers the articular faces of these bones, and lines the ligaments above and below. A reflection of it, also, lines the articulation between the os calcis and the astragalus, in front of the rough fossa which is occupied by their interosseous ligament. 3. The Calcaneo Cuboid articulation, formed by the two 312 SKELETON. bones indicated in the name, is maintained by two ligaments, one above, the other below, and by a synovial membrane. The Superior Calcaneo Cuboid Ligament arises from the up- per anterior surface of the os calcis, and is inserted into the ad- joining upper surface of the cuboides. It is broad, thin, and quadrilateral, with short parallel fibres, and is in contact, above, with the peroneus tertius tendon. The Inferior Calcaneo Cuboid Ligament, (Lig. Plantare,) placed on the plantar surface of the foot, is remarkable for its size and extent. It consists of two horizontal planes of fibres, of which the superficial is the longest. The latter arises from the back under surface of the os calcis, and, advancing forwards, its fibres are inserted into the summit of the ridge which tra- verses the cuboides obliquely; the greater part of them, how- ever, go beyond this point, and, dividing into fasciculi, are in- serted into the base of the third and fourth metatarsal bones. The tendon of the peroneus longus is confined between these fas- ciculi and the under surface of the cuboides. The other plane of this ligament being more deeply seated, is also shorter. It arises from the front under surface of the os calcis, where the tuberosity exists at this point, and, by advancing, is inserted en- tirely into the oblique ridge of the cuboides. The Synovial Membrane being reflected over the articular surfaces of the bones, and lining the ligaments, is uncovered at several places above, where interstices exist between the fibres of the superior ligament, and externally it is contiguous to the tendon of the peroneus longus. 4. The Scaphoid and the Cuboid bones touch at the external posterior angle of the cuneiforme externum, and form, there, occasionally, a distinct articular surface, with a synovial mem- brane. Besides this mode of union, an interosseous ligament is introduced between them; on the dorsum of the foot there is a transverse ligament running from one bone to the other be- neath the extensor tendons; and on the sole of the foot there is an oblique ligament, which, arising from the under surface of ARTICULATIONS OF THE LOWER EXTREMITIES. 313 the scaphoides, is inserted into the anterior internal margin of the cuboides. The articular surfaces of the Cuboides and Cuneiforme Ex- ternum, which are in contact, besides a distinct synovial mem- brane, are secured by transverse and oblique ligamentous fibres going from the one bone to the other. 5. The Articulation between the scaphoides and the three cu- neiform bone's is secured by a dorsal and a plantar ligament. The former, arising from the back of the scaphoides, is divided into three fasciculi, that go, respectively, to the back of each cunei- form bone; of these, the internal is the strongest, and is parti- , cularly well marked on the internal face of the cuneiforme in- ternum. The plantar ligaments are, also, three in number, and, having a sort of common base from the under surface of the scaphoides, by being divided into three fasciculi, as the above, are inserted into each cuneiform bone. They are not so well marked as the upper ones. The cuneiform bones are also connected together above and below, by short transverse ligaments going from one bone to the other, and holding their lateral surfaces in contact. Those below are not so distinct as the upper ones, and are blended with the insertions of the tibialis posticus. One synovial membrane covers the articular surfaces of the scaphoides and of the cuneiform bones which are in contact; and it extends itself by digital processes between the first and second, and the second and third cuneiforms, so as to line also the articulations there. The process between the two latter is much shorter than the process between the other two, which extends itself into the tarso-metatarsal articulations, after the same principle which is observable in the hand. Of the Tarso-Melalarsal Articulations. The articular faces of the bones, here, having been sufficient- ly described, it is to be noted in addition, that besides being co- Vol. I.—40 314 SKELETON. vered with cartilage, they have the apparatus of the moveable articulations, generally, in ligaments which hold them toge- ther, and in synovial membranes. The ligaments are above and below. 1. The,articulation of the first metatarsal bone with the cu- neiforme internum is one-third of an inch in advance of the next, and completely insulated by its synovial membrane: it is strong- ly secured by ligamentous fibres above, internally and below, which give it almost a complete capsule. 2. The dorsal or upper ligaments of the remaining metatar- sal bones are arranged as follow. There are three for the second metatarsal; one comes from the second cuneiform, one from the first, and another from the third: the two latter are oblique; and they all converge to be inserted into the base of the bone to which they belong. One dorsal ligament passes from the third cuneiform to the base of the third metatarsal; it is sometimes assisted by a fasciculus from the cuboides. From the superior face of the cuboid bone a fasciculus is sent to the base of the third and fourth metatarsals. The plantar or under ligaments are arranged on the same plan with the dorsal. Not being quite so strong, they are re- enforced by the fibrous sheaths of the flexor tendons which lie upon them. The synovial membrane, which is reflected over the articular surfaces between the second and third metatarsals and their cor- responding cuneiforms, is the elongation of the digital process sent from the scaphoid articulation between the first and second cuneiforms. This process, besides extending to the aforesaid tarso-metatarsal articulations, insinuates itself to the articular surfaces on the sides of the second metatarsal bone; but a dis- tinct synovial capsule is sometimes formed between the base of the third and fourth metatarsals. One synovial membrane is reflected over the surfaces, between the cuboides and the two last metatarsals, and sends in a pro- ARTICULATIONS OF THE LOWER EXTREMITIES. 315 cess between the latter. In all these cases the synovial mem- branes line the dorsal and plantar ligaments of their respective articulations. Of the Metatarsal Articulations. The metatarsal bones, with the exception of the first, articu- late with each other by the contiguous faces of their roots, which has just been stated, along with the manner of their getting at these points, a lining of synovial membrane. They are farther fastened to each other by short transverse ligamentous fasciculi, which pass from the base of one to the base of the adjoining. These fasciculi exist both on the upper and under surface of the bones, and are, therefore, denominated dorsal and plantar meta- tarsal ligaments. There is-also a description of interosseous liga- ments between the bases of these bones, occupying the space in- termediate to the dorsal and plantar ligaments of each. The anterior extremities of the metatarsal bones are not in contact; they are, however, fastened to each other by a trans- verse ligament on their under surface, the fibres of which are somewhat blended with the capsular ligaments of the first joints of the toes. Of the First Joint of the Toes. The surfaces of the bones here being covered with cartilage, are formed into an arthrodial articulation. There is a fibrous capsule surrounding the articular faces, and enclosing the sy- novial membrane. This capsule is considerably thickened be- low, where the flexor tendons pass over it; above, it. does not exist, as the extensor tendon is there lined by the synovial membrane: on each side it is also thickened, so as to form a la- teral ligament. In the under part of the capsule of the great toe, we find on each side the sesamoid bone. These joints re- semble so strongly the corresponding joints of the fingers, that a farther description is unnecessary. 316 SKELETON. Of the Second and Third Jomts of the Toes. From the shape of the surfaces of the bones composing them, these are simply ginglymous articulations. They have their cartilaginous incrustations, synovial membrane, and capsular ligament. The under part of the latter is much thickened, and forms a trochlea for the flexor tendons; on each side it is ar- ranged into a lateral ligament, and above it is defective, as the synovial membrane is in contact with the extensor tendon. These joints also resemble so strongly the corresponding ones of the fingers, that farther description is unnecessary. BOOK ir. PART I. Of the Integuments of the Body. The integuments of the body consist i'n the Cellular and Adipose Substance, and in the Dermoid Covering. CHAPTER I. OF THE CELLULAR SUBSTANCE. The Cellular Substance (Texlus Cellulosus, Mucosus) is an elementary tissue, and is more generally disseminated than any other of the body, for it seems to be quite as indispensable to the latter as moisture is to vegetables. It is found abundantly beneath the skin; between muscles, in the interstices of mus- cles and of other parts; connecting membranes to one another; surrounding organs; entering into their composition; gluing them together; in fine, under every variety of circumstance and locality which the human organization admits of. Indispensa- ble as it is to the texture of all other parts, we find it, as may be expected, preceding them in the development of the foetus; at which period it is in the condition of a fluid slightly coagulated. When examined with a microscope, as it winds around a muscle and introduces itself between the fasciculi of its fibres; it will be seen that, however fine the latter may be, yet this body is interposed between them in thin laminae. On separating these fibres, the intervening laminae are resolved or drawn out 318 INTEGUMENTS. into fine filaments, which finally, break after being stretched to a certain extent. The lamina which surrounds the whole body of the muscle and constitutes its sheath, on being put upon the stretch, also tears after having been attenuated into still thinner laminae and into fibres. If air be blown into the sheath of a muscle, this sheath is dis- tended into a multitude of cells of various forms and sizes, which have no determined shape, and do not return to the same upon a repetition of the inflation. These cells communicate very freely; all limpid fluids pass with the greatest easeTrom one to the other, so that from any single point they may, by the force of injection, be distributed throughout the body; this is mani- fested in emphysema, where, from a small wound in the thorax, air becomes universally diffused. Fluids of any kind, except they be inspissated, when deposited in these cells, are subject to the common laws of gravity, and continue to descend succes- sively from the higher to the lower cells, as in anasarca. Blood traverses them very readily in ecchymosis. Cellular tissue enjoys a good deal of elasticity, for when stretched it readily returns upon itself. When very thin, as between the fibrillae of muscles, it is colourless or nearly so, and of a gelatinous or glue-like consistence; but when its laminae are thicker, it is of an opaque white, and has a strength amounting almost to that of ligamentous matter. When dried it becomes crisp and of a dark brown; but may be restored to its colour and condition by soaking in water. It is only very slightly affected by the usual heat of the culinary processes of roasting or boiling, as our dishes of meat daily prove; but ma)' be resolved into ge- latine after a protracted ebullition. Its putrefaction is slow, and cannot be accomplished, by maceration, under several months. The cellular substance is pervaded by a large number of blood vessels, the majority of which do not, in a natural state, convey obviously red blood; but if any portion of it be exposed for a short time to the air, or to any other unusual stimulus, it quick- ly becomes suffused with red blood, circulating through an in- finitude of channels. It cannot, however, be conceded, as Ruysch supposes, that it is formed exclusively of blood vessels. Some anatomists, indeed, as Haller and Prochaska, allow that CELLULAR SURSTANCE. 319 though blood vessels ramify through it, yet they are not spent upon it, or do not form a part of its organization. The distinc- tion is rather too subtle to be readily admitted, and seems, more- over, to be refuted by the continued exhalation and absorption which is going on within. It does not appear that nerves are spent upon the cellular substance, though they pass abundantly through it to their respective organs. It is probable that the granulations on which injured parts of fhe body depend for their restoration, arise from this cellular substance. The late Professor Wistar attended a patient for compound fracture of the leg, with a large wound, which was subsequently covered with' luxuriant granulations. The limb was suddenly attacked with an cedematous swelling, which ex- tended itself to the sore, and caused its granulations to tumefy, so that they pitted upon pressure precisely like other parts.* The most generally received opinion of anatomists,! in re- gard to the arrangement of cellular tissue is, that it results from the assemblage of a multitude of lamellae, and of fine soft fibres, which, being variously interwoven, produce a series of cells all communicating one with another, but varying in their shape and size; so that their whole cellular substance may be consi- dered to represent a single cavity subdivided into an infinitude of smaller ones. To this it is objected,J that when this tissue is accurately examined, it appears rather as a homogeneous, viscid, and only partially solidified substance; particularly in the inferior orders of animals, and in the embryo state of the ' more exalted, where it has still to admit the deposite or forma- tion of the several organs. That the same is manifested at any period of life; for neither with the naked or assisted eye does it assume any other appearance. That its laminated and fibrous condition, when such does appear, is owing to its glutinous or glue-like consistence, which causes it to assume a factitious ar- rangement upon being drawn or inflated. For example, if one separates two muscles for a short distance, the cellular substance * System of Anat. vol. i. p. 388, 2d edition. | Haller, Beclard, Bichat, Wm. Hunter, &.c. i Bordeu, Recherches sur le Tissn Muqueux et Celluleui. Paris, 1790. J. F. Meckel, Manuel D'Anat. vol. i. p. 105. 320 INTEGUMENTS. between them becomes unequal and furrowed without losing its cohesion; but if they be farther separated, filaments and cylin- drical columns are produced. If the traction be then suspended, and the muscles replaced, the filaments shorten, and are finally united into a consistent mass whose parts all adhere together.* While such tractions are going on, it most frequently hap- pens that air is insinuated into the cellular substance, from which comes the appearance of small cells and vesicles: upon the es- cape of this air, the primitive state of cohesion is restored, and, upon a renewal of the traction, cells of a different shape, size, and appearance arise. Again, if air be so introduced, one may push it in any direction, separate its globules, collect them again, and into larger masses; vary their shape, and, in fine, by such means mould the supposed cells into an infinity of forms. From these considerations, the inference is plain, that when cellular substance is drawn it must yield itself into filaments; when in- flated, as the air acts in every direction, its supposed lamellae must.be separated and assume a cellular shape; and, by the ap- plication of both forces at once, it may be caused to assume both a cellular and a filamentous appearance. Upon the whole, Meckel conceives that the term Mucous Tissue, adopted by Bordeu, is much more exact than the one of Cellular Tissue, now most generally used. Notwithstanding the perfect continuity of the mucous or cel- lular substance throughout the body, anatomists for the ease of description have divided it into External and Internal. The External Cellular Substance (Texlus Cellulosus Inter- medins, seu laxus) has the general extent and shape of the body and of its organs, so that if it were possible to extricate the lat- ter from their envelope, it would present a chamber for the lodgement of each part. But the walls of these chambers would not all be of the same thickness, as the quantity of cellular sub- stance varies. In the cranium and spinal cavity there is very little of it; on the surface of the head and in the orbits more: about the trunk, both internally and externally, it is abundant; in the extremities still more so, where it penetrates between the^, muscles. In the arm pit, in the groin, and in the heck, all * J. F. Meckel, loc. cit. CELLULAR SUHSTANCE. 321 parts where much motion is enjoyed, it is unusually abundant. The foramina of the cranium and of the spine, establish the points of connexion of the cellular substance of these parts with others adjacent. The cellular substance of the face is continued into that of the neck; that of the latter is continued through the upper opening of the thorax upon the viscera of this cavity; and thence through the openings of the diaphragm, along the great vessels and oesophagus upon the viscera of the abdomen and pelvis. The cellular substance of these cavities is again con- tinuous with the deep-seated cellular substance of the limbs, at the arm pit and at the groin. The trunk of the body being en- veloped by one broad sheet of cellular substance, it is continued superficially to the limbs.* With this general sketch of the distribution and extent of cellular substance, it is not surprising that in certain bad cases of emphysema, the air shows itself every where, even at points the most remote from the lungs, and apparently the least ex- posed to the accident, as the interstices of muscles, of glandular organs, and so on. It will also now be understood how this varied distribution of cellular substance and its proteiform shape, have been the inexhaustible but delusive source of anatomical discoveries and supposed novelties, under the name of fasciae, sheaths of vessels, and so on; and will continue to be so, to such as do not recollect that all these things are included under the general character of this tissue; and that each muscle, each vis- cus, each nerve, and each blood vessel, has its own particular chamber under this multiform arrangement, which chamber may be traced to or from any other point, according to fancy. At the same time it should be noted that many of the laminae have a condensed form, which renders a special knowledge of them of the greatest use to the surgeon, and which is elsewhere succinctly pointed out, with the description of their respective organs. • For a detailed account of the inflections of the cellular substance, the student may consult with advantage, Bordeu, loc. cit. Bichat, Anatomie Generale; Systeme Cellulare. Paris, 1818. Andreas Bonn, de Continuationibus Membranarum, in Sandifort's Thesaurus Dissertationum, Rotterdam, 1769. Haller, Element. Physiol, vol. i. 1757. Vol. I.—41 322 INTEGUMENTS. Anatomists who lived at a period much less illuminated than the present on the subject of the elementary tissues of the body, seem, however, to have seized upon the idea of the universal inflection of cellular substance over the surfaces, and through the texture of the several organs. Mangetus,* without pretend- ing to originality, but in alluding freely to the observations of others, says, " Membrana adiposa, est expansio cellulosa, quae totum corporis habitum, paucissimis, iisque minimis partibus exceptis, circumambit; et in qua materia albicans unctuosa, sensu expers, ad partes fovendas ac lubricandas colligitur.—Haec mem- brana cellulosa seu pinguedinosa, non tantum in exterioribus corporis reperitur; sed interus in intestinis, mesenterio, aliisque prope omnibus partibus, non exceptis etiam vasis sanguiferis, ut suo loco videbimus, observatur." And in describing the apo- neurotic covering of the body and of the limbs, which in his day was called Membrana Musculosa, from some false notions of its nature, he adds, " Dicitur oriri a dorsi vertebris, quia scilicet earum spinis firmiter adhaeret, inibique multo quam alibi usquam robustior conspicitur. Usus est, musculos universim in sua sede firmare, iisque quasi thecam praestare, in qua ut supra in- < nuimus laxius sibi cohaerente lubrice moveri quent." The cel- lular investments of the muscles the same author calls Mem- brana, Musculi Propria, and he speaks of their penetrating be- tween the fasciculi of muscles, and most evidently those of the glutaeus maximus and deltoides. The Internal Cellular Membrane (Textus Cellularis Stipatus) presents itself under different arrangements according to the organ or part whose interstices it penetrates. As it forms in the muscles an envelope for each fasciculus and fibre, if the lat- ter by any art could be withdrawn, it would represent a conge- ries of fine parallel tubes. In the case of glandular bodies the internal cellular membrane imitates the shape of their lobes, lobules, and acini or small graniform masses, and may, there- fore, be compared to a sponge. In the hollow viscera, as the stomach and bladder, it unites their successive laminae to one another. In the ligaments, even where the first fibrous struc- * Theatrum Anatomicum, Geneva, 1716, vol. i. Ch. iii. CELLULAR SUBSTANCE. 323 ture is distinct, the latter are united by cellular tissue in their interstices. The tissue is not sufficiently abundant in the bones, tendons, or cartilages, to be very distinct; but from what is seen of it in the forming stage of the embryo, it is nevertheless ascertained to be the base of every part. In glandular textures it is frequently spoken of under the name of parenchyma. Most of the membranous textures of the body may by ma- ceration be resolved into this mucous or cellular tissue, so that we hear anatomists, without hesitation, asserting, that under va- rious degrees of consistence, it forms the skin, the serous mem- branes, the vessels, the ligaments, in short, almost every thing excepting the muscles, the nervous system, and the glands, and they only depart from it in having their globules deposited in its interstices.* Meckel even adds to the list the epidermis. The term mucous tissue was substituted for that of cellular, by Bordeu,t owing to its glue-like consistence, and to its re- semblance to the corpus mucosum of vegetables. Notwith- standing its propriety on these grounds, yet as the lining mem- brane of all the hollow viscera has the same name, some confu- sion may be produced unless one bears in mind the distinction. Bordeu has expressed the character of the internal cellular mem- brane very forcibly in saying, that in embryos all their organs are species of buds, which vegetate in the cellular tissue, like plants do in the open air, or their roots in the ground, and that each one having an apartment of its own, this apartment is to it a cellular atmosphere, which keeps in a perfect relation with the action of the organ.J In tracing many of the laminae of the cellular substance, we find, that as life advances, they assume a more fibrous character than what they possessed in. infancy; this also occurs when they * Beclard, Anat. Gen. p. 141. Haller, loc. cit. p. 19; vol. i. p. 113. j- Loc. cit. % Loc. cit. p. 65. Recherches Anatomiques sur les Glands, Paris, 1752. Also, An Exposition of the Physiol, and Pathol. Doctrines of Theoph. Bordeu, under- stood to be from the pen of a learned friend, R. La Roche, M. D., in the North American Med. and Surg. Journal. Philad. April, 1826. 324 INTEGUMENTS. are pressed upon by tumours, or irritated from many other causes. This disposition of the cellular substance to assume a ligamentous character, in many of the attachments which are formed between the two tissues, frequently leaves it doubtful with which the membrane under examination should be classed; in some individuals the fibrous substance is predominant, and in others the cellular. This deposite of fibrous matter into cel- lular substance, or rather the change of the latter into it, may be compared to the partial or even perfect conversion of the cartilages of the thorax into bone by an increased deposite of the phosphate of lime. It perhaps will be better understood by repeating that this cellular tissue is an elementary one, where- as the ligamentous is composite. In addition to the uses of the cellular substance in forming a nidus for the deposite of all the molecules of the body, and in circumscribing each organ, so as to keep it distinct from the contiguous ones of a different character, its elasticity and yield- ing nature permit it, in the movements of the several parts upon each other, to change its position, and upon the cessation of the active cause, to re-establish itself. Its extreme flexibility is kept up by a continued exhalation of moisture from the arte- ries that ramify through its texture. This cellular serosity, when an animal is recently killed, and its internal parts ex- posed to a cold atmosphere, rises in the form of vapour, and has a particular smell. It is more abundant in certain parts than in others; and, as a general rule, where there is the least adipose matter. Indeed, these two substances seem to exist in an inverse ratio: in a person, for example, who has died very fat, the parts are comparatively dry; whereas, in such as have all the adipose matter wasted by a lingering disease, there is a humidity which quickly disposes to putrefaction; a fact fre- quently exemplified in our dissecting-rooms. The cellular se- rosity is, consequently, more abundant in the scrotum, in the eyelids, and in the penis. Bichat informs us, that he has satis- fied himself by experiments, of its augmentation during diges- tion, during heavy perspirations, and after sleep; which will ac- count for the swelling of the eyelids, so commonly observed in the morning, upon rising. ADEPS. 325 This serosity is albuminous, as proved by its being coagu- lated by alcohol, and by the mineral acids. It is removed by the absorbents; assisted by the tonic contraction of the cellular membrane, according to M. Beclard.* The latter author, in- deed, goes on to say, that the cellular membrane is the essential organ of absorption, by which the skin and the villosities of the internal membrane of the hollow viscera perform this function. That the substances introduced through it into the blood ves- sels, no doubt, in doing so, undergo some kind of elaboration, in the same way that those do which are deposited in its inter- stices for the growth, repair, and changes of the body. CHAPTER II. OF THE FAT, (ADEPS.) The Adeps, in subjects of moderate corpulence, is found be- neath the skin; between it and the fasciae; and in the layers of condensed cellular substance which are next to the muscles; as on the face, the neck, the trunk of the body, the buttocks, the limbs, the palms of the hands, and soles of the feet. In the adult, it is also found between the serous membranes and the cavities which they line, as in the thorax and abdomen; it is also found between the laminae of these membranes, as in the omenta, mesentery, and so on. It, likewise, exists between the interstices of muscles; in the bones, and elsewhere; so that its whole amount is estimated at about one-twentieth of the entire weight of the body. There are, however, certain portions of the body, where its presence would have been very inconveni- ent: they, accordingly, are destitute of it; to wit, the interior of the cranium, the ball of the eye, the nose, the ear, the intestinal canal, the eyelids, the scrotum, the penis, the labia interna, and the substance of the glands. * Anat. Gen. p. 149. 326 INTEGUMENTS. The adeps is of a yellowish colour, and in a semifluid state in the living body, when after death it has got a few degrees below the standard of animal heat, it becomes somewhat solidi- fied, and then appears in small aggregated masses of different shapes and sizes. In chemical composition it differs from all other parts of the body by the absence of nitrogen, and is formed of oxygen, hy- drogen, and carbon, which render it, in animals, a very suita- ble article for candles and lamps. According to the analysis of Chevreul,* it consists of two kinds of matter, elain and stea- rin, the former of which remains fluid at the freezing point, while, as mentioned, the other becomes solid by a very small abatement of its living temperature. The application of porous paper enables one to separate them in a small way. The adeps, though lodged in the cellular substance, is accom- modated there under different circumstances from the cellular serosity, and is supposed to be in different cells. This doctrine was promulgated by Dr. Wm. Hunter,f and upon the following grounds. That certain parts of the cellular membrane are des- titute of it; that in persons who have died from dropsy, the portions of the cellular membrane which originally contained fat, have a more ligamentous condition than others; to wit, those on the loins next to the skin, more than the stratum next to the lumbar fascia; that water or fluids pass readily from a higher to a lower part of the cellular membrane, either when extrava- sated naturally or injected; that oil, when injected artificially, subsides in the same way, and has a doughy or cedematous feel, yielding readily to pressure and pitting, whereas, fat never shifts its position simply from gravitation. From these several causes, Dr. Hunter adopted the opinion that the oil of the cellular membrane is lodged in peculiar vesi- cles, and not as the water of anasarca, in the reticular inter- stices of parts. This idea has been adopted by Beclard, who says that the lobules of fat, when examined with a microscope, are seen to be composed of small grains or vesicles, from the six hundredth to the eighth hundredth part of an inch in diame- * Annates de Chimie, vol. xciv. f Medical Observations and Inquiries. London, 1762. ADEPS. 327 ter, each one having a pedicle furnished from the adjacent blood vessel. That the parietes of the vesicles are so fine as to escape observation, but that he considers them as arranged in the same way with the pulp of oranges, lemons, and such kind of fruit. These several reasons are so plausible that I cannot but subscribe to their force and accuracy, notwithstanding the objection raised from other quarters of high authority. In the infant the fat is found at the surface of the body chief- ly, little or none existing in the interstices of muscles, and in the cavities. It is more abundant in the female than in the male, and in both sexes it is removed as life declines. Its uses are not fully understood. At some points it serves to diminish pressure, as on the hands and feet; at others it fills up interstices; it is also a bad conductor of caloric, and may, therefore, serve in retaining animal heat. But its most general application is to the purposes of nutrition, it being one of those forms which nutritive matter assumes previously to being per- fectly assimilated. This is very fully manifested in hibernating animals, which being fat in the beginning of their torpid state, return from it quite lean; and in insects which during their re- pose in the chrysalis state, live upon their own fat while under- going the metamorphosis into the perfect animal.* * Beclard, Anat. Gen. p. 170. BOOK II. PART II. Of the Dermoid Covering. The Dermoid Covering, or tissue of the body, consists in the Skin;—its Sebaceous organs;—the Nails;—and the Hair. CHAPTER I. OF THE SKIN. The Skin (Pellis, Cutis, hpi**) is extended over the whole surface of the body, and thereby constitutes a complete invest- ment of it. At the orifices of the several canals which lead into the interior of the body, as the mouth, nose, vagina, anus, and urethra, it does not cease abruptly, but is gradually converted into the mucous membrane of the part, so that it is plainly con- tinuous with it. At certain places, on the middle line of the body, the junction of the skin of the two sides is indicated by a change in its appearance, called Raphe; as on the upper lip; from the navel to the pubes; on the scrotum, and in the perineum; in all of which places, in the development of the foetus, the two sides of the body are later in uniting than elsewhere. The colour of the skin varies in different nations: it is black in the negro; of a copper colpurin the American savage; bronzed, or tawny, in the Arabian; and white in the Europeans and their descendants. It is also subject to various shades, from the mix- ture of these races, and from the influence of climate; its general Vol. I.—42 330 INTEGUMENTS. tendency being to turn dark on parts exposed to the influence of tropical heat and light. The external surface of the skin, or that which is free, has on it a great multitude of wrinkles; some of them depend upon the subjacent muscles, as on the forehead and face; some are caused by the flexions of the articulations, and are to be seen at all of these places on the limbs; in addition to which, where there is much emaciation of the parts beneath, the skin not having suffi- cient elasticity to accommodate itself to their state, is thrown into other wrinkles, and sometimes into loose folds. Finer wrinkles of another description are also found on the skin, ar- ranged into various angular and spiral directions: they depend on an entirely different cause, which will be treated of else- where. The skin also abounds in hairs, which vary in fineness and in length according to the region over which they are distri- buted: it, likewise, presents many small pits, or follicles, which are the orifices of sebaceous glands: a finer description of pores, which are visible only to the assisted eye, are supposed to be the orifices of exhalents and of absorbents, but this is not quite certain. The internal surface of the skin is connected to the subja- cent parts by the cellular tissue, which permits a considera- ble sliding of it backwards and forwards on most parts of the body; on others, however, this is restrained, as on the cra- nium, the palms of the hands, and the soles of the feet, by ligamentous fibres passing to it from the fascias and bones below. A very interesting attachment of this kind is seen on the fingers, where a plane of ligamentous fibres is seen passing from each side of the head of the first phalanx, down- wards, to be inserted into the skin, half an inch or an inch off. Since the first observation of Malpighi, on the tongue of a bullock, whereby he ascertained that its integuments consisted in three layers, and the discovery of a similar arrangement on other portions of the integuments by Ruysch,* anatomists have, for the most part, admitted the skin to consist of three laminae, the Cutis Vera, the Rete Mucosum, and the Cuticula. * Thesaurus, Anat. IX. CUTIS VERA. 331 SECT. I.--OF THE CUTIS VERA. The True Skin (cutis vera, derma, corion,) is the deepest, or the layer next to the cellular substance. Its thickness varies ac- cording to age, sex, and the region of the body over which it is stretched; on the trunk it is thicker behind than it is in front; on the limbs, thicker on their external than on their internal faces or semi-circumferences. On the mammae, the penis, scrotum, and external ear, its tenuity is remarkable. When uninjected, it is perfectly white in people of all complexions, and in the living state has a semi-transparency that permits the blood of the veins to be seen beneath it. The internal surface of the true skin is so blended with the cellular substance, that in the recent subject there is a difficulty in distinguishing where one terminates and the other begins, yet they may be separated ky maceration so as to determine this line; mortification of the cellular substance sometimes does the same thing; and in the ham, cured by salting and smoking, the true skin, after boiling, may be stripped off with but little diffi- culty. In either of these cases the internal surface of the latter is seen to be studded with small areolar depressions, caused by the projection of the granulated masses of adeps; the margins of those alveoli are the principal points 6f adhesion to the subcuta- neous cellular tissue, while their bottoms are pierced with small openings, that lead through the skin. The external surface of the true skin is covered with very fine papillae, or villi, (Papilla Tactus,) that are readily brought with- in the observation of the naked eye, by maceration, when pro- tracted long enough to permit the separation of the cuticle. The projections on the tongue are very similar to them, and the whole are designated as the papillary body. The cutaneous papillae are particularly distinct at the bulbous ends of the fingers and toes, upon the palms and soles, on the lips, on the glans penis, and the nipple; in other parts they are not so evident, but still there can be no doubt of their existence, from analogy. On the hands and feet they are arranged in double rows or files, which 332 INTEGUMENTS. occasion the semicircular and spiral turns of small wrinkles or ridges at the ends of the fingers and toes; and the transverse, ob- lique, and curved ones, on other parts of the soles and palms. The small, triangular, lozenge-shape, and multangular elevations of the cutis vera, seen elsewhere on its external surface, are caused rather by its contraction than by the papillae. These papillary projections resemble very much small conoi- dal, cotton-like filaments, standing up the twelfth of a line, or thereabouts, from the surface of the skin; they are by no means so long as the villi of the intestines, and, like them, consist in very delicate ramifications of nerves and blood vessels, united by cel- lular tissue. In places where these papillae are less abundant, the cutis vera is not so vascular or sensitive. They readily re- ceive a fine injection, and, if the cuticle be afterwards separated by maceration, their vascularity is very distinct. Their nerves are destitute of neurileme.* The texture of the true skin is fibrous; the fibres which com- pose it, by their irregular intermixture, resolve it into a mass of net-work or areolae, the meshes of which are sufficiently large in some parts to permit the introduction of the head of a small pin. The meshes, though they are larger and more distinct on the in- ternal than on the external surface of the true skin, open, how- ever, upon the latter surface; having passed through the skin ob- liquely, after the manner of the ureters through the coats of the bladder. Those intervals between the fibres of the skin are ren- dered very obvious after a maceration of a month or two, or after a skin has been tanned. They serve to transmit hairs, blood ves- sels, nerves, absorbents, and exhalent vessels, also, if such exist. These interstices communicate freely with the cellular substance, for in many cases of anasarca, blisters, when made upon a de- pending part, empty the cellular membrane of water almost as quickly as scarifications ;f but if the blisters inflame, they dis- charge inconsiderably, owing to the porosities being shut up by the tumefaction and fulness of the parts. The same is observa- ble in scarifications. A fine injection, when forcibly driven into the extremities of a foetus, will become extravasated between the * Beclard, Anat. Gen. f W. Hunter, loc. cit. RETE MUCOSUM. 333 cutis vera and cuticle, and raise up the latter in small blisters, as I have frequently experienced, though it cannot be caused to pass through the cuticle. The precise nature of the tissue which composes the true skin is not yet ascertained; it seems, however, to be a mixture of cel- lular substance and ligamentous matter; with a striking predomi- nance of the latter in most parts of the body, though its propor- tion varies considerably, being very abundant on the thickest parts of the skin, while it is scarcely discernible on the thinnest. The following analogies of dermoid with ligamentous or desmoid tissue are observable. It becomes yellow and transparent on be- ing boiled, and a continuation of the process dissolves it into ge- latine. It resists putrefaction for a long time, and is remarkably tenacious. Contrary, however, to ligamentous matter, it is ex- tensible and elastic, though this property may arise from the ob- lique intertexture of its fibres; as a bandage from a piece of muslin, when torn longitudinally or transversely, is inelastic, but if it be cut bias, it is then very elastic. The application of tannin increases its resistance, and makes it one of the strongest animal substances known in human arts. The skin has a very strong power of contraction, which is manifested in an amputation, in a long incised wound, or when a sensation of chilliness exists, as in an ague or from the applica- tion of cold. Owing to the diminution in size of its areolae, its external surface then becomes wrinkled, rough, and studded with projecting points, constituting the Cutis Anserina. The cutis vera is very vascular, and abounds also in nerves and absorbents. SECT. II.--OF THE RETE MUCOSUM. The Mucous Net (Rete Mucosum*) of Malpighi, is the second layer of the skin, and is that in which resides the colour of the several races of men. It covers every part of the surface of the cutis vera; its existence, however, is not so obvious beneath the nails and about the junction of the skin with mucous membranes, as it is elsewhere; though taking all things into consideration, it is probable that it exists also at these several places, but much * Caldani, Icon. Anat. Pi. xc. xci. Albinus, Annot. Acad. Leyden, 1756. Ruysch, Thes. Anat. ix. 334 INTEGUMENTS. finer. It is so extremely thin, and of such a soft mucilaginous consistence, that it is difficult to separate it as a distinct lamina, either by maceration or by any other means; for it most com- monly peels off by adhering to the cuticle, after the manner of a pigment. It, however, by good management, may be fairly raised as a membrane, and separated for a certain distance from the other two coats of the skin. Fine as this membrane is, it would seem, from the observations of Mr. Cruikshank* upon a negro dead from small-pox, and upon an injection executed in London, by the late Dr. Baynham, of Virginia,f ana< from more recent experiments in Paris, by M. Gaultier,J that it consists in several layers. 1. Upon the in- equalities or papillae of the cutis vera, there is a layer called, by M. Gaultier, bloody pimples, (Bourgeons Sanguins,) but which in the opinion of some other anatomists are only the papillae them- selves of the cutis vera. 2. Then there is a very thin and trans- parent coat, called, from its colour, Tunica Albida Profunda: it is especially visible in the negro; under the coloured horns and scales of animals, and beneath the nails of white persons. 3. Over this layer is spread another, (the Gemmula,) which contains the colouring matter of the several complexions of the human family, and consists in a multitude of dark brown points in the negro; it is visible also in those forms of disease called ephelides (freckles,) by the French, where the skin becomes spotted; it is not so dis- tinct in the healthy state of the white individual. 4. The last lamina of rete mucosum, is called, by M. Gaultier, Tunica Albida Superficialis, from its whiteness and superficial situation; in many animals it is very distinct, in the negro somewhat so, but in the white it is not to be seen except under the nails, about the hair, and under accidental horny excrescences. These observations of M. Gaultier have been verified by M. Dutrochet,§ in experiments upon the texture of the skin of ver- tebrated animals; and are now generally acknowledged by the French anatomists. In negroes, in cutting through the skin ,of * Expts. on Perspiration. London, 1795. f Wister's Anat. vol. i. p. 394. $ Recherches sur la peau, Paris, 1809; in Anat. De L'Homme, par J. Cloquet, pi. cxvii. § Journal de Physique, May, 1819. Journal Complementaire, vol. v. RETE MUCOSUM. 335 the sole of the foot, from heel to toe perpendicularly to the fur- rows, this arrangement is readily recognised;* and when it has become indistinct, it may be improved by immersing the skin for three or four days in lime-water, or a solution of potash or ba- rytes, and afterwards keeping it the same length of time in a so- lution of corrosive sublimate. Blisters also elucidate this point on other parts of the body: the fluids being locally attracted there, infiltrate the rete mucosum, and separate in part its layers, so as to form a vesicle frequently very thick, particularly in fat persons. The scrotum of the negro is also well suited to the exhibition of the rete mucosum, as it is there very distinct, and is univer- sally much thicker and better marked in the negro than in any other race. From its extreme tenuity in the whites its existence in them has by some persons been doubted, but erroneously, as in them also its change of colour, from the influence of the sun, is readily demonstrated. There are in fact few persons, perhaps none, so white, but what a slight tinge of yellow exists in their skins; which may be proved by contrasting them with any per- fectly white surface, as snow, bleached paper, or linen. This slight tinge of yellow is increased to an olive colour by the sun's rays, and, in some instances by a spontaneous deposite; in other cases, it is in certain spots removed, so as to leave a colour al- most perfectly white, or that only of the cutis vera.t When the latter change occurs in the African, it occasions a hideous pie- bald complexion, and the cuticle is readily elevated into blisters, by the irritation of the solar rays. Some persons have an entire deficiency of this pigment on the skin, from birth; the same de- ficiency occurs in the eyes, and hair; they are designated as al- binos. The deficiency of the pigmentum nigrum in the eye, causes it to look red, like that of the white rabbit; and also makes it intolerant of a strong light, as that of noon-day. " In some very remarkable instances the skin becomes entirely black. We have read to the Society of Medicine of the Facul- ty, the history of a woman whose skin became black in the pe- riod of a night, in consequence of a strong moral impression. * J. Cloquet, Anat. De L'Homme, pi. cxvi. fig. 6. ■j- A case of this kind is now in the Philadelphia Alms House, where the ab- sorption of colour has occurred in spots on the hands of a dark complexioned Eu- ropean. June J 5, 1826. 336 INTEGUMENTS. This woman had seen her daughter throw herself out of the win- dow with her two little children; and we have since had occa- sion to see, also, a woman, who, having escaped capital punish- ment, in the revolution, had experienced the same accident. The latter was at the period of menstruation when she learned this news. The menses were immediately suppressed, and from white, which she was, she became black as a negress, which colour con- tinued even to her death. We dissected with care the skin of these two women, and found the coloured portion to be the rete mucosum. We found it sufficiently easy to isolate the epidermis and the dermis, which presented no abnormal coloration. This black colour must be the result of a sanguineous exhalation which operates upon the rete mucosum. " The violet tinge of the skin is, ordinarily, the result of em- barrassed circulation. The skin becomes blue in many very ad- vanced diseases of the heart. The name of Cyanosis, or blue disease, has been given to this colour of the skin, which is falsely attributed to an immediate communication of the auricles by means of the unobliterated foramen ovale. This cause of the cy- anosis is much more rare than is commonly supposed."* The pigment of the rete mucosum would seem, for the fore- going reasons, to be continually undergoing a deposition and ab- sorption. When it has been lost by a blister in an African, it is generally restored in a short time afterwards: the same occurs in their cicatrices, but requires a longer period. The observations of chemists tend to prove that it is formed principally by car- bon. Its apparent use is to defend the skin from the rays of the sun, in illustration of which several ingenious experiments have been executed by Sir Everard Home, t Anatomists generally have rejected the idea of the vascularity of the rete mucosum, yet it would seem to have been injected, on one occasion at least by the late Dr. Baynham, in a leg which was diseased from exostosis; % and there are now in the anatomi- cal cabinet of the University, three preparations by myself, of the fingers of an African, where the colouring matter of the in- * Cours de Medecine Clinique, par Leon Rostan. Paris, 1830. | Philos. Transact. London, 1821. * Meckel speaks familiarly of its being furnished with an innumerable quantity of capillary vessels. Vol. i. p. 470. CUTICLE. 337 jection has been passed from the papillae of the cutis vera into the rete mucosum; and there deposited in dots, indicating the for- mer position of the papillae. SECT. III.—OF THE CUTICLE (cUTlCULA.) The Cuticle or Epidermis, is the most superficial layer of the skin, and takes its wrinkles from the closeness of its application to the true skin. It is a thin, dry pellicle, which cannot be sepa- rated from the cutis by dissection; in consequence of which we have to resort to the alternate application of hot and cold water; to partial putrefaction; or in the living body to vesicatories. The mode of adhesion between the cuticle and the true skin is not precisely understood: the surfaces unquestionably adhere, through the intervention of the rete mucosum, with equal tenacity where there are neither hairs nor sebaceous follicles to pin them toge- ther, as on the palms of the hands and soles of the feet; and when by previous management this union is somewhat softened, they part very much after the manner of two sheets of paper, which had been recently glued and were almost dry. From this it would appear that the adhesion is universal, and not defective at any points. In most parts of the body the cuticle presents itself as a single homogeneal layer, of a thickness uniformly about that of the thinnest Chinese blotting paper. Upon the palms and soles of persons generally, but especially of such as are addicted to heavy labour, and exposed to a continued mechanical irritation of these parts, the cuticle becomes much thickened and laminated, appa- rently from a successive deposite of it on the skin, there. It is transparent, by which the colour of the parts beneath is readily discernible; in the African, however, it is extremely difficult, nay, impossible to clean it wholly of the colouring matter of the rete mucosum; it seems indeed as if it were, according to the opinion of some, impregnated by it. The structure of this body is entirely peculiar; there is no evidence whatever of the existence of ves- sels in it: on the contrary, in inflammations, when the skin becomes of the deepest tinge of red, the epidermis never has its colour changed in the smallest degree; the impression made on it is only Vol. L—43 338 INTEGUMENTS. manifested by its dropping off, while another layer is preparing to take its place. .Dr. W. *v;^ It strengthens the lower part of the, abdornen.t on other occasions a smaller transverse muscle is present, which decussates the larger, and is inserted into the twelfth rib. > * Varieties. If there are eight sternal ribs, then this muscle has an additional costal insertion. It sometimes sends a fasiculus to the fourth rib; and I have seen it ascending over the pectoralis major, to the root of the neck, as occurs in mam- miferous animals. ■J- Varieties. It is frequently defective, but sometimes two, three, or even MUSCLES OF THE ABDOMEN. 391 At the linea semilunaris the tendon of the internal oblique and of the transversalis unite intimately; and just beyond this junction the two laminae are formed, which enclose the rectus muscle. The anterior lamina is one half of the tendon of the internal oblique, which, after passing half an inch or an inch, is joined to the tendon of the external oblique, goes in front of the rectus muscle, and covers it from origin to insertion. The posterior lamina, made by the posterior half of the tendon of the internal oblique, is united already at the linea semilunaris to the tendon of the transversalis: in this manner they pass behind the rectus muscle from the cartilago ensiformis to a line half- way between the umbilicus and the 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, al- most to the linea alba. The term insertion, expresses, very imperfectly, the manner in which the tendons of these broad muscles all terminate in the linea alba from the thorax to the pelvis. It should rather be said, that they coalesce there by a general intertexture of their fibres. The Cremaster, Is commonly attributed exclusively to the internal oblique, as it is said to be a detachment of fibres from it; but it is also formed by fibres from the lower edge of the transversalis mus- cle. The history of its formation is as follows: in the descent of the testicle, the latter has to pass beneath that edge of the transversalis and of the internal oblique which is extended from the outer portion of Poupart's ligament, to the spine and crista of the pubes. As the testicle descends, it comes in contact with a fasciculus of these fibres, and takes it along. This constitutes the Cremaster muscle, which, in adult life, and in a strong mus- cular subject, is seen descending on the outside of the sperma- tic chord, and spreading over the anterior part of the tunica va- ginalis in arches with their convexities downwards, then rising four, are seen on a side. When defective, the rectus or obliquus internus is better developed than usual. 392 MUSCLES. on the inner side of the chord, to be inserted into the spine of the pubes.* It draws up the testicle. Fascia Transversalis Abdominis. The Fascia Transversalis is placed immediately behind the transversus muscle, between it and the peritoneum. An open- ing in it, which permits the spermatic 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 internal ring is rather nearer to the sym- physis pubis than to the spine of the ilium. The space between the internal ring and the external ring, is about eighteen lines in the adult, and is very properly called the Abdominal Canal, from 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 side is formed by the fascia transversa- lis: and above, this canal is overhung by the internal oblique and the transversalis muscles. The spermatic chord, after pe- netrating the fascia transversalis, does not cross, directly at right angles, the inferior edge of the internal oblique and transversa- lis, but it slips under them very obliquely: its inclination being towards the pubes, so that it can be considered as disengaged from the inferior edge of these muscles, only about the middle of the abdominal canal. * Anat. De L'Homme, par Jul. Cloquet. This account, though easily verified in some subjects, and especially in such as are muscular, does not appear to be ap- plicable to all, or, in other words, the arrangement in them is not quite so obvi- ous. It does not agree with Mr. John Hunter's observations on the descent of the testicle; for he always found, while the latter was still in the loins, the cre- master running towards it. Moreover, in the buffalo of America, a testicle of which Dr. It. Harlan, of this city, was obliging enough to furnish me with for dis- section, I found that the cremaster, though remarkably robust and strong, forms none of those nooses or arches with their convexities downwards, but terminates at the testicle in a tendinous and somewhat abrupt manner. Taking all these points into consideration, it may be, that a part of the cremaster is formed after the manner iudicated by Mr. Hunter, and another part after that mentioned by M. Cloquet; or, indeed, cases may occur, presenting exclusively one or the other. MUSCLES OF THE ABDOMEN. 393 The opening in the Fascia Transversalis, or the Internal Ring, is not abrupt and well defined; but the fascia, where it transmits the spermatic chord, is reflected by a thin process, and terminates insensibly on its cellular substance. At the pos- terior or ventral face of the External Ring, the fascia transver- salis is not in contact with the chord; but that part of the ten- don of the internal oblique and transversalis which is inserted into the crista of the pubes, and forms a sheath for the pyrami- dalis muscle, is placed between them, and secures this opening. The peritoneum covers the posterior face of the fascia trans- versalis, and is thrown into a duplicature or falciform process, passing from near the middle of the crural arch towards the umbilicus. This duplicature depends upon the round ligament of the bladder, which was once the umbilical artery of the foe- tus. It is broader near the pelvis than it is above, has its loose edge turned towards the cavity of the abdomen, and ascends near the pubic margin of the Internal Ring. The effect of its existence is to divide the posterior face of the inguinal region into two shallow fossae; one next to the ilium, and the other next to the pubes. The one next to the ilium contains the be- ginning of the internal abdominal ring, which is frequently marked by a little pouch of peritoneum, going along the sper- matic chord for a few lines. The fossa on the inner or pubic side of the falciform process is just behind the external ring, but separated from it by the fascia transversalis, along with the tendon o£.,the lower part of the internal oblique and of the transversalis1 muscle, where it is inserted into the pubes, and forms the sheath of the pyramidalis. The two fossae indicate the points where inguinal herniae commence; the proper ingui- nal,protrusion begins in the external fossa, and the ventro-in- girm'al(in the internal fossa. 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 ^^nu.ch of the zeal with which the anatomy of hernia has been ^investigated, in latter years, is attributable to him. The fascia transversalis is a thin tendinous membrane, most generally; oc- casionally it is merely condensed cellular membrane. It arises Vol. I.—50 394 MUSCLES. from the internal or abdominal edge of Poupart's ligament, and from the crista of the pubes just behind the insertion of the common tendon of the internal oblique and transversalis mus- cles, and is extended upwards on the posterior face of the trans- versalis muscle to the thorax. At its origin it is attached to the inferior edge of the transversalis and internal oblique, particu- larly the part between the internal ring and the symphysis pubis. It-is also attached to the exterior margin of the rectus abdominis. The internal abdominal ring, or opening in this fascia, marks it out in some measure into two portions, of which 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. Were it not for the important influence of the fascia superfi- cialis abdominis and the fascia transversalis upon hernia, and the consequent necessity of a minute knowledge of them, their description might be much curtailed in considering them in their proper light, to wit; as sheaths of the abdominal muscles; for it is now sufficiently apparent that the first is contiguous to the external oblique, and the second to the transverse muscle. Upon the same principle, fasciae might be made of all the la- minae of cellular substance intermediate to the abdominal mus- cles, but it would be useless. On removing the peritoneum from the iliacus internus mus- cle, the spermatic vessels are seen to descend from the loins to the internal ring, where they are joined by the vas deferens coming from the pelvis. As they engage under the edge of the internal oblique muscle, after penetrating the ring, the cre- master muscle is detached to spread itself over them. The sper- matic chord, thus constructed, passes through the abdominal canal in the manner mentioned, obliquely downwards and in- wards; and, emerging from the external ring, it descends ver- tically, lying rather upon the outer column of the ring than upon its base. On the posterior face of the fascia transversalis, between it and the peritoneum, is the Epigastric Artery. The epigastric arises from the external iliac as the latter is about to go under. the crural arch; it ascends inwardly,along the internal margin of the internal abdominal ring to the exterior margin of the MUSCLES OF THE PARIETES OF THE ABDOMEN. 395 rectus abdominis 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 of its sides, and end by a common trunk in the external iliac vein. The anatomical arrangement of the parts concerned in ingui- nal hernia in the female is the same as in the male, except that the round ligament of the uterus supplies the place of the sper- matic chord, and there is no cremaster muscle. SECT. III.—MUSCLES OF THE UPPER AND POSTERIOR PARIETES OF THE ABDOMEN. These muscles are constituted by a single symmetrical one, and by four pairs: they can only be seen advantageously by removing the abdominal viscera. 1. The Diaphragm, (Diaphragma,) Is a complete, though moveable septum, placed between the thoracic and abdominal cavities; it is extremely concave below and convex above, the concavity being occupied by several of the abdominal viscera. It is in contact above with the peri- cardium and lungs, and below with the liver, spleen, and sto- mach. It is connected with the inferior margin of the thorax on all sides, and has for its centre a silvery tendon, resembling in its outline the heart of a playing card. This cordiform tendon occupies a considerable part of the extent of the diaphragm, has its apex next to the sternum, and its notch towards the spine; and the muscular part of the diaphragm is inserted all around into its circumference. The cordiform tendon is nearly horizontal in the erect pasture, its elevation being on a line with the lowest end of the second bone of the sternum. On each side of this tendon some of the muscular fibres rise so high upwards before they join it, that they are on a horizontal level 396 MUSCLES. with the anterior end of the fourth rib. The fasciculi of mus- cular fibres are, for the most part, convergent from the cir- cumference of the thorax, and are easily separated from one another. In the diaphragm are three remarkable foramina. The first (the Foramen CEsophageum) is in the back of the muscle, be- tween the spine and the notch of the cordiform tendon, a little to the left of the middle line. It gives passage to the oesophagus and the par vagum nerve along with it, and is rather a fissure or a long elliptical foramen made by the separation and reunion of the muscular fibres; for, above and below, at each end of the ellipsis, these fibres decussate one another in columns. To the right of this foramen, and a little above its horizontal level, in the back part of the cordiform tendon, is a very large and pa- tulous foramen for the ascending vena cava, (Foramen Quad- ratum.) Its form is between an irregular quadrilateral figure and a circle; its edges are composed of fasciculi of tendon rounded off, and are not susceptible of displacement, or of al- teration 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, and about three inches from the foramen for the oesophagus, is the third hole, in the dia- phragm, which affords passage to the aorta, (Hiatus Aorticus.) It is just in front of the bodies of the three upper lumbar verte- brae, 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 mus- cular fasciculi arising from them. Through it, besides the aorta, pass the Thoracic Duct and the Great Splanchnic Nerve of both sides. 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 detailed origin of the Diaphragm is as follows. It arises fleshy from the internal face of the upper edge of the Xiphoid Cartilage, from the internal face of the car- tilages of the seventh true, and from the succeeding false ribs, MUSCLES OF THE PARIETES OF THE ABDOMEN. 397 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 cartilaginous termination of the twelfth rib. As the line described includes almost the whole of a circle, and the fibres all converge to the cordiform tendon, they, of course, will pass in different radiated directions, and be of different lengths, which it is unnecessary to specify. Be- tween the sternal and costal portion on each side, there is a triangular fissure filled with fatty cellular tissue, which some- times leaves an opening for hernia. I have seen a case of the kind, in which the transverse part of the colon was the subject of protrusion into the thorax. It is probable that the great dis- placement of the abdominal viscera into the thorax, which some- times occurs, may have a congenital origin in this very fissure, and is subsequently, when the parts are accommodated to their unnatural situation, thought a lusus naturae. The portion de- scribed is called the Greater Muscle of the Diaphfagm. Besides these origins, the diaphragm has several from the ver- tebrae of the loins, constituting 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 verte- bra 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 vertebrae. The second pair of heads is on the outside of the first, and arises tendinous from the interver- tebral ligament, between the second and third vertebrae. The third pair of heads arises tendinous from the upper part of the lateral margins of the second lumber 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 two sides 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 * This origin of the lesser muscle of the diaphragm is given by Albinus, but it is difficult to make out fairly; for the most part it would be much more correct to say that it arises tendinous, from the first, second, and third vertebrae. The heads are generally much smaller on one side, the left, than the other. 398 MUSCLES. and lesser muscles, by a tense ligament, the Ligamentum Ar- cuatum, which passes from the root of the transverse process of the first lumbar vertebra 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 abdominis. Use. In consequence of the muscular fibres of the diaphragm passing in a curved direction from the circumference of the tho- rax to the cordiform tendon; and of those fibres forming a body concave below and convex above, their contraction at the same moment enlarges the cavity of the thorax, and has a tendency to diminish that of the abdomen, which latter is prevented by the yielding of the abdominal muscles. In easy respiration, its contractions and relaxations produce alternately the actions of inspiration and of expiration. Its descent, also assists in the expulsion of fcecal and other matters from the abdomen. By the experiments of Bourdon,* it appears that it only acts a se- condary part in the latter,—that its functions are limited to in- spiration and the associated actions; but that in regard to its power of assisting in the expulsion of the contents of the ab- domen, all that it does is first of all to fill the lungs with air, and then the closure of the glottis prevents the air from being expelled from the lungs. Common observation in parturition shows us, that the expulsive effort of the abdominal muscles does not take place when inspiration is going on, for the former would prevent the latter; but the moment that expiration be- gins, it is arrested by the firm closure of the glottis, and then the abdominal muscles contract advantageously. The Quadratus Lumborum, Is an oblong muscle, arising from the spine of the ilium, at the side of the lumbar vertebrae, by a tendinous and fleshy ori- gin of two or more inches in length. Lying at the side of the lumbar vertebrae, it is inserted into the transverse process of each of them by short tendinous slips: it is also inserted into the lower edge of the last rib near its head, and into the trans- verse process of the last vertebra of the back. * liecherches sur la Respiration et la Circulation. Paris, 1820. MUSCLES OF THE PARIETES OF THE ABDOMEN. 399 It bends the loins to one side, and draws down the last rib. It is covered behind by the tendinous origin of the transver- salis abdominis, which separates it from the sacro lumbalis and. from the longissimus dorsi. It may also be seen very well from behind, in the dissection of the back.* The Psoas Parvus, Arises, fleshy, from the contiguous edges of the last dorsal and of the first lumbar vertebra at their sides, and from the in- tervertebral ligament. It is at the anterior and internal edge of the psoas magnus; has a short belly, and a long tendon by which it is inserted into the linea innominata, about half-way between the spine of the pubes and the junction of this bone with the ilium. The tendon, besides, is expanded into the fas- cia iliaca. Its use seems to be, to draw upwards the sheath of the fe- moral vessels, which is derived from the fascia iliaca, and, con- sequently, to draw upwards the vessels themselves, which pro- bably diminishes the liability to injury from their too great or sudden flexion. This muscle is sometimes wanting. The Psoas Magnus, Arises, fleshy, from the side of the bodies of the last dorsal and of the four upper lumbar vertebrae, and from the transverse processes of all the lumbar vertebrae. It forms an oblong fleshy cushion on the side of the lumbar vertebrae, and constituting the lateral boundary of the inlet to the pelvis, 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 upwards.! • Varieties. Sometimes a broad tendon from it is inserted into the inferior margin of the body of the eleventh vertebra of the back. Sometimes a fascicu- lus of it touches the margin of the eleventh rib, near its head, and above the in- tercostal vessels. f Varieties. Sometimes it is joined by muscular fasciculi from the first, second, and even the third bone of the sacrum. Sometimes, where it borders on the pel- vis, there is a small fasciculus, which continues distinct almost to the trochanter 400 MUSCLES. The Iliacus Internus, Occupies the concavity of the ilium, being on the outside of the psoas magnus. It arises, fleshy, from the transverse pro- cess of the last lumbar vertebra; from the internal margin of the crista of the ilium; from the whole concavity of the latter; from its anterior edge at and above the anterior inferior spinous pro- cess; and from that part of the capsule of the hip joint near the latter process. This muscle terminates in the tendon of the psoas magnus, just above the insertion into the trochanter minor. This and the psoas magnus, from having a common tendon, might with propriety be considered as only one muscle. Their action is the same.* Of the Fascia Iliaca. The Fascia Iliaca is a tendinous membrane, which lies on the iliacus internus and psoas magnus muscles, and is continued into the tendon of the Psoas Parvus. Externally, it is connect- ed 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 pel- vis, 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 pro- cess of the ilium almost to the pubes, and is there continuous with the fascia transversalis abdominis. The external iliac ves- sels are upon this fascia, between it and the peritoneum; and below them the fascia iliaca goes over that part of the pubes which gives origin to the pectineus muscle, and is continuous with the pectineal fascia, or that which covers the pectineus muscle. By introducing the finger or a knife handle into a minor, and then sends its own tendon into the common tendon of the iliacus in- ternus and psoas magnus. * Varieties. Sometimes an additional fasciculus arises below the inferior an- terior spinous process, and descends along the external margin of this muscle. This fasciculus varies somewhat in its size at different points, and is inserted into the linea aspera below the trochanter minor. In very rare cases, the iliacus in- ternus is kept totally distinct from the psoas magnus, from origin to insertion. MUSCLES OF THE TRUNK. 401 cut through the fascia iliaca, its attachment to the crural arch, and its continuity with the fascia pectinea, will be rendered very obvious. The iliac vessels pass beneath the crural arch on the inner margin of the psoas magnus muscle, the vein being nearest, the pubes and the artery at the outer side of the vein. The fascia iliaca being inserted into the crural arch as far as the vein, may indeed be traced to the crista of the pubes; 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 fe- moral hernia commences. This opening is generally occupied by a lymphatic gland, and a lamina of condensed but loosely attached cellular substance, continuous with the Aponeurosis Pelvica. SECT. IV.--MUSCLES ON THE POSTERIOR FACE OF THE TRUNK. The Trapezius or Cucullaris, Is a beautiful broad muscle, immediately under the skin, co- vering the back parts of the neck and thorax, and extending from the bottom of the latter to the top of the former. Its an- terior edge, above, is parallel with the posterior edge of the sterno-cleido-mastoideus. Its posterior edge is joined with that of its fellow, and below, it overlaps in part the latissimus dorsi. It arises from the occipital protuberance, and from eight or ten lines, sometimes more of the superior semicircular ridge of the occiput, by a tendinous membrane. It arises also from the five superior spinous processes of the neck through the inter- vention of the ligamentum nuchae, 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 process, and into all the spine of the scapula. Its fibres having a very extended Vol.!.—51 402 MUSCLES. origin, must of course converge in getting to these insertions; the upper fibres descend, the lower ascend, and the middle are horizontal.* It draws the scapula towards the spine. In the cervical portion of these muscles, formed by the ori- gins of both muscles united, is an elliptical expanse of tendon, lying over the ligamentum nuchae, and extended on each side. The ligamentum nuchae itself, as mentioned elsewhere, is a ver- tical septum of ligamentous matter, extending from the central line of the occipital bone, to the spinous processes of all the vertebrae of the neck. At its upper part, where the spinous processes of the neck are short, this septum is very broad, and divides completely the muscles of the two sides of the neck. The Latissimus Dorsi, Is situated under the skin at the lower part of the back, so as to cover the whole posterior portion of the latter. It arises by a thin tendinous membrane, from the seven inferior spinous processes of the back; and by a thick tendinous membrane from all those of the loins and sacrum. Its origin also extends along the outer inferior margin of the sacrum, and from the posterior third of the spine of the ilium.! Besides which, the latissimus dorsi has from the sides of the three or four inferior false ribs, as many fleshy heads which are connected 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 terminate in a flat, thick tendon, of two inches in breadth, which is inserted into the posterior ridge of the bicipital 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. It is there behind the teres major, but as it advances it winds around the inferior edge of the latter so as to get before it. Afterwards * Varieties. It is sometimes short of the origin described, by from one to four, of the lower spinous processes of the back. Also the lower fasciculus is sometimes disjoined from the rest of the muscle, by a large triangular space. | This origin frequently is tendinous at the back part of the ilium, and fleshy in front. MUSCLES OF THE TRUNK. 403 the tendons of the two adhere closely, but have a bursa between them at their termination. That portion of the tendon of the latissimus which is continuous with the lower edge of its fleshy belly, by a half spiral turn in the latter, becomes uppermost; while the upper portion is by the same arrangement made lowest At the place of its insertion, it is commonly connected to the pectoralis major. The inferior margin of its tendon de- taches a slip to the brachial fascia, and the superior margin another to the smaller tuberosity of the os humeri. It draws the os humeri downwards and backwards.* The thick tendinous membrane coming from the spinous pro- cesses of the loins and back is the fascia lumborum, and is com- mon to the latissimus and several other muscles to be men- tioned. The Serratus Inferior Posticus. The origin of this muscle is inseparably united to that of the ^latissimus dorsi by the fascia lumborum, and comes from the two inferior spinous processes 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 dia- phragm in some respects, but more particularly to the serratus superior posticus. The removal of the trapezius brings into view several mus- cles: the most superficial of which are the rhomboid, which, being two together, look very much like one. The Rhomboideus Minor, Is above the other. It is a narrow muscle which arises by , a thin tendon from the three inferior spines of the neck, and, passing obliquely downwards, is inserted into the base of the scapula opposite the beginning of its spine. * Varieties. Sometimes from its anterior extremity a fleshy or tendinous slip is detached in front of the coraco-brachialis, and is inserted into the posterior face of the tendon of the pectoralis major. The brachial vessels and nerves are liable to compression from this arrangement, which is said to be natural to birds 404 MUSCLES. The Rhomboideus Major, Arises, also, by a thin tendon from the last spine of the neck, and from the four superior of the back, and is inserted into all the base of the scapula below its spine. These muscles draw the scapula upwards and backwards. The Serratus Superior Posticus, Arises by a thin tendon from the three inferior spines of the neck, and the two superior of the back, and is 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. - Between the two serrati is an aponeurotic expansion de- scribed by Rosenmuller, which connects them with each other, and has induced some anatomists to consider them as but one muscle. It is thin and diaphanous, but has the fibrous structure very apparent, and running in a transverse direction from the spinous processes to the angles of the ribs. The superior mar- gin of the latissimus dorsi also runs into this fascia, so as to render its own bounds somewhat undefined. This fascia, along with the ribs and vertebrae, forms that canal in which are con- tained the deep-seated muscles of the back. The Levator Scapulae, Is placed between the posterior edge of the sterno-cleido- mastoideus and the anterior of the trapezius; its lower end is just above the rhomboideus minor. It arises by rounded ten- dons from the three, four, or five, superior transverse processes 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 expresses, it draws the scapula upwards. A good view of this muscle may be ob- tained in the front dissection of the neck.* and moles. Another variety is where a slip runs from this muscle, adheres to the coraco-brachialis, and is inserted tendinous into the coracoid process of the scapula. * Varieties. Sometimes it arises from only two superior transverse processes.; MUSCLES OF THE TRUNK. 405 The Splenitis, Has its inferior extremity beneath the serratus superior pos- ticus, but the principal 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 vertebrae. It is inserted into the back of the mastoid process and into a small part of the adjacent portion of the os occipitis, also into the transverse processes of the two superior cervical vertebrae. It is customary to consider* the part which goes to the head as Splenius Capitis, and the part below as Splenius Colli: the lat- ter, in that case, is said to arise from the third and fourth dor- sal vertebrae. It draws the head and neck backwards. Between the spinous processes of the vertebrae and the angles of the ribs, on either side, the deep fossa is filled up entirely by muscles. Some of them are large and powerful, and the most slriking 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 vertebrae, and extend to the top of the thorax. They arise, tendinous posteriorly, and fleshy, anteriorly, from the pos- terior surface of the sacrum by its external margin and spinous processes: they arise, also, tendinous, from the spinous processes, and fleshy, from the ends of the transverse processes of all the vertebrae of the loins; and principally tendinous from the poste- rior part of the spine of the ilium. The external margin of the belly is fleshy, and all the part nearest to the spine is wholly tendinous below; but, higher up in the loins, it is so only on the surface. The tendon is very strong, and divided into fasciculi, chiefly, near the spinous processes of the lumbar vertebrae. From the under surface of this common belly, two heads, ten- dinous and fleshy, are inserted into the inferior edge of the occasionally its fasciculi are separated from the neck to the scapula; or, a long one is detached towards the spine, thereby presenting a disposition similar to what is met with in the dolphin. * Albinus, loc. cit. 406 MUSCLE?. transverse process of each lumbar vertebra, the smaller near its root, and the larger near its extremity. On a level with the lower rib, and, indeed, somewhat below it, a fissure occurs in the muscle which divides it into two parts. The Longissimus Dorsi is nearest the spine; it is inserted, by small double tendons, proceeding from its internal surface, into the ends of the transverse processes of all the vertebrae 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 beyond their tubercles, except the two inferior. The Sacro Lumbalis is inserted from its outer edge into all the ribs at their angles, by long and thin tendons, which are successively longer, the higher they are inserted. By turning over this muscle towards the ribs, from the other, 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 entirely 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 processes, and is called, from its origin and insertion, the Spinalis Dorsi. The Spinalis Dorsi, Arises tendinous from the spinous processes of the two supe- * Varieties. The origin is uniform, but the insertions vary in their number. Sometimes, a fasciculus commences by a tendinous beginning from the fourth rib, and is inserted into the transverse process of the sixth vertebra of the neck; a fasciculus from the sacro lumbalis joins the fascia extended between the two serrati, or reaches to the splenius colli: the two muscles are sometimes joined closely by an intermediate fasciculus. MUSCLES OF THE TRUNK. 407 rior lumbar, and of the three inferior dorsal vertebrae, and is inserted, tendinous, into the spinous processes of the nine supe- rior dorsal vertebrae, except the first. It tends to keep the spine erect. The Cervicalis Descendens, Is a small muscle placed at the upper portion of the thorax, between the insertions of the sacro lumbalis, and of the longis- simus dorsi, into the upper ribs; it looks, at first, very much like a continuation or appendix of the first, running to the cer- vical vertebrae. This muscle arises from the upper edges of the four superior ribs by Jong tendons: it forms a small belly, which is inserted by three distinct tendons into the transverse processes of the fourth, fifth, and sixth vertebrae of the neck, between the leva- tor scapulae and splenius colli. 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 appearance. It is considered as an appendage to the lon- gissimus 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 trans- verse processes of the five middle cervical vertebrae. It draws the head backwards. The Trachelo Mastoideus, Is at the inner side of the last muscle, in contact with it. It arises by distinct tendinous heads, from the transverse pro- cesses of the three superior vertebrae of the back, and of the five inferior of the neck; and is inserted, by a thin tendon, into the posterior edge of the mastoid process. The dorsal origins are frequently deficient or irregular. It draws the head backwards. 408 MUSCLES. The Complexus, A fine large muscle, is situated at the inner face of the tra- chelo 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 superior dorsal, and the four inferior cervical vertebrae, by their transverse pro- cesses; also, by a fleshy slip from the spinous process of the first dorsal. It is inserted into the inferior part of the os occi- pitis, by the surface between the upper and lower semicircular ridges, on the outside of the vertical ridge which exists in the middle of the bone. It draws the head backwards. The Semi-spinalis Cervicis, Is a muscle which passes obliquely from transverse to spi- nous processes, and is situated between the complexus and the multifidus spinae; the course of its fibres renders it difficult to be distinguished from the latter. It arises from the transverse processes of the six upper ver- tebrae of the back, by tendons which adhere to those of the ad- jacent muscles; and passes up to the neck, to be inserted into the sides of the spinous processes of the five middle cervical vertebrae. It extends the neck obliquely backwards. The Semi-spinalis Dorsi, Is lower down on the spine, and with difficulty distinguished from the multifidus; like the last, it passes from transverse to spinous processes. It lies under the longissimus dorsi, between it and the multifidus. This muscle arises by tendons connected with those of the other muscles, from the transverse processes of the seventh, MUSCLES OF THE TRUNK. 409 eighth, ninth, and tenth dorsal vertebrae; and passes upwards obliquely, to be inserted, tendinous, into the sides of the spi- nous processes of the two lower cervical, and of the five upper dorsal vertebrae. It draws the spine obliquely backwards. The Multifidus Spinas, 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 pos- terior surface, also to the back part of the spine of the ilium. It there forms a belly, of sufficient magnitude to fill up much of the cavity between the spines of the sacrum and the poste- rior part of the ilium. It arises also from the roots of the ob- lique and transverse processes of all the vertebrae of the loins, of the back, and of the four inferior of the neck. The multifidus is inserted, tendinous and fleshy, into the roots and sides of the spinous processes of all the vertebrae of the loins, of the back, and of the five inferior of the neck. This muscle consists of a great number of small bellies, which are parallel to each other, and each of which arises from a trans- verse or oblique process, and goes 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 vertebrae, and be- tween the two latter, there are on either side four small mus- cles, 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, tendinous and fleshy, from the extremity of the spi- nous process of the dentata, and is inserted into the inferior transverse or semicircular ridge of the os occipitis, and into a part of the contiguous surface of bone. Vol. I__52 410 MUSCLES. Its shape is pyramidal, the apex being below. It turns the head, and also draws it backwards. The Rectus Capitis Posticus Minor, Is at the internal edge of the first It arises, tendinous, from the tubercle on the back part of the first vertebra, and is insert- ed into the internal end of the inferior transverse or semicircu- lar ridge of the os occipitis, and into a part of the surface be- tween 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 ver- tebra, and is inserted into the outer end of the inferior semicir- cular ridge of the os occipitis, behind the posterior part of the mastoid process, and beneath the splenius 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 Inter-spinales, Are small short muscles, placed between the spinous processes of contiguous vertebrae. In the neck they are double, in con- sequence of its spinous 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 TRUNK. ' 411 The Inter-transversarii, Are also short muscles, placed in a similar manner, between the transverse processes of the vertebrae. In the neck they are double, in the back they are small, tendinous, and not well marked; and in the loins they are single and well seen. They draw the transverse processes together, and will, of course, bend the spine to one side. The Levatores Costarum, Are small muscles concealed by the sacro lumbalis and lon- gissimus dorsi, and pass from the transverse process of the last cervical and of the eleven superior dorsal vertebrae, to the up- per edges of the ribs. They are twelve on either side of the spine, are tendinous in their origins and insertions, with inter- mediate muscular bellies. The upper ones are small and thin. They increase in mag- nitude 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 occa- sionally to the third. These slips are called Levatores Costa- rum Longiores. The others, which descend from the trans- verse process to the rib next below, are called Levatores Cos- tarum Breviores. i These muscles are parallel in their obliquity, with the ex- ternal intercostals, and are not very obviously separated from them. They perform the same service, that of elevating the ribs. 412 MUSCLES. CHAPTER III. OF THE FASCIA AND MUSCLES OF THE UPPER EXTREMITIES. SECT. I.--FASCIA. The muscles of each upper extremity are invested by an apo- neurotic membrane called the Fascia Brachialis, which extends from the shoulder to the hand. It begins at the base and spine of the scapula, the margin of the acromion process, the acromial extremity of the clavicle, and from the cellular membrane in the arm-pit, and extends itself over all the muscles of the dor- sum of the scapula, and over the deltoid muscle. The tendons of the latissimus dorsi and pectoralis major, each send off from their margins an expansion which is lost in it. Below the spine of the. scapula it is strong and well marked, but on the deltoid muscle, as well as on the muscles of the arm, its desmoid cha- racter is by no means so well developed, though it still retains the appearance of a distinct membrane, and can be raised up as such from the muscles. On the fore arm its ligamentous appearance is well preserved, and extends from the elbow to the wrist in- clusively. Its longitudinal fibres there are well secured by transverse ones. Above the condyles of the os humeri, the Fascia Brachialis sends down to the bone a strong tendinous partition to each ridge, and which runs the length of the latter from its upper end to the condyle. These processes separate the muscles on the back of the arm from such as are on the front of it, and are sometimes called the ligamentum inter-musculare internum and externum. They afford origin to many muscular fibres. At the bend of the elbow, the fascia brachialis is joined by a fasciculus of tendinous matter from the ulnar margin of the tendon of the biceps flexor cubiti, and which, in the contraction of the mus- cle, will keep it tense. At the lower extremity of the fore arm, the transverse fibres, after diminishing sensibly, become more numerous, and by their FASCIA. 413 attachments to the several ridges on the back of the radius and of the ulna, form the Ligamentum Carpi Dorsale. This liga- ment is extended from the styloid or outer margin of the radius, transversely to the styloid or inner margin of the ulna, to the pisiform bone, and to the fifth metacarpal. It consists, in some measure, of two portions: of which the superior is the smaller and thinner, has its fibres descending from the radius to the ulna, and is crossed, in part, by the fibres of the inferior or greater portion. As this ligament adheres, with great strength, to the ridges on the back of the bones of the fore arm, six trochlea? for the tendons of the extensor muscles are thus formed. The first, or that next to the styloid process of the radius, contains the tendons of the two first extensors of the thumb. The second is larger, and transmits the tendons of the two radial extensors of the carpus. The third is small and oblique, for the tendon of the third extensor of the thumb. The fourth is the largest, and is for the tendons of the extensor communis of the fingers. The fifth is between the radius and the head of the ulna, and is for the tendon of the extensor communis which goes to the little finger. The sixth is on the back of the ulna, and is for the ten- don of the extensor carpi ulnaris. The inferior margin of this dorsal ligament of the wrist does not terminate abruptly, but resuming its fascia-like character, is continued over the back of the wrist, and over that of the hand to the fingers. In this progress it furnishes an envelope to the extensor tendons, and is very much blended with the oblique fasciculi, by which they communicate with each other. The Fascia Brachialis affords origin, in part, to the muscles on the dorsum of the scapula below its spine; on the arm it is not so intimately connected with the muscles, but on the fore arm they again begin to arise, in part, from it. In its whole course partitions, constituting the sheaths of the muscles, and which consist, for the most part, of common cellular and adipose membrane, go from it down to the-periosteum and interosseous ligament It adheres very tightly to the ulna, from the ole- cranon to the styloid process. On its cutaneous surface are found all the superficial veins, nerves, and lymphatics of the arm. Bichat considers this membrane as the best example of 414 MUSCLES. the continuity of ligamentous with cellular tissue, and conse- quently of the affinity of the two. The flexor tendons of the hand and fingers are held down, by the Ligamentum Carpi Volare or the Anterior Annular Ligament of the Wrist. It is a very strong fasciculus of liga- mentous fibres, which subtends the concavity of the carpal bones in front, and converts it into the large oval foramen which con- tains the tendons. It is attached by one end at the ulnar side of the wrist, to the hook-like process of the unciforme; to the cuneiforme; and to the pisiforme. Its fibres go straightly across the wrist to be attached by their other extremities to the radial end of the trapezium, and of the scaphoides. Its fibres may be readily distinguished from the fascia brachialis by their uni- formly transverse course; by their whiteness; by their increased thickness; and by their great strength and unyielding nature. Yet the superior margin of this ligament is partially continuous with the fascia brachialis, and the inferior margin with the apo- neurosis palmaris. Several of the little muscles of the hand arise from its front surface, while the posterior is in contact with the flexor tendons. The Aponeurosis Palmaris is placed just below the skin, and covers the middle of the palm of the hand. It is triangular, and has its apex above, where it arises from the inferior margin of the volar or anterior annular ligament of the wrist, and from the tendon of the palmaris longus; it spreads out in its descent, and reaches the lower ends of the metacarpal bones, where it is divided into four portions. Each of these portions bifurcates and passes to the head of its appropriate metacarpal bone, to be fixed to it just in advance of the inferior palmar ligaments. The vacuity of the bifurcation permits the flexor tendons to pass on to the finger, and its branches are held together by transverse and reticulated fibres, the interstices of which are filled with fat." The lateral margins of this aponeurosis send off a thin membrane, for the purpose of covering the muscles of the thumb and of the little finger; or, in other words, the thenar and the hypothenar eminences in the palm of the hand. FASCIA. 415 SECT. II.— OF THE MUSCLES OF THE SHOULDER. The Deltoides, Is a muscle which is extended over the top of the shoulder joint, and forms there the subcutaneous cushion of flesh which protects and gives rotundity to the articulation. It arises from the inferior edge of the whole spine of the scapula, from the circumference of the acromion process, and from the exterior third of the clavicle. Its origin, for the most part, is tendinous and fleshy, mixed, but at its posterior part it is entirely tendi- nous. It is inserted,' by a tendinous point, into the triangular rough surface on the outer side of the os humeri near its middle. Its general configuration is triangular, and when spread out, its upper margin is much more extensive than one would suppose, as it is opposed to the entire insertion of the trapezius. Its fibres do not converge regularly to its insertion like the radii of a circle, but the whole muscle is divided into several parts; the interposition of inter-muscular tendons into which, affecting the course of the fibres, makes several portions of the deltoid look penniform, and others like smaller deltoids introduced into the larger. The deltoid covers the insertion of the pectoralis major, latis- simus 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 extensor and the biceps flexor, and above the origin of the brachialis internus.* It raises the os humeri. Between the superior edge of the deltoid, the acromion pro- cess, and the subjacent tendons on the top of the articulation, there is a large Bursa Mucosa, which is sometimes partitioned off into two. * Varieties. Sometimes a fasciculus arises, between the infra-spinatus, and the teres major, or from the inferior costa of the scapula, and joins itself to the deltoides. 416 MUSCLES. The Supra-Spinal us Scapulae, . Arises, fleshy, from the whole fossa supra-spinata, which it fills up, and from its margins. Forwards it terminates in a thick robust tendon closely connected with the capsular liga- ment of the joint, and which passes under thejugum formed by the articulation of the acromion with the clavicle. It is inserted, tendinous, into the inner face of the great tu- berosity of the os humeri. It raises the arm, and turns it outwards. The Infra-Spinatus Scapulae, Arises, fleshy, from all that portion of the dorsum scapulae below its spine, from the spine as far as the cervix, and from the several margins of the fossa infra-spinata. Its fibres pass obliquely to a middle tendon, which adheres closely to the capsular ligament, and goes under the projection of the acro- mion. This tendon is inserted into the middle facet of the greater tuberosity of the os humeri. The infra-spinatus rolls the os humeri outwards and back- wards. There is a bursa between its tendon and the scapula. The Teres Minor, Is situated at the inferior margin of the infra-spinatus, in the fossa of the inferjpr costa scapulae, and looks very much like a part of the infra-spinatus, to which it occasionally adheres so closely as to be separated with difficulty. It arises, fleshy, from the whole of the fossa, and the margins of the inferior costa, in the space from the cervix of the bone to within an inch or so of its angle. It is inserted, tendinous and fleshy, into the outer facet of the great tuberosity of the os humeri, just below the infra-spi- natus. It draws the os humeri downwards and backwards, and ro- tates it outwards. MUSCLES OF THE ARM. 417 The Teres Major, Is situated at the inferior edge of the teres minor. It arises, fleshy, from the posterior surface of the angle of the scapula, and from a small part of its inferior costa; the interstices between it and the teres minor are considerable. It is inserted, by a broad tendon, into the internal ridge of the groove of the os humeri, along with the tendon of the latis- simus dorsi. Their tendons, at first, are closely united, but af- terwards there is an intermediate cavity lubricated with synovia. The tendon of the latissimus dorsi is anterior, and the lower edge of the teres extends farther down the arm than it. It rolls the humerus inwards, and draws it downwards and backwards. The Subscapulars, Occupies all the thoracic surface of the scapula, being between it and the serratus major. It arises, fleshy, from the whole base, superior and inferior costa, and costal surface of the scapula; it is divided into several columns, which look somewhat like dis- tinct muscles, but they all terminate in a thick robust tendon that adheres to the inferior surface of the capsular ligament This tendon is inserted into the lesser tubercle of the os hu- meri. The subscapularis rolls the bone inwards and draws it down- wards. Between it and the neck of the scapula, there is a bursa, which, as mentioned, communicates with the articula- tion. SECT. III.—OF THE MUSCLES OF THE ARM. The Biceps Flexor Cubiti, This muscle is situated immediately beneath the integuments, and forms the swell so obvious in the middle front part of the arm. It arises by two heads. The first, called the long, is a round tendon which comes from the superior extremity of the glenoid cavity of the scapula, passes through the shoulder joint Vol. I.—53 «, 41S MUSCLBS. and through the groove of the os humeri; the second head arises tendinous from the extremity of the coracoid process of the sca- pula, in company with the coraco-brachialis muscle. The fleshy bellies in which these tendons terminate, unite with each other, several inches below the shoulder joint, to form a common mus- cle. At first, they are only connected by loose cellular sub- stance; but, about half-way down the arm, they are inseparably united. The biceps terminates below in a flattened oval tendon, which passes in front of the elbow joint, to be inserted into the poste- rior 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 the aponeurosis 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 ligamant, and then between the tendons of the latissimus dorsi and pectoralis ma- jor, where it is bound down by strong ligamentous fibres. The tendon below is superficial, and may be easily felt by flexing the fore arm, but its insertion dips down between the pronator teres and supinator radii longus. This muscle flexes the fore arm.* The Coraco-Brachialis, Is situated on 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 facet of the point of the coracoid process of the scapula, in common with the short head of the biceps muscle. It is inserted, tendinous and fleshy, into the internal side of the middle of the os humeri, by a rough ridge, just below the * Varieties. Sometimes the division of the muscle is continued to the elbow; sometimes there is a third head coming either from the internal face of the os humeri, or from the brachialis internusi very rarely, the number of heads has been multiplied to five, thereby making-a close approximation to the arrangement in birds. This muscle is very liable to anomalies. MUSCLES OF THE ARM. 419 tendons of the latissimus dorsi and teres major, and in front of the brachialis externus. The lower end of this muscle is at- tached to the inter-muscular ligament of the internal side of the os humeri, which separates the brachialis internus from the third head of the triceps. This muscle draws the afm upwards and forwards.* The Brachialis Internus, Is situated immediately beneath the biceps, and is concealed by it, excepting its outer edge. It has a bifurcated fleshy ori- gin from the middle front face of the os humeri on each side of the insertion of the deltoid, and its origin is continued fleshy from this point downwards, from the whole front of the bone to within a very small distance of its articular surface. It is inserted, by a strong short tendon, into the rough surface at the root of the coronoid process of the ulna. A bursa some- times exists between the tendon of the brachialis internus, that of the biceps, the supinator brevis, and the elbow joint. 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 pro- nator teres and the supinator longus.t The Triceps Extensor Cubiti, or Brachii, 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, between the teres major and the * Varieties. This muscle being generally penetrated by the musculocuta- neous nerve, the perforation thus made sometimes exists as a fissure, extending the length of the lower half of the muscle; on other occasions the fissure is so long as to divide the muscle completely into two. \ f Varieties. Sometimes, at its external margin, there exists a smaller brachia- lis internus muscle, which arises from about the same point of the humerus, and is inserted into the same part of the cubitus. Sometimes it detaches a fasciculus which joins the biceps muscle. Sometimes its posterior part is distinct from the anterior. Sometimes a fasciculus of it runs along the supinator longus of the fore arm.- 420 MUSCLES. minor muscles, from a rough ridge on the inferior edge of the cervix scapulae- The second, called the Brevis, arises by a sharp, tendinous, and fleshy beginning, from a slight ridge on the outer back part, of the os humeri, just below its head. The third head, called Brachialis 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 separated from the muscles in front of the arm by the external and internal inter-muscular ligaments, which arise near the middle of the os humeri, and run to the condyles respec- tively. The whole back of the os humeri, as well as the pos- terior surface of these inter-muscular septa, is occupied by the origin of the triceps. The muscular fibres run in various direc- tions, 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 the ridge leading down the ulna on its radial side. The bellies of the triceps unite above the middle of the os humeri, but the interstices be- tween them may be observed much lower down. There is a bursa between the tendon and the olecranon process; besides which, there is sometimes another on each side of the first. The triceps extends the fore arm. The Anconeus, Is a small triangular muscle, just beneath the skin, at the outer posterior part of the elbow joint. It arises tendinous from the posterior lower part of the external condyle of the os humeri, adheres to the capsular ligament of the joint, and is partly co- vered by the tendon of the triceps. It is inserted, fleshy and thin, into the ridge leading from the olecranon, on the outer part of the upper end of the ulna; and into the triangular depression found there, so as to fill it up. It extends the fore arm. SECT. IV.—OF THE MUSCLES OF THE FORE ARM. There are eight muscles on the front of the fore arm, some MUSCLES OF THE FORE ARM. 421 of which are superficial, and others deep-seated. They, for the most part, are either directly or indirectly flexors of the fore arm and hand, and in their origin adhere very much by the ten- dinous partitions, called Inter-muscular Ligaments. 1. The Pronator Radii Teres, Is just beneath the fascia of the fore arm, and forms the ra- dial 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 internal edge of the brachialis internus muscle, and is inserted, tendinous and fleshy, into the external back part of the radius, just below the insertion of the supinator radii brevis, occupying about two inches of the middle of the bone. It rolls the hand inwards.* 2. The Flexor Manus vel Carpi Radialis, Is placed at the ulnar side of the last muscle, and is also su- perficial. It arises, by a narrow tendon, from the lower front part of the internal condyle of the humerus, fleshy from the in- ter-muscular ligaments, fascia, and from the upper part of the ulna. It forms a thick fleshy belly, terminating below in a ten- don, which passes under the anterior annular ligament of the wrist, and runs through a groove in the os trapezium. It is inserted, tendinous, into the base of the metacarpal bone of the fore finger, in front. There is a bursa between the lower extremity of its tendon and the trapezium; the tendon is there held down by ligamen- tous fibres. It bends the hand, and draws it towards the radius. 3. The Palmaris Longus, Is at the ulnar side of the flexor carpi radialis, and is super- ficial. It is a small short muscle, terminating in a long slen- * Varieties. Sometimes it is double. 422 MUSCLES. der tendon, and arises by a small tendon from the internal con- dyle, and fleshy from the inter-muscular ligament on each of its sides. It is inserted, tendinous, into the upper margin of the liga- mentum carpi annulare anterius near the root of the thumb, and a division of its tendon passes on to the aponeurosis pal- maris. It bends the hand, and makes tense the palmar aponeurosis.* 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 condyle of the •os humeri, fleshy from the upper internal side of the olecranon, and by a tendinous expansion, being a part of the fascia of the fore arm, from the ridge at the internal side of the ulna to with- in three or four inches of the wrist. It is inserted into the upper side of the os pisiforme by a round tendon, which arises early at the radial margin of the muscle, and receives the muscular fibres. Sometimes the ten- don is continued over the os pisiforme, so as to be likewise in- serted into the base of the metacarpal bone of the little finger. There is a loose bursa at the junction of the tendon with the pisiforme. It bends the hand, and draws it towards the ulna. 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 hu- meri. It arises, tendinous and fleshy, from the internal con- dyle of the os humeri, tendinous from the coronoid process of the ulna, and fleshy from the tubercle of the radius; the latter part of its origin being extended, tendinous obliquely, for three or four inches from that line of the radius which is at the lower * Varieties. Sometimes it is deficient in both arms; sometimes the middle part only is fleshy; sometimes the belly goes almost to the wrist. MUSCLES OF THE FORE ARM. 423 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. Four distinct tendons pass from the lower end of the muscle, which commence much above the wrist, pass beneath its ante- rior ligament, and, having reached the palm of the hand, diverge to the several fingers. A tendon is appropriated to each finger, and passes in front of the metacarpal bone to the phalanges, be- ing inserted, after having split into two, into the angles formed by the junction of the cylindrical and flat surfaces of the second phalanx near its middle. 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 fore 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 co- ronoid and the olecranon processes, fleshy from the carpal mar- gin of the base of the coronoid process, from the ulnar portion of the interosseous ligament, and from the front of the upper two-thirds of the ulna. The tendons of this muscle are different from those of the other; they commence in front of it, like a tendinous membrane, which is gradually divided into several fasciculi, adhering to each other by cellular membrane. The fasciculated character of the tendons is still preserved when they go under the ante- rior carpal ligament, and until they begin to disperse as distinct tendons to each of the fingers. Each tendon, going in front of its metacarpal bone and of the corresponding phalanges, gets through the slit in the flexor sub- limis, and is inserted into the front part of the root of the third phalanx of its respective finger. * Varieties. The tendon to the little finger is sometimes wanting, in which case the deficiency is supplied by the tendon of the flexor profundus. Some- times the section of this muscle which belongs to the fore finger, is insulated from the rest of it, by a long fissure, and, moreover, divided by a middle tendon, into two fleshy portions. 424 MUSCLES. It bends the last phalanges of the fingers, and may, by in- creased action, 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 an acute fleshy beginning, from the radius just be- low its tubercle; also fleshy from the middle two-thirds of the front of this bone, and from the radial portion of the interosse- ous ligament. The body of the muscle is joined by a small fleshy slip having a tendinous origin from the internal condyle of the humerus. A tendon is formed early on the ulnar margin of this mus- cle, to which the fibres pass obliquely. The 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. From the inferior end of the fore arm tovthe middle of the first phalanx, the tendon is invested by its appropriate bursa. It bends the last joint of the thumb. The several Flexor tendons, as they pass under the anterior annular ligament of the wrist, are surrounded by the superior Bursa Mucosa. It begins about an inch and a half above the radio-carpal articulation, and extends to the lower margin of the annular ligament. It adheres by its circumference to this liga- ment and to the capsule of the joint: internally, it sends in a considerable number of processes, whereby each tendon is sur- rounded, and connected to the adjoining tendons; while at the same time no restraint is put upon the natural motions of the part. In its texture this bursa resembles a dense and elastic cellular membrane. In addition to this, the flexor tendons, as they pass from the root to the extremity of each finger, are surrounded by a syno- • Varieties. Sometimes a distinct fasciculus comes from the internal condyle to join it; sometimes a fasciculus comes from the flexor longus pollicis, and ter- minating in a tendinous expansion, is inserted into the tendon which the flexor profundus sends to the fore finger. 0 MUSCLES OF THE FORE ARM. 425 vial bursa; which by its secretion continually lubricates them, and permits them to play freely backwards and forwards, ac- cording to the flexions and extensions of the fingers. These mucous or synovial sheaths, begin a little distance above the first joint of the finger, adhere there to both flexor tendons, and extend to about the middle of the last phalanx. They give to the tendons a very polished lubricated surface; are reflected over the anterior flat faces of the phalanges, being separated from them by a small quantity of adipose matter; they are also reflected over the anterior faces of the capsular ligaments, and line the vaginal ligaments. The Vaginal Ligaments of the fingers (Ligamenta Vaginalia) bind down the flexor tendons and keep them applied to the fronts of the phalanges. They are of the same extent from above downwards, with the mucous sheaths just mentioned, and are stretched between the ulnar and the radial margins of the phalanges. The fibres of which they consist pass for the most part transversely, and are of a fibro-cartilaginous character. These fibres diminish in number towards the end of each finger, and are stronger on the fore finger than on any of the others. In front of the metacarpo-phalangial articulations, and the pha- langial articulations, the vaginal ligaments are much thinner than elsewhere, in order to permit the free flexions of the fingers. The structure, indeed, at these points, is strongly marked off by its diminished thickness; and though the course of the fibres is the same from side to side, yet some anatomists have thought it Worth while to designate it, particularly under the name of Annuli Juncturarum Ligamentosi. Within the vaginal ligaments small tendinous fraena arise from the first and second phalanges; they vary in number in different individuals, and run obliquely forwards, some to ter- minate in the flexor profundus tendons, and others in those of the flexor sublimis; they are called Vincula Accessoria, and are covered by a reflection of the synovial sheath. 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 Vol. I.—54 0 426 MUSCLES. about two inches wide, and its fibres run across the fore arm. It arises, fleshy and tendinous, from the ridge at the inner sur- face of the ulna, near its lower extremity, and from the front of the bone. It is inserted into the corresponding front surface of the radius. It rotates the radius inwards.* Of the Muscles on the back of the Fore Arm. These muscles are ten in number. They arise, for the most part, from the external condyle, and the ridge leading to it, and are extensors either of the fore arm, or of the fingers and thumb. Their origins are less blended with each other than those of the flexor muscles; nevertheless, between several of them there are inter-muscular ligaments which connect them. They are super- ficial and deep-seated. 1. The Supinator Radii Longus, Is situated along the radial edge of the fore arm, immediate- ly 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 mus- cle, 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 about the middle of the radius in a flat tendon. It is inserted, by the tendon, into a small, rough ridge, on the outer side of the radius just above its styloid process. It rolls the radius outwards. 2. The Extensor Carpi Radialis Longior, Is situated beneath the former muscle. It arises, tendinous • Varieties. This muscle in some very rare cases does not exist. Sometimes it consists in two layers whose fibres cross each other. In a case noticed in the Pennsylvania Hospital by Dr. J. R. Barton, it consisted in two triangular pieces, the bases of which were reversed. MUSCLES OF THE FORE ARM. 427 and fleshy, from the space of the external ridge of the os hu- meri, between the supinator longus and the external condyle. It forms a short, fleshy belly, which terminates in a flat tendon above the middle of the radius. It is inserted, by this tendon, into the posterior part of the root of the metacarpal bone of the fore finger, near the thumb. The tendon of this muscle is surrounded by a synovial sheath, at the place where it passes the lower end of the radius, under the posterior carpal ligament. Another bursa is found, also, at its insertion; which, on one occasion, I found so much enlarged in a young woman, as to require its extirpation: the operation was fully successful. 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 terminates in a flat tendon about the middle of that bone. Its tendon, becoming rounded, is inserted into the posterior part of the base of the metacarpal bone of the second finger, and has a bursa beneath its insertion, and another at the wrist. It extends the hand.t 4. The Extensor Carpi Ulnaris, Is superficial, and placed principally parallel with the ulna. It arises, tendinous, from the external condyle, fleshy from the inter-muscular ligament, and inside of the fascia. Crossing very obliquely the upper part of the radius and the ulna, it also arises fleshy from the back part of the latter bone. Its fibres • Varieties. Sometimes a small fasciculus is detached from its posterior mar- gin, and has a tendinous insertion into the third metacarpal bone. + Varieties. Sometimes this muscle is so blended with the preceding, as to be in common with it. I 428 MUSCLES. terminate obliquely in a tendon which goes through the groove of the ulna, and is there furnished with a bursa. „ 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 superficial, being placed between the extensor ulnaris and the extensor radialis brevior. It arises, tendinous, from the ex- ternal condyle, and fleshy from the inter-muscular ligament of the contiguous muscles. As it approaches the wrist it sends off four tendons, which pass together through a common groove on the back of the radius. On the back of the hand these tendons diverge, and near the roots of the fingers send cross slips to each other. Each tendon goes to its respective finger, and covers the whole posterior part of it, being spread out into a membrane which adheres to the phalanges from the root of the first to the root of the last. The precise mode of the insertion of these tendons is as follows: on the back of the first phalanx, the la- teral margins of these tendons are joined by the tendons of the lumhricales and interossei; and the tendinous membrane, thus formed, simply adheres by condensed cellular membrane to the whole back of the first phalanx; the middle part of this tendon then passes on to be inserted near the articular margin of the base of the second phalanx; and the two lateral parts of the ten- dinous membrane, after keeping separate for some distance, unite, and are jointly inserted into the back of the base of the third phalanx. The section of this muscle appropriated to the little finger has a distinct appearance, and frequently its tendon goes through a separate fossa in the radius, from which causes it has obtained the name of Auricularis. A bursa invests these tendons at the wrist as they pass through their groove, and is single above; but, in following the course of the tendons, like them it divides * Varieties. Sometimes its tendon is joined, by a small fasciulus, to the ex. tensor tendon of the little finger. t> MUSCLES OF THE FORE ARM. 429 and follows each tendon respectively to the base of the first phalanx. This muscle extends all the joints of the fingers, being the antagonist of the flexors.* 6. The Supinator Radii Brevis, Can only be well seen by detaching the origin of the afore- said 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, tendi- nous 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 its oblique rough ridge, corresponding with the upper margin of the pro- nator teres. At the interstice between the radius and ulna, near the anterior edge of this muscle, a fleshy slip is occasionally seen which passes from the radial side of the coronoid process to the ulnar edge of the radius. This muscle rotates the radius outwards.t 7. The Extensor Ossis Metacarpi Pollicis Manus, Arises, fleshy, from the posterior part of the ulna immedi- ately below the anconeus, from the interosseous ligament, and from the back part of the radius just below the insertion of the supinator brevis. It terminates in a rounded tendon which passes over the tendons of the radial extensors, and through a groove on the styloid side of the lower end of the radius. The tendon is there invested by a bursa. It is inserted, by its tendon, into the base of the metacarpal bone of the thumb, and into the external side of the trapezium. It extends the metacarpal bone of the thumb. J * Varieties. It sometimes sends a double tendon to the little finger, in which case the auricularis is more distinct than usual, and the tendon next to the ulna runs through a distinct trochlea in the posterior carpal ligament. + Varieties. Sometimes the superior part is separated from the inferior; sometimes the muscle is double. $ Varieties. This muscle is sometimes double, and has several other modifi- cations which it is unnecessary to state. 430 MUSCLES. 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 radius, and terminates in a tendon which passes through the 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 ten- don, 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 an extensive fleshy origin, from the back of the ulna above its middle, and from the inte- rosseous ligament, also from the back of the radius; it terminates near the wrist, in a tendon which passes through the 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 transverse tu- bercle, on the back of the base of the second phalanx of the thumb. Its tendon is furnished with one synovial sheath, at the inferior extremity of the radius, which extends to the carpus, and another which is smaller, and is placed upon the carpus and upon the base of the first metacarpal bone. It extends the second phalanx.t The tendons of the two last muscles are much connected with each other, and are spread in the form of a 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 mid- • Varieties. This muscle is sometimes only an appendage of the preceding. Occasionally, its tendon is confounded with that of the succeeding muscle. | Varieties. Sometimes this muscle is completely double. MUSCLES OF THE HAND. 431 die, and from the contiguous part of the interosseous ligament. It terminates in a tendon which goes through the same fossa with the extensor communis; it afterwards is joined about the head of the first phalanx to the tendon of the common extensor belonging to the fore finger. With the tendon of the extensor communis, it is inserted along the back of the fore finger as far as the base of the third phalanx. It extends the fore finger.* SECT. V.--OF THE MUSCLES OF THE HAND. The Palmaris Brevis, Is just below the skin, at the inner side of the palm of the hand. It consists of separate fasciculi unequally divided, and arises from the anterior ligament of the wrist, and from the ul- nar side of the palmar aponeurosis. It is inserted into the skin and fat at the inner margin of the hand, and covers the muscles of the little finger. It contracts the skin of the hand. Beneath the Aponeurosis Palmaris are placed the long 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 ligamentum carpi annulare anterius, and a little beyond its inferior edge. • Varieties. This muscle is subject to many modifications; sometimes it is di- gastric; sometimes it is double, and the second head goes to the middle finger. In the latter case, anatomists have recognised a disposition similar to that of the short extensors of the toes, and also an arrangement corresponding with what occurs in some species of the ape. Asa general rule, it is admitted that the most of those va- rieties in the muscular system, commonly called anomalies, are only indications on the part of nature of the alliance between the structure of man, and that of the lower orders of animals. In this point of view, they are both instructive and amusing, and are well deserving of attention. 432 MUSCLES. They terminate in little flat tendons, which run along the outer orradialedgeof the fingers, and are inserted respectively into the tendinous expansion of the extensor communis 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 trapezium and scaphoides. It is inserted, tendinous, into the outer side of the base of the first phalanx of the thumb, and into the tendinous membrane derived from the extensors on its back part. It draws the thumb from the fore fingers. This muscle is next to the skin. 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 an- nular ligament. " It is inserted, tendinous and fleshy, into the radial edge of 4 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 side of the oppo- nens pollicis. A groove is formed in it by the tendon 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 sur- face of the annular ligament, and is inserted into the outer sesa- * Varieties. Sometimes one is deficient; sometimes one or more is double, in which case the supernumerary goes to the ulnar edge of the adjoining finger. MUSCLES OF THE HAND. 433 moid bone; the sesamoid bone, like a patella, being connected to the first phalanx of the thumb by a 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 con- nected, by ligament, to the first phalanx. The short flexor, as its name implies, bends the first phalanx of the thumb- 4. The Adductor Pollicis Manus, Lies in the palm of the hand, beneath the lumhricales and the tendons of the flexor sublimis and profundus. It arises, fleshy, from the ulnar edge of the metacarpal bone of the mid- dle finger, between its base and head, and it is inserted, tendi- nous, into the inner part of the hase of the first phalanx of the thumb, just above the sesamoid bone. It pulls the thumb towards the fingers. The Abductor Indicis Manus, Is on the radial edge of the hand, between the metacarpal bones of the fore finger and thumb, and is just beneath the skin. It arises tendinous from the trapezium, and fleshy from the ul- nar edge of the metacarpal bone of the thumb, between its base and head. Being placed along the side of the metacarpal bone of the fore finger, it is inserted, by a short tendon, into the radial side of the first phalanx. It draws the fore finger from the others. There are three muscles constituting the ball of the ulnar side of the hand, or of the little finger. 1. The Abductor Minimi Digili Manus, Is the most superficial. It arises, fleshy, from the protube- Vol. I.—55 434 MUSCLES. ranee on the internal side of the os pisiforme, and from the con- tiguous part of the annular ligament. It is inserted, tendinous, into the ulnar side of the first pha- lanx of the little finger, and into the tendinous membrane which covers its back part. It draws the little finger from the rest. 2. The Flexor Parvus Minimi Digiti Manus, Is beneath the abductor. It arises, fleshy, from the unciform process of the os unciforme, and from the contiguous 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 meta- carpal bone. It arises, fleshy, from the unciform process of the os unciforme; and from the contiguous part of the annular liga- ment 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 towards the wrist, and thereby deepens the hollow of the hand. The Interosseous Muscles fill up the interstices of the meta- carpal bones; they are seven in number, four on the palm, and three on the back of the hand. The back ones arise by double heads from the contiguous sides of two metacarpal bones; the inner ones have a single head, which comes only from the me- tacarpal bone of the finger which the interosseous muscle is in- tended to serve. As a general description, they all may be said * Varieties. Sometimes it is wanting, in which case the preceding is more de- veloped than usual. MUSCLES OF THE HAND. 435 to arise, fleshy and tendinous, from the base and sides of the me- tacarpal bones, and to be inserted, tendinous, into the sides of the first phalanges, and into the tendinous membrane on the back of the fingers, derived from the tendons of the extensor commu- nis. The four first must be looked for on the palm, the three others on the back of the hand. 1. The Prior Indicis, Is along the radial side of the first digital metacarpal bone, and arises from the base and side of the same. It is inserted, tendinous, into the radial side of the first pha- lanx. It draws the fore finger towards the thumb. 2. The Posterior Indicis, Is at the ulnar side of the first digital metacarpal bone. It arises from the base and ulnar side of the same bone, and is in- serted, tendinous, into the ulnar side of the first phalanx of the fore finger. It draws the fore finger towards the others. 3. The Prior Annularis, Is at the radial side of the metacarpal bone of the third or ring finger. It arises from the base and radial side of the said bone. It is inserted, tendinous, into the radial side of the first pha- lanx 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 fin- ger, and arises from the radial side and base of said bone. It is inserted, tendinous, into the radial side of the first pha- lanx of the same finger. 436 MUSCLES. 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 bone of the fore and of the mid- dle finger. It arises from the opposed roots and sides of these bones. It is inserted, tendinous, into the radial side of the first pha- lanx of the middle finger. It draws the middle finger towards the thumb. 6. The Posterior Medii, Is between the metacarpal bone of the middle and of the ring finger. It arises from the opposite sides and roots of these bones. It is inserted, tendinous, into the ulnar side of the first pha- lanx of the middle finger. It draws the middle finger towards the little. 7. The Posterior Annularis, '• Is between the metacarpal bones of the ring and little finger. It arises from the opposed sides and roots of these metacarpal bones. It is inserted, tendinous, into the ulnar side of the first pha- lanx of the ring finger. It draws the ring towards the little finger. FASCIA. 437 CHAPTER IV. OF THE FASCLE AND MUSCLES OF THE LOWER EXTREMITIES. SECT. I.--OF THE FASCL2E. The muscles of the lower extremity, from the pelvis to the foot inclusively, are invested by a strong aponeurotic mem- brane, placed immediately beneath the skin or common inte- guments. Its external face is in contact with the superficial nerves and blood vessels, and the internal face with the mus- cles. Though it is absolutely continuous from one end to the other, it will be useful, for study, to divide it into three parts; the one covering the thigh, the second covering the leg, and the third covering the foot; as each of them presents certain points of arrangement, which could not be very conveniently introduced into a general description. 1. The aponeurosis of the thigh (Fascia Lata Femoris) begins posteriorly, from the upper part of the gluteus maximus mus- cle, by a very gradual conversion of the cellular membrane of the part into desmoid substance; it also begins in the way of cellular substance from the margins of the sacrum and os coc- cygis. The character here is seldom clearly aponeurotic till it gets on a level with the tendon of the gluteus magnus, fro* which emanate a great many of its fibres. Externally, it arises from the whole length of the crista of the ilium, is there stri- kingly aponeurotic, and is closely adherent to the gluteus me- dius muscle, many of whose fibres arise from it. It also arises from the body and rami of the pubes, and from the tuber and ramus of the ischium. Its attachment at the latter is not very strong, neither is its character so well marked. It is there, in some measure, continuous with the perineal fascia. In front, it adheres very closely to the inferior margin of the tendon of the external oblique muscle, so as to be almost continuous with 438 MUSCLES. it, from the anterior superior spinous process of the ilium to the pubes. From these several connexions at the pelvis, the fascia femo- ris descends in enveloping the muscles of the thigh, and then forms other strong attachments about the knee, to the condyles of the os femoris and to the head of the tibia. In front, it ad- heres very closely to, and is almost blended into the common tendon of the extensor muscles; it adheres also to the inferior margins of the two vasti, and is one and the same with the membranous expansion going from them to the head of the ti- bia, and answering the purpose of capsular ligament to the ar- ticulation of the knee, on each side of the patella, as far back as the lateral ligaments. Behind, it covers up the fat in the ham, and is continued into the fascia of the leg. The fascia femoris, almost every where, consists in a fibrous texture, which is sufficiently evident, but the fibres pass in very various directions. At many places, particularly on the inter- nal side of the thigh, there are oblique fibres spread upon a la- mina which is not fibrous. On the outside of the thigh, the fascia consists principally in longitudinal fibres held together by transverse ones; and when its interior surface is examined, many oblique fibres are also found there. It is very thick and strong externally, thinner behind, and still weaker internally, where cellular substance seems to predominate in its composi- tion. It is pierced at several points with small round holes for the passing of blood vessels and of the cutaneous nerves. From the interior surface of the Fascia Femoris, partitions pass off, which separate the muscles of the thigh from each other, and form sheaths for them. Some of these processes are merely cellular substance; others have a more distinct desmoid character. Externally, as it passes from the gluteus medius to the groin, it separates into two laminae, which receive between them the tensor vaginae femoris, and then reunite. The sarto- rius muscle, in almost its whole length, is also enclosed between two laminae. At the origin of this muscle, the posterior lami- na passes on to the iliacus internus, and psoas magnus muscles, and then to the pectineus, to become the pectineal fascia, in all of which distance it is continuous with the iliac fascia of the pelvis; but the anterior lamina of the fascia at this place has its. FASCIA. 439 upper margin continuous with Poupart's ligament; and this la- mina terminates in a point or angle, which is turned inward to the crista of the pubes, and ends by an insertion into it immedi- ately exterior to Gimbernat's ligament, and in the same line with it This point, from the part which it acts in femoral hernia, has been studied with particular attention, and goes un- der the name of Hey's, or the Femoral Ligament. The Pectineal fascia is placed behind the femoral vessels, but the sartorial fascia is before them.* The latter terminates on its pubic side, in a crescentic or lunated edge of one and a half or two inches in length, the concavity of which is towards the penis.t Hey's ligament is the superior extremity of the cres- cent; the inferior end can scarcely be considered to have a de- finite boundary, but is continuous with the adjacent part of the pectineal fascia. The place of continuity is covered by the sa- phena vein, which being between the skin and the fascia lata, dips there into the femoral vein which is under the crescentic edge. The femoral vessels reposing in their sheaths, are then placed between these laminae of the fascia femoris. The vein is only partially covered by the lunated edge, while the artery, which is on the iliac side of the vein, is completely concealed. By keeping the leg extended, and turning the toes of the subject inwards or outwards, it will be seen that the crescentic edge and the tendon of the external oblique exercise a mutual ten- sion. Beneath Poupart's ligament, at the inner margin of the femoral vein, is the hole called the Femoral Ring, through which the bowel escapes in femoral hernia. This hole is constricted by turning the toes outwards, and relaxed by turning them in- wards; it becomes very much relaxed, if, at the same time, the thigh be drawn upwards. Valuable indications for the mode of replacing a prolapsed bowel are thus obtained. In addition to this arrangement, which is all-important in * By sartorial fascia is merely meant the portion of the fascia lata femoris con- tiguous to the sartorius muscle; and, by pectineal fascia, the part covering the pectineus muscle. f The crescentic edge is not always well defined, for in many cases it is blend- ed insensibly with the sheath of the vessels, so that a defined exhibition of it is rather the result of artificial separation or dissection, than a natural condition. 440 MUSCLES. hernia, the fascia femoris has the following. On the front of the thigh it simply covers the extensor muscles, the partitions between which are cellular substance. On the inner side it dips down to the periosteum between the adductor muscles, but is still cellular. Behind, it covers the ham-string muscles, and sends down to the linea aspera a thick fibrous partition between the vastus externus and the biceps flexor. The superior mar- gin of the gluteus maximus is inserted into this fascia, which from its connexion with the gluteus medius and tensor vaginae femo- ris, causes all these muscles to exercise a mutual influence, as well as to keep tense the fascia itself. On the internal semi-cir- cumference of the thigh it adheres somewhat closely to the mus- cles; but on the external, where the fascia is opposed to the ten- dinous facing of the vastus externus muscle, it is connected by a long, loose, and scattered cellular substance, which scarcely presents an obstacle to the introduction of the finger or any blunt instrument between the two. 2. The Fascia Cruralis, or that of the Leg, though absolutely continuous with that of the thigh, may be described as arising externally, from the head of the fibula and from a prolongation of the biceps flexor cruris; internally, from prolongations of the tendons of the sartorius, the gracilis, and the semi-tendinosus. It, in descending, covers all the superficial muscles of the leg, does not go over the tibia, but adheres to its spine and to its internal angle. It unites below to the annular ligament of the ankle, to the ligamentous sheath of the peroneal muscles, and to that on the inner ankle. The fascia cruralis, in the superior half of the leg, assists in giving origin to its muscles in front and externally, but is rather loosely attached to them below. On the back of the leg it is also rather loosely connected to the gastrocnemii. It sends in one aponeurotic partition between the common extensor of the toes and the long peroneus, and another between the latter and the soleus, both of which are inserted into the fibula. It also is insinuated, between the soleus and the flexor muscles next to the bones. This prolongation is strong and fibrous, penetrates between these flexor muscles, dips down to the tibia and fibula, and is lost insensibly just below the fascia of the popliteus mus- FASCIA. 441 cle. This last fascia may also be considered one of the ema- nations from the fascia cruralis. The fascia cruralis is not so strong as the femoral, yet it has the same compact desmoid texture, and is formed from fibres crossing in various directions. It is thicker in front than be- hind, and is made tense by its connexion with the internal and external ham-string muscles. Of the Ligamentum Annulare of the Ankle Joint. The muscles on the front of the leg have their tendons con- fined at the ankle by this ligament, which may be very properly associated with the description of the crural fascia, owing to the closeness of their connexion. It consists in a fasciculus of ligamentous fibres running across the front of the ankle joint. It is attached by one extremity to the superior face of the greater apophysis of the os calcis, just before the malleolus ex- ternus; is there very strikingly fibrous or ligamentous, and has its small fasciculi separated by fatty matter. It is then directed inwards, and divides into two laminae, one of which goes above the tendons, and the other below them. These laminae, by ad- hering to their respective sides of the tendons, form a loose gut- ter for each of them to play in; the gutters, however,for the ti- bialis anticus and extensor pollicis are not so perfect behind as the others, and are also more loose. The ligament is then fixed by one division to the anterior margin of the malleolus internus, and by another, which is wrapped over the internal face of the foot, into the scaphoides and the internal margin of the fascia plantaris. As the upper margin of this ligament is continuous with the fascia cruralis, so the inferior runs into the fascia on the back of the foot, called aponeurosis dorsalis pedis. Of the Fascia of the Foot.—The fascia cruralis, being strongly attached to the posterior and lower margins of the internal an- kle, its fibres radiate thence to the lower part of the tendo-achil- lis, to the inner side of the os calcis, and to the internal margin of the fascia plantaris. This is the Ligamentum Laciniatum (or Vol. I.—56 442 MUSCLES. plaited ligament) of writers, and conceals the tendons which pass to the sole of the foot, along the sinuosity of the os calcis. The Aponeurosis Dorsalis is continued from the annular liga- ment, over the upper surface of the foot, to the roots of the toes. It is thin, but its fibrous texture is apparent. It is spread over the extensor tendons of the toes and the extensor brevis muscle, and is slightly attached along the internal and the external mar- gin of the foot. The Aponeurosis Plantaris is on the sole of the foot, between its common integuments and the muscles. It is attached be- hind to the tuberosity of the os calcis, and is quickly divided into three portions, which are kept distinct by well marked de- pressions between them. The internal portion lies upon the muscles at the inner side of the foot, the external portion upon the muscles at the outer side, and the middle covers longitudi- nally the central parts of the sole. The two first portions are thin, reticulated, and extended to the roots of the outer and in- ner metatarsal bones, and along the margins of the foot, where they join the fascia dorsalis. The middle portion increases in breadth as it advances, and at the anterior extremity of the me- tatarsus is divided into five slips, one for each metatarsal bone. Each of these slips is subdivided into two, which penetrate up- wards, and fix themselves to their respective side of the head of the metatarsal bone. In the interval left by this bifurcation, pass the flexor tendons, the lumhricales, the vessels and the nerves, to the toe. The plantar aponeurosis, or fascia, affords behind, origin to the superficial muscles of the sole of the foot. It also sends in partitions between them. Its thickness is considerable behind, but continually diminishes as it advances forwards. lis fibrous texture is very well marked, and is much more compact near the heel, where it looks like ligament; the fibres run principal- ly iongitudinally. From its inferior surface many strong fila- ments pass to the skin on the sole of the foot, and contain within their interstices a granulated adeps. MUSCLES OF THE THIGH. 443 SECT. II.—MUSCLES OF THE THIGH. The Tensor Fascia vel Vagina Femoris, Is situated superficially on the anterior outer part of the hip. It arises, tendinous, from the anterior superior spinous process of the ilium; passes downwards and somewhat backwards be- tween two laminae of the fascia femoris, increasing in breadth as it descends; and is inserted fleshy into the fascia femoris, somewhat below the level of the trochanter major. It rotates the foot inwards, and makes the fascia tense. The Sartorius, Is placed superficially on the internal side of the thigh. It arises by a short tendon from the anterior superior spinous pro- cess of the ilium, and passes in a spiral course to the inner side of the thigh and to the back of the internal condyle. It then winds behind the head of the tibia, and advances forwards so as to be inserted into the internal side of the lower part of its tu- bercle by a broad tendon. Its fibres run the whole length of the muscle. Its tendon is continued by a flat slip from its lower margin into the fascia cruralis, by which attachment the muscle is held in its spiral course. It crosses the rectus femoris and vastus in- ternus above, the triceps adductor at the middle of the thigh, and at the lower part of the latter, just above the knee, it is be- tween the tendon of the adductor magnus and that of the gra- cilis. It bends the leg and draws it obliquely inwards.* The Rectus Femoris, Is in front of the thigh bone and just beneath the fascia femo- ris, with the exception of its origin, which is covered by the * Varieties. Sometimes a small fasciculus is detached from its inferior part; sometimes its fibres are interrupted by a middle tendon which adheres closely to the fascia femoris. Meckel reports it as deficient in one case that he met with. In the African I have occasionally seen it unusually broad. 444 MUSCLES. sartorius. 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 of the ilium 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 ligamentum patellae into the tubercle of the tibia. It extends the leg. The Vastus Externus, Is a very large muscle on the outside of the thigh; it arises, tendinous and fleshy, from the upper part of the os femoris, im- mediately below the trochanter major. Its origin commences in front, and passes obliquely around the bone to the linea as- pera. It continues afterwards to arise from 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 mus- cle 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 pointed fleshy origin, in front of the os femoris, just on a level with the trochanter minor, tendinous and fleshy from the whole length of the internal edge of the linea aspera, and from the line leading from it to the internal condyle. 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. MUSCLES OF THE THIGH. 445 The Crurasus, Is almost completely overlapped and concealed by the two vasti, and is immediately 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 sepa- rated by vessels. But the origin of the vastus internus is not so distinguishable, as the fibres of the two muscles run into each other; it is, therefore, necessary, most frequently, to cut through some of their fibres on the internal face of the os femoris, on a level with the trochanter minor. The cruraeus will 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 fe- moris is naked, the breadth of an inch along the whole shaft of the bone, which is very readily seen by turning off the vastus internus. The cruraeus is inserted into the posterior face of the tendon of the rectus below, and into the upper surface of the patella. It also extends the leg. The Ligamentum Patellae is the common 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 inferior edge of the patella, and inserted into the tubercle of the tibia. Between its insertion and the head of the tibia, is a bursa. Besides this, a fascia or tendinous ex- pansion, (Involucrum,) an appurtenance of the fascia femoris, as mentioned before, comes from the inferior ends of these mus- cles, extends itself over the whole of the anterior and lateral parts of the knee joint, and is inserted into the head of the ti- bia and of the fibula. Through this it happens that, even when the patella or its tendon is fractured, some motion or extension may be communicated to the leg from the thigh. In consequence of the common insertion of these four mus- cles, some anatomists describe them as but one, under the name of Quadriceps Femoris.* * Soemmering de Corp. Hum. Fab. 446 MUSCLES. A bursa exists between the lower part of their tendon and the fascia femoris, higher up than the patella; occasionally, one is found still lower down, on the patella. Some unimportant varieties have been observed. The Gracilis, Is a beautiful muscle at the inner margin of the thigh, and lies immediately under the fascia; it extends from the pelvis to the leg. It arises, by a broad thin tendon, from the front of the os pu- bis, just at the lower part of its symphysis, and from its de- scending ramus; the muscle tapers to a point below, and, a little above the knee, terminates in a round tendon, which passes be- hind the internal condyle of the os femoris and the head of the tibia. It then makes a curve forwards and downwards at the internal side of the latter, and is inserted at the lateral and infe- rior part of its tubercle. The tendon at the knee is beneath the tendon of the sarto- rius. This muscle is a flexor of the leg. The Pectinalis, or Pectineus, Is -a short, fleshy muscle, at the inner e'dge of the psoas mag- nus. It arises, fleshy, from the concavity on the upper face of the pubes, between the linea innominata, and the ridge above the obturator foramen, and is inserted, tendinous, into the linea aspera, immediately below the trochanter minor. It draws the thigh inwards and forwards.* Adductors, 1. The Adductor Longus comes, by a rounded, short tendon, from the upper front part of the pubes near its symphysis; it forms a triangular belly which increases in breadth in its de- scent, and is inserted into the middle third of the linea aspera at its inner edge. • Varieties. Sometimes this muscle is split into two by a fissure, in which case the lower portion is the smaller, and has its tendon below connected or joined to the tendon of the other, and its other extremity attached to the upper internal margin of the thyroid foramen. MUSCLES OF THE THIGH. 447 As the subject lies on its back, this muscle is uppermost; its origin is between that of the pectinalis, and of the gracilis; its upper edge is in contact with the lower edge of the pectinalis.* 2. The Addtictor Brevis is the smallest of the three; it is situated beneath the adductor longus and pectinalis, and on the outside of the gracilis. It arises, by a rounded tendon, from the middle front part of the pubes, between 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 li- nea aspera, between the trochanter minor and the upper edge of the adductor longus, by a flat thin tendon.t 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 descending ramus, also from the ascending ramus of the ischium as far as its tuberosity, occupy- ing the whole bony surface between the foramen thyroideum below, and the margin of the bone. It is inserted, fleshy, into the whole length of the linea aspe- ra, and on its internal margin a tendon is gradually 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 in- ternal condyle. The adductor magnus separates the muscles on the anterior from such as are on the posterior part of the thigh; and its in- sertion is closely connected with the origin of the vastus inter- ims, the two surfaces adhering by a short and compact cellular membrane.J The three adductors contribute to the same end, that of draw- ing the thigh inwards. From their common action and very close connexion at their insertions, they are sometimes described * Varieties. Occasionally this muscle is divided into two by a fissure; which is of various lengths. Sometimes it is continued much lower down than usual by means of a small tendon united to that of the adductor magnus. f Varieties. It is also occasionally split, more or less fully, into two muscles by a fissure, which, according to Meckel, establishes a remarkable analogy with apes. i Varieties. It also is occasionally divided into two portions, as in apes, 448 MUSCLES. as one, under the name of Triceps Adductor, and with great propriety. The pectineus muscle is also associated with them so closely in its course and character, that, as Meckel has sug- gested, it ought to be considered as a fourth head to the triceps. The Glutaeus Magnus, Arises, fleshy, from the posterior 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 sa- cro-sciatic 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 sciatic ligament. Its fibres pass obliquely forwards and downwards, and termi- nate in a thick, broad tendon, the upper part of which goes on the outside of the trochanter major, and is very strongly insert- ed into the fascia femoris; while 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 fasci- culi 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 inferior margin laterally, and conceals the origins of the ham-string muscles. There is a very large bursa placed between the tendon of this muscle and the external face of the trochanter major; another of almost equal magnitude, between it, the superior extremity of the vastus externus, and the inferior end of the tensor fasciae fe- moris; and there are two smaller ones between the same tendon and the os femoris, which are placed lower and more poste- riorly. The glutaeus magnus draws the thigh backwards, and assists in keeping the trunk erect. The Glutaeus Medius, Arises from the whole length of the spine of the ilium, ex- cept its posterior part, and from that part of the dorsum of the bone which is between its spine and the semicircular ridge ex- MUSCLES OF THE THIGH. 449 tending from the anterior superior spinous process to the sciatic notch; also from the lunated edge of the os ilium, between the anterior superior and the anterior inferior spinous processes, and from that part of the inner face of the fascia femoris which co- vers it. The anterior superior part of this muscle is not covered by the glutaeus 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 trochanter. It draws the thigh backwards and outwards. A bursa is interposed between the extremity of its tendon and the tendinous insertions gf the small rotator muscles. The Glutaeus Minimus, Arises from that part of the dorsum of the ilium between the semicircular ridge just spoken of, and the margin of the capsu- lar ligament of the hip joint. It is entirely concealed by the glutaeus medius. Its fibres converge and terminate in a round tendon, which is inserted into the anterior superior part of the trochanter major, just within the anterior insertion of the glutaeus medius. It abducts the thigh, and can also rotate the limb inwards. A bursa of small size exists between its tendon and the tro- chanter major. There are several small muscles about the hip joint, the most of which can be seen by the removal of the glutaeus magnus. The Pyriformis, Arises, fleshy and tendinous, within the pelvis, from the an- terior 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 Vol. I.—57 450 MUSCLES. of the trochanter major within the insertion of the glutaeus me- dius. It rotates the limb outwards. Between its tendon and the superior geminus a small bursa exists.* The Gemini, Are two small muscles, closely connected with each other, which are situated lower down on the pelvis than the pyrifor- mis. 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, »nd connected by their conti- guous edges, they are inserted together into the posterior part of the thigh bone at the root of the trochanter major, where the deep pit is. They also rotate the limb outwards.t The Obturator Internus, Is principally situated within the cavity of the pelvis. It arises, fleshy, from all the pelvic margin of the foramen thy- roideum, except where the obturator vessels go out, and from the internal face of the ligamentous 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. Between the tendon of this muscle and the gemini is a long bursa; a second is found where the muscle plays over the is- chium. It rotates the limb outwards. • Varieties. It is sometimes split by the sciatic nerve, and when the latter divides very high up, by one of its portions only. ■J- Varieties. The upper one, occasionally, does not exist, whereby a striking resemblance with apes is established. Sometimes both are wanting. MUSCLES OF THE THIGH. 451 The Quadratus Femoris, Is lower down than the other muscles. It arises, tendinous and fleshy, on the outer side of the ischium, from the ridge which constitutes the exterior boundary of the tuberosity. Its fibres are transverse, and are inserted, fleshy, into the rough ridge of the os femoris, on its back part, which goes from one trochan- ter to the other. It rotates the limb outwards. A bursa exists between it and the trochanter minor.* 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 circumference of the foramen thyroideum, excepting the place where the obturator vessels come out, and from the exterior face of the ligamentous mem- brane stretched across it. The fibres of this muscle converge, pass beneath the capsular ligament of the hip joint adhering to it, and terminate succes- sively in a round tendon, which is inserted into the inferior part of the cavity on the posterior surface of the os femoris, at the root of the trochanter major. The course of the tendon of this muscle is marked on the neck of the thigh bone by a su- perficial fossa. It rotates the thigh outwards. The Biceps Flexor Cruris, Constitutes the outer hamstring, and is situated on the poste- rior outer part of the thigh; it arises by two heads. The first, called the long head, has an origin, in common with the semi- tendinosus, from the upper back part of the tuberosity of the is- * Varieties. Occasionally, this muscle is absent; more rarely it is divided into a great number of fasciculi, amounting in one instance to thirty. 452 MUSCLES. chium, by a short tendinous head, which, in its descent, is changed into a thick fleshy belly. The other, called the short head, arises, by an acute fleshy beginning, from the linea aspera just below the insertion of the glutaeus magnus, and is continued along the lower part of the linea aspera from the ridge leading to the external condyle. A thick tendon is gradually formed on the outside of the muscle, which, descending along the external face of the ex- ternal condyle, is inserted into the superior face of the head of the fibula. A bursa is found between this tendon and the ex- ternal lateral ligament of the knee. This muscle flexes the leg on the thigh.* The Semitendinosus, Is on the inside of the thigh, between the biceps and gracilis; it is superficial, being immediately under the fascia, and arises, in common with the biceps, from the back part of the tuberosi- ty of the ischium; it also adheres, for three or four inches, to the inner edge of the tendon of the long head of the biceps. About four inches above the knee it terminates in a long round tendon, which passes behind the internal condyle and the head of the tibia, and is reflected forwards to be inserted into the side of the tibia, just below its tubercle and very near it, being lower down than the insertion of the tendon of the gracilis. Its insertion is much connected with that of the gra- cilis, and is generally divided into two slips, one above the other. Between its origin, that of the long head of the biceps, and the semimembranosus, there is a bursa; one or more are likewise found between its tendon below, that of the sartorius, of the gracilis, and the internal lateral ligament of the knee. It flexes the leg on the thigh.f * Varieties. Sometimes the short head does not exist, thereby affording an analogy with animals. Sometimes there is a third head, but more delicate, which comes either from the tuber of the ischium or from the long head, and descend- ing along the back of the leg, runs into the tendo-achillis, corresponding there- by with the arrangement of mammiferous animals. -}■ Varieties. Sometimes it is divided into three sections by two transverse ten- dinous lines. MUSCLES OF THE LEG. 453 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 bi- ceps, and below it projects between these two muscles. It is in contact with the posterior surface of the triceps adductor. It arises, by a thick round tendon, from the exterior upper part of the tuberosity of the ischium, which tendon soon becomes flattened, and sends off the muscular fibres obliquely from its exterior edge to a corresponding tendon below. The latter passes behind the internal condyle and the head of the tibia, despatches a thin aponeurotic membrane under the inner head of the gastrocnemius, to cover the posterior part of the capsule of the knee 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 unfa- vourable insertion of this muscle is compensated for by the mul- titude of its fibres, which gives it a great increase of strength. A bursa exists between its tendon above and the quadratus; another exists between its tendinous termination, the internal head of the gastrocnemius, and the capsule of the knee. It flexes the leg on the thigh. SECT. III.--MUSCLES OF THE LEG. These muscles are situated anteriorly, posteriorly, and exter- nally. The Tibialis Anticus, Is situated superficially under the fascia of the leg, at the out- side of the spine of the tibia, and in front of the interosseous li- gament It arises, fleshy, from the head of the tibia, from its outer surface, spine, and from the interosseous ligament to with- in 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 in front below, into which the fleshy fibres run obliquely, and which, passing through a 454 MUSCLES. distinct noose of the annular ligament in front of the malleolus internus, crosses the astragalus and os naviculare, and is insert- ed on the inner side of the sole of the foot into the anterior part of the base of the cuneiforme internum, and into the adjacent part of the metatarsal bone of the great toe. A bursa surrounds the tendon where it passes beneath the annular ligament; another also exists at its lower part. This muscle corresponds with the radial extensors of the arm. It bends the foot, and presents the sole obliquely inwards. The Extensor Longus Digitorum Pedis, Is also superficially placed just under the fascia of the leg and in front of the fibula, being in contact above with the tibialis anticus and below with the extensor proprius pollicis. It arises, tendinous and fleshy, from the outer part of the head of the ti- bia, from the head of the fibula, and almost the whole length of its anterior angle, also from the upper part of the interosseous ligament and the internal face of the fascia of the leg. Its fibres go obliquely downwards and forwards to the tendon which begins not far from its upper end, and descends along its anterior margin. About the middle of the leg the tendon splits into four, which are confined by the annular ligament of the ankle, and then diverging, each is inserted into the base of its respective small toe, and expanded over its back part as far as the last phalanx. When these four tendons first reach the roots of the toes, they expand over the back of the articulation there, and send downwards triangular processes which are attached to the base of the first phalanx, and to the tendinous terminations of the in- terosseous muscles. On the back of the first joint the tendon adheres closely to its synovial membrane, and is somewhat car- tilaginous. At the second joint the tendon splits partially into two, which pass somewhat laterally, and then reunite. The ten- don then adheres again closely to the synovial membrane of the third articulation, and finally terminates in the base of the third phalanx. This muscle extends the toes, but flexes the foot. MUSCLES OF THE LEG. 455 A long bursa is found enveloping the tendons where" they pass beneath the annular ligament of the ankle. 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. It 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 me- tatarsal bone of the little toe, and assists in bending the foot. The Extensor Proprius Pollicis Pedis, Is between the lower parts 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 interosseous ligament, and from the lower part of the tibia. The muscle being half penniform, the fibres run obliquely to a tendon at its fore part, which passes through a particular gut- ter of the annular ligament, and over the astragalus and 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. A bursa invests this tendon where it passes beneath the annular ligament It extends, as its name implies, 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, * Varieties. A partial effort is sometimes manifested to divide it into two mus- cles. 456 MUSCLES. between the external and anterior angles; also, from its external angle to within a short distance of the ankle. A flattened thick tendon, to which the fibres pass obliquely, constitutes the outer face of the muscle. 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 furnished there with a bursa; it then traverses the outer side of the os cal- • cis, where its passage is marked by a superficial sulcus; it then runs through the groove of the os cuboides, where there is ano- ther bursa. Lying deep in the sole of the foot, covered by the calcaneo-cuboid ligament, and next to the tarsal bones, it is in- serted into the base of the internal cuneiform bone, and into the adjacent part of the metatarsal bone of the great toe. It extends the foot and inclines the sole obliquely outwards. It corresponds with tho flexor carpi ulnaris of the fore arm. As the tendon experiences much friction at the ankle, on the , os calcis, and where it winds around the os cuboides, it is not unusual to find in it small sesamoid bones there, especially at the latter place. 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, be- ing covered by the tendon of the peroneus longus, and confined by the same ligamentous noose; passing through the superficial fossa at the outer side of the os calcis, it is inserted into the ex- ternal part of the base of the metatarsal bone of the little toe. It extends the foot, and presents the sole obliquely down- wards. It also corresponds with the flexor carpi ulnaris.* * Varieties. It is sometimes double. MUSCLES OF THE LEG. 457 Triceps Surae. The muscular mass- on the back of the leg,, constituting its calf, is formed by the two following muscles, which, with much reason, may be considered as composing only one. Anatomists, who view them in this latter light, describe, them under the name of Triceps Surae, of which the Gastrocnemius portion has two heads, and the Soleus or Gastrocnemius internus, but one. 1. The Gastrocnemius is the most superficial muscle on the back of the leg, and conceals the other, in consequence of its breadth. It comes 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 leading to the linea aspera; the other head arises, by a broad tendon in the same way, from the external condyle and the ridge above it. A triangular vacancy is left between the heads of the muscle for the passage of the popliteal vessels; the heads then join to- gether, 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* 2. The Soleus is beneath the Gastrocnemius, and 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 origins are separated for the passage of the posterior tibial vessels. The body of this muscle has a great intermixture of tendinous matter in it, and from its lower extremity proceeds another 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 the tendo-achillis is completed, and then inserted into the posterior surface of the Vol. I.—5S 458 MUSCLES. os calcis near its tuberosities. The tendon becomes more round as it descends. These muscles extend the foot, and are all-important in walk- ing. A bursa is between their tendon and the os calcis. 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 con- dyle, passes across the capsular ligament of the joint, and ad- heres 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 part of the soleus and the gastrocnemius. At the place where the tendons of these unite, the tendon of the plantaris emerges from between them, and, running at the inner edge of the tendo-achillis, is inserted into the inside of the os calcis, just before the insertion of the latter. It extends the foot. This muscle is sometimes wanting. It contributes so little to the motions of the foot, and, in other re- spects, is of such doubtful use, that its proper destination is un- certain. In some mammiferous animals it is large and impor- tant; perhaps, therefore, in the human subject, it is one of the links connecting us with animals, of which there are many evi- dences in the muscular system. The Popliteus, Is a triangular muscle on the back of the knee joint. It arises, by a thick round tendon, from a deep depression on the exte- rior face of the external condyle, passes through the capsular ligament, being connected with the external semi-lunar carti- lage; and then forms a fleshy belly which 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 A bursa exists between its origin and the capsular ligament; its tendon is in contact with the synovial membrane of the joint. MUSCLES OF THE LEG. 459 [t bends the leg, and rotates it inwards, when bent. The Flexor Longus Digitorum Pedis Perforans, Is behind the tibia, and at the inner edge of the tibialis pos- ticus. 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 along 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 con- nexion with the fibula at the ankle: the latter origin is, how- ever, frequently deficient, and between this double order of fibres the tibialis posticus passes. The fibres go obliquely into a tendon at the posterior edge of the muscle, which runs in the groove behind the internal malleolus, and is confined there by a strong ligamentous sheath, being placed behind, and within the tendon of the tibialis pos- ticus. 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 base of the last phalanges of the lesser toes, are very near the tarsal bones, and, from per- forating the tendons of the flexor brevis, correspond with the flexor perforans of the hand. A bursa exists where the tendon passes along the tibia and the os calcis; and another is found in the sole of the foot, enveloping this tendon and that of the flexor longus pollicis. A fifth tendon is sometimes observed, which splits and goes to the second bone of the small toe: this occurs when the lat- ter is not supplied from the flexor brevis. This muscle flexes the small toes, and extends the foot. The Flexor Longus Pollicis Pedis, Is a stout muscle formed of oblique fibres, and situated on the back part of the fibula, at the outer side of the tibialis posticus. It arises, by an acute, tendinous and fleshy beginning, from the 460 MUSCLES. posterior flat surface of- the fibula, commencing about three inches from its head, and continuing almost to the ankle. The tendqn of this muscle is large and round; it forms gra- dually, and constitutes a facing to the posterior edge of the mus- ele. It passes through a superficial 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; at the latter place it crosses the tendon of the flexor longus di- gitorum, and gives off to it the branch just mentioned, which goes, principally, to the second toe. This tendon is deeper seated in the foot than the other. The tendon of the flexor longus pollicis is inserted into the last phalanx of the great toe. It bends the great toe, and from its connexion with the others will bend them also. A bursa invests its tendon in the canal of the astragalus, and along the os calcis; another, as stated, is common to it and the last muscle; and a third invests the ten- don along the metatarsal bone, and the first phalanx of the great toe.* The Tibialis Posticus, Is placed between, and concealed by the two last muscles. It arises, by a narrow fleshy beginning, from the front of the tibia, at the under surface of the process which joins it to the fibula, and then gets to the back of the leg through the hole in the up- per part of the interosseous ligament It continues its origin from the whole of the interosseous ligament, and from the sur- faces of the tibia and fibula bordering on this ligament, except- ing 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 malleolus internus, and is confined there by a fibro-cartilaginous noose, and invested by a bursa. It is inserted into the posterior internal part of the os naviculare; and also divides in such a way as to be inserted into * The variations in this muscle consist, principally, in the manner of distri- buting its tendon to that of the small toes, and frequently this connexion is defi- cient. MUSCLES OF THE FOOT. 461 the internal and external cuneiform bones, into the os cuboides, and os calcis. It extends the foot, and presents the sole obliquely inwards. It corresponds with the flexor radialis of the hand. SECT. IV.--OF THE MUSCLES OF THE FOOT. The Extensor Brevis Digitorum Pedis, Is a muscle situated 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 intermixed with the origin of the annular ligament of the ankle. It forms a short, fleshy bel- ly, which is partially divided into four parts; from these parts 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 exten- sor longus, which are spread over their backs. The tendon going to the great toe has its principal insertion into the first phalanx. It extends the toes.* When the Aponeurosis Plantaris is removed frorcTthe sole of the foot, we see three muscles; the middle one, having been co- vered by the large central portion of the aponeurosis, is the Flexor Brevis Digitorum 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 plantaris, and the tendinous septa between it and the con- tiguous muscles. It forms a fleshy belly, going nearly as far forwards as the * Varieties. The internal part, or belly, is sometimes distinct from the adjoin- ing. In some very rare cases all the bellies are insulated, as in birds. Sometimes it sends a tendon to the little toe. 462 MUSCLES. 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 de- ficient. 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 the attachment of the latter to the tendinous slip from the Fexor Longus Pollicis,—to the Massa Carnea Jacobi Sylvii, or Flexor Accessorius,—and to the Lumhricales Muscles. The Flexor Accessorius, Is at the outside of the tendon of the flexor longus. It arises, fleshy, from the inside of the sinuosity of the os calcis, and, by a 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 tendons. Like a second hand to a rope, it assists in flexing the toes. The Lumhricales Pedis, Are four small tapering muscles, which arise from the tendon of the flexor longus, just after its division, or while it is in the act of dividing. One of them is appropriated to each lesser toe, and is inserted into the inside of its first phalanx, and into the tendinous expansion that is sent off from the extensor muscles to cover its dorsum. They increase the flexion of the toes, and draw them inwards. The Abductor Pollicis Pedis, Arises, tendinous and fleshy, from the internal anterior part of the large tuberosity of the os calcis; from a ligament extended from this tuberosity to the sheath of the tendon of the tibialis posticus; from the internal side of the naviculare, and from the cuneiforme internum. MUSCLES OF THE FOOT. 463 It forms the internal margin of the sole of the foot, and is in- serted, tendinous, into the internal sesamoid bone, and into the base of the first phalanx of the great toe. It draws the great toe from the rest. The Flexor Brevis Pollicis Pedis, Is situated immediately at the exterior edge of the abductor pollicis. It consists of two bellies, which are parallel with each other, and 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 pedis. It arises, in common with the calcaneo-cuboid ligament, ten- dinous, from the under part of the os calcis, just behind its con- nexion with the os cuboides, and from the under part of the ex- ternal cuneiform bone. The internal belly is inserted, tendinous, into the internal se- samoid bone, along with the tendon of the abductor pollicis, and the external belly is inserted, tendinous, into the external sesa- moid bone, along with the tendon of the adductor pollicis. Each insertion is continued to the base of the first phalanx of the great toe. It flexes the great toe. The Adductor Pollicis Pedis, Is situated at the outside of the flexor brevis, and is extended obliquely across the metatarsal bones. It arises, tendinous, at the external part of the foot, from the calcaneo-cuboid ligament* 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. 464 MUSCLES. The Abductor Minimi Digiti Pedis, Forms the external margin of the sole of the foot, and is im- mediately beneath the aponeurosis plantaris. It arises, tendi- nous and fleshy, from the outer tuberosity of the os calcis, and also from the exterior part of the base of the metatarsal bone of the little toe. It is inserted, by a rounded tendon, into the 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 within the tendon of the abductor minimi digiti. It arises from the ligament which is extended from the tuberosity of the cuboid bone to the heads of the metatarsal bones; also from the root of the fifth metatarsal bone. It is inserted, by a tendon, into the lower part of the first pha- lanx of the little toe, at its base, and into the head of the meta- tarsal bone of the same toe. It bends the little toe. The Transversalis Pedis, Is placed beneath the tendons of the flexor muscles.* It is small, and lies across the anterior extremities of the metatarsal bones. 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 the flexor brevis pollicis, at the external sesa- moid 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 * The sole is presumed to be upwards. MUSCLES OF THE FOOT. 465 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 double-headed, that is, they arise from the contiguous surfaces of the metatarsal bones. The Interosseus Primus, Digiti Primi Pedis, or the Abductor Indicis Pedis, Is seen superiorly. It is placed between the metatarsal bone of the great toe, and the first small toe, and arises, fleshy, by a double head, from the opposed surfaces of their roots. It is inserted, tendinous, into the inside of the root of the first joint of the first small toe, and pulls it inwards. The Literosseus Secundus, Digiti Primi, or the Adductor Indicis Pedis, Is also external or above. It is situated between the meta- tarsal bones of the first and second small toes, arising 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 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 oppo- site 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. Vol. I.—59 466 MUSCLES. The Interosseus Secundus, Digiti Tertii, or the Adductor Tertii Digiti, Is seen on the upper surface of the foot, occupying the inter- val 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 Interosseous Primus, Digiti Secundi 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 Primus, Digiti Tertii, or the Abductor Tertii Digiti, Is in the sole of the foot. It arises from the inside of the me- tatarsal bone of the third toe, near its root, and is inserted, ten- dinous, into the inside of the base of the first phalanx of the third toe. It draws this toe inwards. The Interosseus seu Adductor, Digiti Minimi, Is on the under surface of the foot. It arises from the inside of the base of the metatarsal bone of the fourth small, or the little toe, and is inserted, tendinous, into the inside of the first phalanx of the little toe. It draws this toe inwards. BOOK IV. OF THE ORGANS OF DIGESTION. The organs of digestion consist in an uninterrupted canal, ex- tending from the lips to the anus; and of numerous glandular bodies placed all along its track, for pouring their secretions into it. This canal, called Alimentary, (Ductus Cibarius,) is in three principal portions: the superior, the middle, and the inferior or terminating. The superior portion is composed of the mouth, the pharynx, and the oesophagus. The middle, of the stomach and small intestine. And the inferior, of the large intestine. The glandular organs are the salivary glands, the pancreas, the liver, the spleen, and an extremely numerous set of mu- ciparous glands, extending from one end to the other of the canal. The organs of digestion may be divided, according to their physical functions, into those of mastication and deglutition, and into those of assimilation. #• BOOK IV. PART I. Organs of Mastication and Deglutition. CHAPTER I. OF THE MOUTH. The Mouth (Cavum Oris) occupies the space in the inferior part of the face, between the upper and the lower jaw. It is separated from the nose by the palatine processes of the supe- rior maxillary and palate bones, and by the soft palate, which is continued backwards from them. It extends from the lips, in front, to the soft palate and pharynx behind, and its floor is formed by the mylo-hyoid muscles. The anterior and lateral periphery of the mouth is constituted by the muscles of the lips and cheeks, covered externally by common skin, and internally by the lining membrane of the mouth. The cavity of the latter is divided into two portions, by the projection of the teeth and of the alveolar processes of the upper and under jaws; these two portions, when the teeth are complete, are separated from each other while the mouth is closed. The anterior portion, which is sometimes called the vestibule of the mouth, varies its size very considerably in mastication, and has its parietes extremely moveable. The ca- paciousness of the posterior admits also of much change, by the motions of the tongue and by the depression of the lower jaw. The whole cavity of the mouth is lined by a membrane, con- tinued over the lips from the skin, and, in many respects, strong- 470 ORGANS OF DIGESTION. ly resembling the texture of the latter; it is, however, much finer; is furnished every where with an epidermis; is very vas- cular, and has beneath it a great number of muciparous glands. Its texture undergoes some changes, according to its position, upon the lips and cheeks, upon the gums and palate, and upon the tongue; all of which will be explained in due season. This lining membrane of the mouth, for the most part thin and very flexible, forms, at several points, folds or duplicatures. Four of them are situated on the middle line of the body, and are called frenula: one goes from the.posterior face of the upper lip to the middle palate suture in front of the central alveolar processes of the upper jaw; a second goes from the posterior face of the lower lip to the front of the symphysis of the lower jaw; a third goes from the under part of the tongue to the pos- terior face of the symphysis of the lower jaw, (fraenulum lin- guae:) and the fourth goes from the front of the epiglottis carti- lage to the middle of the root of the tongue. Besides these, there are some other duplications, which will be mentioned in their proper order. The lips (Labia) are always somewhat thicker at their loose margins than elsewhere; the skin which covers them there, is remarkable for its vascularity, and changes its texture insensi- bly, as it is continued from the face to the lining membrane of the mouth. The upper lip is longer and thicker than the lower, is some- what pointed in the centre, and has on its front surface a verti- cal depression, (philtrum,) beginning at the septum of the nose and going downwards to the centre of the lip. This depression is the remains of a fissure which always exists between the two halves of the lip, in the early foetal or forming stage. The junction of the extremities of the lips constitutes the corners of the mouth (anguli oris.) The lips are composed of muscular fibres, much blended with adipose matter. The muscles which concur to form them are the orbicularis oris and the buccinators; besides which, the up- per lip is furnished on each side with the two levators, with the depressor, and the zygomatici; while the lower lip has its two depressors and a levator. See muscles of the face. OF THE TEETH. 471 CHAPTER II. OF THE TEETH. The Teeth (Dentes) are by far the hardest portions of the human fabric; and though they bear in their composition and appearance a strong analogy with bone, yet they differ from it in their duration, their mode of development, their partial nudi- ty, their nutrition, and in the manner by which they are united to the body. The greater part of the length of each tooth is implanted into the alveolar process of the jaw, and the part so fixed is techni- cally called the root; immediately beyond this a small portion of the tooth is embraced by the gum; this is the neck; and the free, or projecting part of the tooth, is its body. SECTION I. The whole number of.teeth in the adult is thirty-two, sixteen in each jaw, and, when healthy, they are all fixed with so much firmness by the gomphosis articulation, that the very slight de- gree of motion, which, by force, they may be caused to execute, is scarcely perceptible. The differences existing in their shape, have caused anatomists to classify them accordingly; on each side of the middle line of each jaw there are two Incisors, one Cuspated, two Bicuspated, and three Molar teeth. There are also some peculiarities, as they belong to the upper or to the lower jaw; but they correspond exactly with their fellows on the opposite side of the same jaw. The Incisors (Dentes Incisivi) are next to the middle line, and are named from their'being brought to a straight cutting edge, like a chisel, by being bevelled from behind. They are somewhat convex on their anterior faces, but behind they are very concave: owing to their thinness for some distance from the cutting edge, they are apt to be broken. In early life, their 472 ORGANS OF DIGESTION. cutting edge is slightly serrated. They have each but one root, which is conoidal, terminates by a sharp point, and is not un- frequently impressed longitudinally on each side by a superfi- cial furrow. The central incisors of the upper jaw are broader and longer than the outer ones; the anterior face of the latter is more con- vex, and their cutting edge more rounded. The incisors of the lower jaw are much narrower than those of the upper, and have their roots flattened On the sides; they do not differ essentially among themselves, except that the external ones are somewhat wider than the internal. The enamel of the incisors is continued farther down, and is thicker on their anterior and posterior surfaces than laterally; it is also thicker on the front than on the back part.* The Cuspated Teeth (Dentes Cuspidati, Canini,) are next to the incisors, one on each side. Their body is conoidal, and is brought to a sharp point at its summit; the principal obliquity in effecting the latter, being on the side of the interior of the mouth. They are more convex externally, than the incisors, but not so concave internally, they are also thicker and more cylindroid. They have each but one root, which is conoidal, and which, as also the body, is longer than the corresponding portion of any of the other teeth. They stand nearly perpen- dicularly, and are more covered on their sides with enamel than the incisors. The cuspated teeth of the upper jaw have longer roots than those of the lower, and are called, in common language, eye- teeth: those of the lower jaw sometimes are called stomach-teeth. The Bicuspated Teeth (Dentes Bicuspidati,) two in number on each side, are situated behind the cuspate; they are also called small molar. They are almost precisely alike, with the exception that the first is smaller than the other, and resembles rather more the type of the cuspida\us than the second does. Their body is very nearly cylindrical, being flattened, however, on the faces next to adjoining teeth. The masticating surface • Natural History of the Human Teeth, by J. Hunter, London, 1778. OF THE TEETH. 473 of the body is formed into two points, whence the name; one external, and the other internal: the former is the longest and thickest, and, consequently, the most conspicuous. The ena- mel forms an almost circular crown, covering the projecting parts of these teeth. The root of each one is single, but has a deep and well marked fossa on each side running its whole length, and presenting the semblance of an effort at duplicity; it is also conoidal, and sometimes in the upper jaw bifurcated at its end. The bicuspate teeth of the upper and of the lower jaw re- semble each other so strongly that the difference between them is not striking; it is, however, determined by those of the up- per jaw being rather more voluminous and ovoidal in their bo- dies, and having rather longer and larger roots. The Molar Teeth (Dentes Molares,) three in number, on each side, succeed the bicuspated. They are well characterized by their greater size. Their bodies are almost cuboidal, with rounded angles, and are protected with a circular crown of enamel; their grinding surface has five points, three externall}*-, and two internally: the rule, however, is not uniform, as they frequently have only four, and sometimes in the upper jaw only three points. The first molar is the largest of any, and very generally has five points, in the upper jaw it has three roots, two of which are outward, and the other inward; but in. the lower jaw it has • only two roots, one before the other. The second molar of each jaw, with the exception of its being smaller than the first, presents no essential difference from it, either in regard to its body or roots. The fifth point is some- times not so well developed. The third molar resembles the other two in its body, but is smaller than either of them. Most frequently its roots, instead of diverging from each other and standing out distinctly, are imperfectly developed, and fused together. Some slight sepa- ration at their extremities, and the longitudinal depressions on their sides, mark the effort to form three roots for the tooth of the upper jaw, and two for the lower, according to the general rule. Owing to this tooth growing at the posterior extremity Vol. I.—60 474 ORGANS OF DIGESTION. of the alveolar processes, in a place where, from the preceding development of the other teeth, it is much cramped for room, it is not only imperfectly evolved in most cases, but it often takes a very irregular direction; its grinding surface sometimes looking forwards and sometimes backwards. The Alveolar Processes in each jaw form a semi-elliptical row of sockets, for the insertion of the roots of the teeth into them. These processes and the teeth, as Mr. Hunter has very properly explained, have such a mutual dependence upon each other, that the destruction of the one is inevitably followed by that of the other: " If we had no teeth, it is likely we should not only have no sockets, but not even these processes in which the sockets are formed."* The semi-elliptical arrangement ob- served by the teeth is such, that when the mouth is closed, the exterior circumference of the row above projects beyond those below; this is more obviously the case in front; but it also pre- vails at the sides, and depends primarily upon the greater breadth of the incisors of the upper jaw. The grinding surface of the under row, as a whole, is slightly concave from before back- wards, while the opposed surface of the upper row has a cor- responding convexity. Each row, viewed collectively, forms a single edge, in front; but after having passed the cuspidati, it becomes thicker, forms a double edge, and is continued back- wards in that state. SECT. II.--OF THE TEXTURE AND ORGANIZATION OF THE TEETH. The teeth consist in two kinds of substance, one of which is ivory or bone-like, and the other enamel. The Enamel forms the periphery of the body of a tooth, and is distinguished by its whiteness, its brittleness, its semi-trans- parency, and a hardness so considerable that it soon takes down the edge of the best tempered saw or file, so that it is very dif- ficult to penetrate it. It forms a crust upon the body scarcely * Loc. cit. p. 7. TEXTURE AND ORGANIZATION OF THE TEETH. 475 naif a line in thickness, is more abundant upon the grinding surface, and is reduced to a thin edge where it terminates at the neck. When broken, it is seen to be fibrous, and the fibres are so placed as to pass in a direction from the surface towards the centre of the tooth: by which all the friction to which the fibres are exposed is applied against their extremities: an arrangement on the principle of the articular cartilages, and, like them, pre- cisely suited to resist their being rubbed down in mastication, and also to prevent their splitting. Enamel consists principally in a phosphate of lime, with a very small proportion of gelatine. When immersed in a weak acid, its form is retained, but the slightest disturbance afterwards causes it to crumble down into a white pulp. When animals are fed upon madder, the colour of the enamel is not affected;* though it may be changed by dyes applied externally, as ex- hibited by the inhabitants of the Pelew Islands, who, by the use of plants turn it black, and by persons who chew tobacco, in whom it becomes yellow. It is entirely devoid of blood ves- sels. When exposed to heat it becomes very brittle, cracks off from the enclosed bony part of the bqdy, and presents a singed appearance, from the small quantity of gelatine in it. The enamel is not so thick on the deciduous as on the per- manent teeth; it is thicker on the cuspidati than on the incisors, and on the first molar than on the second and third. It is very readily dissolved in strong nitric or muriatic acid. The Osseous portion of the tooth is by much the most abun- dant, as it forms the root, the neck, and the body also, with the exception of the crust of enamel upon it. In its texture it strongly resembles the petrous bone, and is even harder than it, but has no cellular arrangement within. It consists in a se- ries of longitudinal laminae, one within the other, and when de- composed presents about seventy parts of the phosphate of lime and other calcarious combinations, with about twenty of gela- tine and ten of water.t The bony part of a tooth has very nearly the same form with * J. Hunter, loc. cit. I have also verified the same opinion by the same expe- riment. f Pepys. 476 ORGANS OF DIGESTION. the entire body; hence, upon the grinding surface, we have the same modifications of shape as when the enamel is left on. The application of a heated iron to it, turns it to a deep black from the abundance of animal matter in it, which is one way to mark out decidedly the distinction between it and enamel. The ani- mal substance, when separated from the calcarious by muriatic acid, is more compact than the corresponding substance of bone, but, like it, is soft and flexible. The bony part is not vascular; Mr. Hunter, after repeated trials in old and young subjects upon this point, never succeed- ed in making an injection of it; neither could he trace vessels from the pulp to a growing tooth. In growing animals, fed upon madder, he found that the portion which was formed pre- viously to the commencement of this diet, retained its primitive colour, while the part formed during the administration of the diet was affected by it and turned red: again, if the animal were permitted to live some weeks after the madder was suspended, to the preceding condition was superadded a new layer of white. In this experiment, a conclusive difference from common bone is established; for besides, in all cases, the facility of injecting the latter with size, it is susceptible of being dyed throughout by the administration of madder; though the formed parts do not take the latter so readily as the forming. These experi- ments, which are confirmed by my own observations, prove sa- tisfactorily the total absence of blood vessels in the texture of the teeth; and that the colouring matter, when fixed in them, does not depend upon a circulation, but upon its being deposited as the tooth grows, and left there permanently. The teeth are consequently not subjected to a commutation of particles, and to being continually remodelled as the bones are; but.when once formed, they remain in the same state, without change. Every tooth has within its body a cavity, which varies in form and size according to the class to which the tooth belongs: this cavity is continued as a conoidal canal, through the whole length of each root, and terminates, by a small opening, at its point. The cavity is smooth on its internal surface, and is filled with a soft pulpy matter which has no adhesions to the sides of the tooth, but receives, through the opening in the root, TEXTURE AND ORGANIZATION OF THE TEETH. 477 an artery, a vein, and a nerve. The surface of the pulp is moistened by a slight exhalation, and its principal bulk seems to be formed by the nerve, on which the vessels ramify; the latter in youth are much more abundant than in old age.* The base of each projection on the grinding surface of a tooth is hol- lowed out for receiving a process from the pulp. The latter is supposed, by M. Serres, to be a ganglion; it must, however, be a point of much difficulty to fix this character upon it, as the fine cellular substance which holds its constituents together may be readily mistaken for soft nervous fibres. The arteries of the teeth of the upper jaw are derived from the alveolar and the infra-orbitar, and the nerves from the se- cond branch of the fifth pair. The arteries of the teeth of the lower jaw'come from a single branch of the internal maxillary, and the nerves from the third branch of the fifth pair. The in- ferior maxillary, or dental artery, and nerve, go through the canal in the centre of the spongy structure of the lower jaw, and send off branches successively t6 the. roots of the teeth. The residue of the artery and nerve issues through the anterior men- tal foramen. The teeth have been, till lately, very generally ranged among the bones belonging to the skeleton; the continental anatomistsf are, however, now more disposed to view them as the produc- tion of the dermoid tissue, like the nails and the hair; and to withdraw them from the class of bones for the following reasons. The rudiments of the bones are always in a cartilaginous state, and they are gradually changed from that condition to the per- fect bone; the teeth are never so, for the secretion which forms them is from the beginning deposited in the state in which it ever afterwards remains. The bones are all furnished with a periosteum; the teeth are not, but have the surfaces of their bo- dies exposed to the air. The general softening of the skeleton which occurs in some cases of rickets, never is manifested in the teeth.t The texture of the bones is penetrated in every di- * Serres, Essai sur FAnat. et Physiol, des Dents, Paris, 1817. + J. F. Meckel, Hipp. Cloqiiet, Breschet, Serres, &c. ± There is, however, a species of brittleness of the teeth, in which their strength becomes about that of pipe clay. 478 ORGANS OF DIGESTION. rection with blood vessels, but only the central pulp of the teeth is furnished with the latter. - The teeth are composed of two kinds of calcarious matter, one ivory-like, the other enamel; the bones, on the contrary, have but one.* To this we may add, that the teeth have no power of interstitial growth like the bones. It is also said by naturalists, that in mammiferous ani- mals, the teeth present insensible transitions from their most perfect state to a lamellated condition resembling horns and nails.t Some animals, as the shark, have the teeth only ad- hering to the gum and not fixed in sockets, others have them in the stomach: both of which circumstances serve to illustrate still farther the independence of the teeth upon the osseous system; and that their being fixed in sockets belonging to the latter, is merely a collateral and not an essential arrangement SECTION III. The Gums (Gingivae) are a continuation of the lining mem- brane of the mouth over the alveolar processes, but its texture there is much changed; as it becomes more fibrous and vascular, and loses much of its sensibility and capability of being ex- tended. As the gums cover both the lingual and the buccal circumference of the alveolar processes, they adhere very closely to the periosteum, and send in partitions through the interstices between the teeth. They also adhere tightly to the neck of each tooth, so that when the latter is drawn, the gum, unless previously detached, is apt to be lacerated; this adhesion is by a sort of rounded or partially doubled edge, that admits of a slight degree of motion, and which from its thickness, if it be removed by ulceration or by pressure, causes the tooth to ap- pear to project unnaturally from its socket. The teeth, from being united to the jaw by the gum, and by the periosteum being continued over the cavity of the socket; have preserved to them that degree of yielding motion which prevents them, on their unexpected and forcible application to hard bodies, from being fractured, and also saves their sockets.^ • Serres, loc. cit. f Traducteurs de J. F. Meckel. $ J. Hunter, loc. cit. FORMATION OF THE TEETH. 479 SECT. IV.—OF THE FORMATION OF THE TEETH. The teeth, before they become visible, are formed in the in- terior of the maxillary bones. Their rudiments consist in a vascular pulpy substance, having somewhat the shape of the future tooth, and surrounded by two membranes or sacs. The external sac is soft, fibrous, and spongy, and, according to Mr. Hunter, is destitute of vessels. It lines the interior of the socket, thereby forming its periosteum;* adheres closely by its deepest end to the dental nerves and blood vessels, and by its superficial one to the cartilaginous thickening which exists on the margins of the gums of infants. Fox, Blake, and Meckel, consider this sac vascular, which I think more probable, from its being a continuation of the periosteum, or acting as such. Mr. Hunter might, therefore, mean that it was comparatively destitute of vessels, and not totally. It is more spongy, loose, and soft, than the internal sac, and owing to its adhesion to the gum may, by pulling at the latter, be readily drawn out entire with all its contents. The internal sac is extremely vascular, and when successfully injected appears red all over; it is very thin and transparent, and was considered by Bichat as a serous mem- brane. It adheres to the external sac where the latter corre- sponds with the gum; but is elsewhere detached from it with the exception of its base, where it is united by the medium of the vessels that penetrate to the pulp, and in doing so it obtains its extreme vascularity from these vessels. Between it and the pulp there is a mucilaginous fluid like the synovia of the jointsjt which causes the internal sac to protrude like a hernia, if a small puncture be made through the parietes of the external one. The internal sac forms an envelope to the vessels and nerves of the pulp, and being reflected along them, terminates by adhering to the base of the pulp. When the tooth protrudes through the gum, the capsule thus formed by the two sacs is perforated at its apex; and wastes away, like the gum, till the body of the tooth is sufficiently advanced. The two capsules which are then to be considered as the periosteum of the socket * Serres, loc. cit. f Hunter loc. cit. 480 ORGANS OF DIGESTION. and of the root of the tooth, adhere closely to the neck of the latter and to its root. These sacs, or follicles, as they are some- times called, are visible in the tenth week of uterine existence. The Pulp, or'germ of the tooth (Pulpas Dentis) is a very vascular body, and adheres to the, socket only at its bottom, where the vessels enter; it becomes sufficiently distinct about the fourth month of foetal existence, and rises up then from the base of the internal membrane of the sac like a small simple tubercle. In developing itself it acquires the precise form pe- culiar to each tooth, and is actually the mould for it: it is sur- rounded by a very fine vascular web, which is detached from it with much difficulty. The ossification of a tooth first commences on that surface of the pulp next to the gum, by one or more points according to the number of projections, which the future tooth is to have on its grinding surface. The osseous deposite in its very early stage is thin, soft, and elastic, but soon acquires a hard consist- ence. The incisors begin to ossify by three points, the cuspida- tus by one, the bicuspis by two, and the molaris by three, four or five. The several points of ossification continue to increase till their bases come into contact; they then coalesce, and afterwards the tooth grows as an entire body. The triturating surface of the tooth being first formed after this manner, a deposite of bone then takes place along its edges, till the body of the tooth., with the cavity in the centre, is completely built up. In this pro- gress, it gradually surrounds the pulp, till the whole of the lat- ter, excepting its base, is covered with bone. The adhesion of the pulp to the new-formed bone is such as to require some slight force to separate them; but this may be done without rupturing either the one or the other; their surfaces which were in contact are perfectly smooth, neither is there any evidence of a vascular communication between them.* The line of the strongest adhesion is along the latest formed edge of the tooth, and that results from the exact apposition of the pulp and it. * Hunter, Serres, Meckel, loc. cit. FORMATION OF THE TEETH. 481 The crown or body of the tooth being finally finished, its base is somewhat contracted, and thus forms the neck of the tooth. In the subsequent process of the ossification of the roots, the number of the latter is predetermined and always indicated by the number of distinct vessels and nerves which go to the pulp; there are, therefore, three roots to the upper molares, two to the lower, one to the incisors, and so on. When the root is fully formed, its extremity is tapered off to a conoidal point; and the canal or hollow in it containing the pulp is diminished to a proportionate size, so that being also conoidal, its external end appears as a very small opening not large enough to admit a bristle. From the preceding account, it is clear that the bony part of the tooth is formed by an exudation from the external surface of the pulp; consequently, that the external lamina of the crown is the first one deposited, and is originally of the size which it ever afterwards retains; and that the pulp continues this secre- tion of bony matter, from the circumference to the centre; until the tooth, (body, neck, and root,) is completely formed. The pulp, during this process, diminishes continually in size, but elongates itself at the same time towards the bottom of the sock- et; or, in the words of Mr. Hunter, " is lengthened into a fang." As the fang grows in length, the resistance being at its end, causes the tooth to rise through the gum; the socket, in the mean time, has grasped the neck, or beginning fang, and, being modelled upon the root, arises with it* Mr. Hunter's experi- ments on animals, interruptedly fed on madder, prove, conclu- sively, that the bony part of a tooth is formed of lamellae, one placed within another; that the outer lamella being first formed, is consequently, the shortest, and that the internal ones lengthen successively. * The present doctrine about the dermoid origin of the teeth, seems to have pre- sented itself forcibly to the original and sagacious mind of Mr. Hunter; for he says, " Both in the body and in the fang of a growing tooth, the extreme edge of the ossification is so thin, transparent, and flexible, that it would appear to be horny rather than bony, veiy much like the mouth or edge of the shell of a snail when it is growing; and, indeed, it would seem to grow much in the same manner, and the ossified part of a tooth would seem to have much the same connexion with the pulp as a snail has with its shell."—Nat. Hist, of Human Teeth, p. 90. Vol. I.—61 482 ORGANS OF DIGESTION. In the formation of a molar tooth, when the body is finished, ossifications shoot from its brim, and proceed to the centre, where, by their union, they form the commencement of two, three, or even more roots. Mr. Hunter says, that also a dis- tinct ossification is frequently found upon the centre of the base of the pulp; and two or more processes, according to the num- ber of roots to be formed, proceed to join it from the circum- ference of the tooth; and in this way the fangs of the multiform teeth begin. The secretion of enamel begins shortly after the external la- minae of the bony matter commence being deposited. This secretion, which has its mould always previously formed of the bony part, comes from a pulpy substance adhering to the in- ternal face of the internal capsule. The pulpy substance is placed on the part of the capsule nearest to the gum, and faces the pulp which secretes the bone; whatever eminences the one pulp has, the other has the same, but reversed, so that they exactly fit upon each other. This pulp is best seen in the foetus of seven or eight months, and is not very vascular; it is much thinner than the other, and decreases in size as the development of the teeth advances. That which belongs to the incisor teeth is in contact with their concave interior surface, but in the mo- lar it is opposed to their biting surface.* "In the graminivorous animals, such as the horse, cow, &c, whose teeth have the enamel intermixed with the bony part, and whose teeth, when forming, have as many interstices as there are continuations of the enamel, we find processes from the pulp passing down into those interstices as far as the pulp which the tooth is formed from, and there coming into contact with it. " The enamel appears to be secreted from the pulp above described, and perhaps from the capsula which encloses the body of the tooth. That it is from the pulp and capsula, seems evident in the horse, ass, ox, sheep, &c; therefore, we have little reason to doubt of it in the human species. It is a cal- carious earth, probably dissolved in the juices of our body, and thrown out from these parts, which act here as a gland. After * Hunter. FORMATION OF THE TEETH. 483 it is secreted, the earth is attracted by the bony part of the tooth, which is already formed; and upon that surface it crystallizes. " The operation is similar to the formation of the shell of the egg, the stone in the kidneys and bladder, and the gall stone. This accounts for the striated crystallized appearance which the enamel has when broken, and also for the direction of these striae. " The enamel is thicker at the points and bases than at the neck of the teeth, which may be easily accounted for from its manner of formation; for if we suppose it to be always secreting and laid equally over the whole surface, as the tooth grows, the first formed will be the thickest; and the neck of the tooth, which is the last formed part enclosed in this capsula, must have the thinnest coat; and the fang where the periosteum adheres, and leaves no vacant space, will have none of the enamel. " At its first formation it is not very hard, for, by exposing a very young tooth to the air, the enamel cracks and looks rough; but by the time that the teeth cut the gum, the enamel seems to be as hard as ever it is afterwards; so that the air seems to have no effect in hardening it" The preceding passages have been extracted literally from Mr. J. Hunter's Natural History of the Human Teeth, not only on account of their graphical value, but to fix upon him the merit of having first considered the human teeth as a secretion; an opinion the originality of which is falsely attributed to the Baron Cuvier, by M. Serres.* In infants, for several months after birth, the biting margins of the gums upon each jaw are faced by a cartilaginous rising of some lines in elevation, and divided by slight fissures. Its usual appellation is that of Dental Cartilage (Cartilago Den- talis;) it performs the function of teeth, in retaining the nipple, and in mastication, and is analogous to the horny beak of birds, and of some reptiles; it only disappears upon the protrusion of the teeth. In the upper jaw it is about three lines wide, and in the lower about two. If it be removed by thin slices, suc- cessively made, till the margins of the alveoli appear, one * Anat. et Phys. des Dents, p. 63. 484 ORGANS OF DIGESTION. arrives by that means at the ends of the dental follicles or sacs; from which it appears that there is no intermediate sub- stance. In the preceding cartilage are found many small glands, grouped about in different parts of it. They were discovered within a few years past by M. Serres,* of Paris; are about the size of a millet seed, contain a whitish fluid, and when examined by the aid of a microscope do not appear to have any distinct opening or duct, in consequence of which they must be punctured in order to expel their contents. The largest of them are on the internal side of the gum near the molar teeth. According to their discoverer, these glands serve to lubricate the dental cartilages of the infant, but after the protrusion of the teeth they secrete the substance commonly called Tartar, and heretofore falsely attributed to the saliva. Their secretion being of a fatty nature, keeps up the high and brilliant polish which the teeth have till middle age; it being afterwards altered, the teeth then become more dull and yellow. Salivation produces an ex- cessive secretion and deposite of tartar from these glands. J. F. Meckel states, that he has never been able to discover them till towards the period of dentition, from which he is rather in- duced to consider them as a morbid production depending upon irritation, and probably not differing from little abscesses. SECT. V.--DENTITION. Infants have a set of teeth called Deciduous, from their being lost after a certain period of time. Their whole number is twenty, ten in each jaw, consisting on either side of two incisors; one cuspidatus; and two .molares, having a shape corresponding with that of the large grinders in the adult. Several of these teeth fall out about the seventh year, and all of them have dis- appeared about the fourteenth. The time of their first protrusion through the gums is variable, but may, as a general rule, be stated at from the sixth to the eighth month after birth. They appear commonly in pairs. The pairs of the lower jaw have * Loc. cit. DENTITION. 485 precedence in their protrusion; and are immediately followed, successively, by their congeners in the upper. The order of pro- trusion is as follows:— The two central incisors, from the sixth to the eighth month; The two lateral incisors, from the seventh to the tenth month; The first molar tooth, on each side, from the twelfth to the fourteenth month; The cuspated, from the fifteenth to the twentieth month; The second molar, on each side, from the twentieth to the thirtieth month.* The Deciduous teeth, by a process which will be presently explained, drop from the gums and are succeeded by the per- manent teeth. The first permanent molar, about six or seven years of age, by emerging behind the second infant molar, leads the way to the second epoch of dentition, which occurs in the following order:— The central incisors fall out about the sixth or seventh year, and are immediately followed by the central permanent in- cisors; In a few months afterwards, sometimes at the same period, the lateral infant incisors tumble out and are succeeded by the lateral permanent incisors; About the ninth year the first molar teeth fall out, and are succeeded by the first bicuspated; From the ninth to the eleventh year, the second molars fall out, to be succeeded by the second bicuspated; From the eleventh to the twelfth, the infant cuspated are fol- lowed by the adult cuspated; About the end of the twelfth year, the second permanent molars protrude behind the first permanent; And, finally, from the sixteenth to the twenty-fifth year, the third permanent molars or the Dentes Sapientiae, make their ap- pearance. In the jaw of a foetus of three or four months after conception, the beginning of the alveolar processes may be observed, in the condition of a longitudinal groove, deeper and more narrow in front, more shallow and wider behind; and in the bottom of the • Serres, loc. cit. 48G ORGANS OF DIGESTION. groove are small transverse ridges, dividing it into superficial depressions. From this simple condition, ridges begin to shoot out from the opposite sides of the canal near its brim; and form, by their junction, arches across it; more matter being added to these arches, they make, in their progress, a sort of cell for each tooth, open on its alveolar surface. This opening is nearer the internal circumference of the alveolar processes, so that the teeth are almost covered, and probably for the reason advanced by Mr. Hunter, that the gums may be firmly supported before the teeth come through. The rudiments of the teeth which are earliest in their appear- ance may be found in a foetus of two or two and a half months; and at the expiration of three months, it is said that all the germs of both sets of teeth exist in a manner to be distinguished.* The germs of this period are lodged in membranous folds belonging to the gum, to which those of the first dentition are immediately attached, while those of the second are suspended by pedicles of a line or two in length, which circumstance alone permits them to be distinguished. At four months all the germs are con- tiguous to each other, with the exception of the incisors; shortly afterwards they begin to be separated by the rudiments of the alveolar processes; and about the fifth month ossification is perceptible in the infant incisors, and goes on in the other teeth very much in the order of their appearance. The germs of the deciduous teeth are placed in an arc of a circle, the cuspidati being thrown forwards out of the line of the others and somewhat lower; in consequence of which, the first molar border closely upon the incisors. The germs of the per- manent teeth are brought into view by removing the internal face of the jaw, and are at the posterior upper side of the first germs; being, therefore, nearer to the edges of the alveolar pro- cesses. At birth, ossification has taken place in all the infant teeth, though their roots are not yet completed. The rudiments of the permanent teeth, though seen at an early period of foetal ex- istence, do not begin to ossify till after birth. Thus, the first adult incisor and molar begin to ossify about the fifth or sixth * Serres, p. 3. DENTITION. 487 month of life, the second incisor and cuspidatus about the ninth month, the first bicuspis about the fifth year, the second bicuspis and second molar about the sixth or seventh, and the third mo- lar about the twelfth year.* Before the teeth protrude, a pedicle (Gubernaculum Dentis) passes from the alveolar end of the sac of the permanent tooth to the sac of the deciduous tooth; and even when the latter is fully formed and protruded, the same pedicle may be traced to that part of the gum surrounding the neck of the deciduous tooth.t At birth, the rudiments of fifty-two teeth may be found in the two jaws; and, as a general rule at that period, the rudiments of the permanent are more superficial than those of the deciduous; but their position is subsequently changed, so that the first de- scend while the latter ascend.J As the permanent teeth are preparing to protrude, the alveo- lar cavities, in which they are contained, form orifices on the in- ternal surface of the jaw near the edges of the deciduous alveo- lar processes. They are called the Alveolodental Canals, (Itine- ra Dentium.) Those for the incisor and canine teeth, are just behind their corresponding deciduous teeth, and those for the bi- cuspated near and somewhat behind the infant molares. At this period, a bony septum separates almost completely the two or- ders of alveolar cavities from each other, and thereby prevents their mutual interference. The permanent teeth being thus formed in new and distinct sockets, and being kept off from the deciduous, it is clear that the latter cannot be pushed out of their alveoli, as is sometimes supposed, by the growth of the former; and if it did take place, it would produce the great inconvenience of causing them to rise up into the mouth, beyond the level of the other teeth. On the contrary, the deciduous teeth are made loose by the removal of their roots, which progresses till nothing but the neck is left, and then the slightest force applied dislodges them from their position on the gum. This decay of the root is not even affected, accord- ing to Mr. Hunter, by the pressure of the rising tooth, for the * Hunter. f J. Cloquet, Anat. Pi. XXII. fig. 16, 17. Serres, loc. cit. p. 109. \ Serres. 488 ORGANS OF DIGESTION. new alveoli rise with the new teeth, and the old ones decay along with their decaying fangs; and when the first set falls out, the succeeding teeth are enclosed by a complete bony socket. From which it is evident that the change is not produced by mechani- cal pressure, but is a particular process in the animal econo- my.* In farther proof, however, Mr. Hunter has seen two or three jaws where the second deciduous grinders were shedding by the decay of their roots, without there being underneath any tooth to press upon them; and in another jaw he observed the same circumstance in both grinders. In a female patient, in whom the last temporary grinder was loose and was pulled out in consequence, it was not succeeded by another tooth. One of these patients at the time was aged twenty, and the other thirty; from which it would appear, that though the wasting of the fang of a deciduous tooth does not depend upon the pressure of the permanent one, yet the latter determines, in some measure, its expulsion, as without some such influence the period of shedding would not have been so late. From these observations of Mr. Hunter, it would appear, that the pressure of the permanent tooth is not indispensable to the re- moval of the deciduous one in all cases; yet I think it will be most frequently found that much of the decay of the root of the deciduous tooth is owing to its being absorbed by the pressure of the body of the permanent one. The alveoli of the latter, judging from my own observations, are seldom so perfect towards the period of their protrusion as to form a complete separation of the two orders of teeth. In the lower jaw of the adult, there is but one arterial trunk, which supplies the teeth; but in the foetus, and till the age of six or seven years, there are two arteries,-]- and as many canals for containing them. The lowest of these arteries belongs, exclu- sively, to the deciduous teeth: it is distinctly visible in the foetus, augments till the third or fourth year, afterwards it shrinks, and is obliterated about the sixth or seventh year. In some rare cases its canal remains open for a longer time, as M. Serres has met with it in a woman of thirty. Being a branch from the in- ferior maxillary, it enters the bone at a foramen somewhat lower * Hunter, loc. ■j- Serres, loc. cit. p. 17. IRREGULARITIES IN DENTITION. 489 down than the posterior maxillary; and what remains of it after the teeth are supplied comes out at another aperture a little be- low the anterior maxillary foramen, and there anastomoses with the other dental artery. M. Serres supposes that this artery, discovered by himself, and obviously serving in the evolution of the deciduous teeth, by be- ing obliterated before they fall out, destroys their vitality, and, therefore, they become absolutely foreign bodies, the expulsion of which is required by nature on common principles. SECT. VI.--OF IRREGULARITIES IN DENTITION. The process in certain individuals is premature; Louis XIV. was born with two teeth; many instances of the same sort of precosity are recorded by Haller, and other medical writers, in some of which, even ten teeth were found protruded at birth. On other occasions, the process is retarded in a manner equal- ly striking, and varying from the tenth month to the sixth or seventh year. This unusual tardiness is sometimes manifested in particular teeth; thus, 1 know a young gentleman in whom one of the permanent incisors of the upper jaw did not come down before the fourteenth year. Borelli reports a woman in her sixtieth year, who never had teeth; a magistrate of Frede- rickstadt lived to an advanced age, and never had either canine or incisor teeth; he was, however, furnished with molares. The teeth are sometimes supernumerary; it is not very un- common to see this manifested by a single canine or incisor, and more frequently in the upper jaw than in the lower. Occasion- ally, there are several supernumerary teeth. Cases are recorded in which several teeth have been fused or joined together. Bernard Gengha reports, that in a pile of bones belonging to the Hospital S. Esprit, at Rome, he found a cra- nium in which there were only three teeth; in the two upper maxillae one occupied the space of all the incisors and the two cuspidati, and each of the others the space of all the molares of its respective side.* According to the historians, Plutarch and Valerius Maximus; Pyrrhus, king of Epirus, and Prusias, king of * Sabatier, Anat. tome 1, p. 78. Vol. I.—62 490 ORGANS OF DIGESTION. Bithynia, had a single dental piece in each jaw, which stood in the place of the usual allowance of sixteen teeth. These cases are scarcely credible, for the reason, that for them to have oc- curred, the middle palate suture, which is slow in forming, and divides the germs of the two sides from each other, could not have existed during the foetal state, at any time subsequently to the third month; or, what is more compatible with this account, at no time whatever. It is more probable, therefore, that not- withstanding the royal opportunities of cleanliness possessed by these persons, their teeth were neglected, and permitted to in- crust themselves with a dense, thick coat of tartar, which gave them the appearance of a single piece: a circumstance which occurred to Sabatier, in a girl of fifteen or sixteen, and to Four- nier in an individual of the same age and sex.* Another objec- tion is, that as the common law of the germs is to develop them- selves, and to ossify at different epochs, in these two cases they were alj not only proceeding at the same rate, but also joining one another so as to form but a common sac, confounding, there- by, all the known phenomena of dentition. In most persons there are but two sets of teeth; it has hap- pened, however, in several instances, for people about the age of seventy to have one or more new teeth belonging to a third set; they are commonly incisors. J. Hunter saw an example of the kind.f The Countess of Desmond, who lived to her hundred and fortieth year, had, at this period, according to Bacon, a third set of teeth-J Mentzelius narrates a similar case§ in the follow- ing words: " Having accompanied the Elector of Brandenburg on a visit to Cleves, in 1666, there arrived, at the same time, a man aged one hundred and twenty, who exhibited himself for money, and whom I saw at the court of the Elector. His strength of voice manifested that of his breast, and he having run over the gamut, was heard at more than a hundred paces off. Having then opened his mouth, he showed us two rows of pearly teeth, and on the subject of their beauty related ' that being at the Hague two years before, on the same errand which brought him to Cleves, there arrived an Englishman, aged one hundred and * Diet, des Sc. Med. $ Hist. vit. et mort. Col. 536. f Loc. cit. p. 85. § Serres, loc. cit. p. 40. IRREGULARITIES IN DENTITION. 491 twenty; that he visited the latter, and addressed him in the fol- lowing terms: « We are nearly of the same age, for I am only two years younger than you, and I have had the greatest desire to see one older than myself, for I have felt no inconvenience till lately; but during the three days that I have been here, I have had severe headach and dreadful pains in the jaws, which convince me that I am about to die.' ' You are mistaken, my dear friend,' says he to me: 'on the contrary, you are becoming younger, for you are about to teethe again like an infant' < Oh!' answered I, ' I pray to God not to punish me by prolong- ing my days.' 41 left him then and went to bed, and imme- diately after felt the most excruciating pains in the jaws, which were followed by the protrusion of the teeth that you now see.'" The circumstance of a third dentition, has given rise to a ques- tion among physiologists, whether the germs are primarily super- numerary I or whether the gums have within themselves organs capable of forming and of producing new teeth? When such teeth come out in a straggling manner, they hurt the opposite jaw, and require to be extracted. In old persons who have lost all their teeth, there is a carti- laginous hardening of the gum, as in infancy, whereby they still retain some power of mastication. When the body of the tooth has been worn away, nature pre- vents the exposure of its cavity by the deposite of new matter, which may be known by its darker colour, and by its transpa- rency. The muscles of mastication are, the Temporalis, the Masseter, the Pterygoideus Internus, and the Pterygoideus Externus. 492 ORGANS OF DIGESTION. CHAPTER III. OF THE TONGUE. The Tongue (Lingua) is the principal organ of taste, and is also concerned in mastication and in speech. It is an oblong, flattened, symmetrical, muscular body, which extends from the os hyoides posteriorly to the incisor teeth anteriorly, and, being placed at the bottom of the mouth, fills up the space within two sides of the body of the lower jaw. The exact extent of room which it occupies, varies according to its being in a state of re- pose or of activity. The posterior extremity of the tongue is called its base, and arises muscular from the body and the cornua of the os hyoides; it is there considerably thinner than elsewhere, it also has a fibro muscular origin from the centre of the epiglottis cartilage. Some- times a cartilage is found in the middle of the base, and which forms a sort of ball and socket joint with the os hyoides. Its anterior extremity is called the tip or point, is loose, and has a rounded thin termination. Between the point and the base is the body. The superior surface of the tongue is flat, is divided by a middle longitudinal fissure of inconsiderable depth into two equal parts, and is covered by the lining membrane of the mouth, under a particular modification of structure. The inferior sur- face of the tongue, with the exception of its middle part, is also free, and covered by the common mucous membrane of the mouth; but the latter is there very thin, and the veins may be readily seen shining through it. SECT. I.--MUSCLES OF THE TONGUE. The muscles which compose the principal part of the bulk of the tongue, are, the Stylo-glossus, the Hyo-glossus, the Genio- hyo-glossus, and the Lingualis. As these, besides belonging to MUSCLES OF THE TONGUE. 493 the general muscular system, also form so important a part of this organ, with the view of collecting the account of its struc- ture, their description will be repeated. 1. The Stylo-glossus arises from the styloid process of the tem- poral bone, and soon reaches the side of the base of the tongue. Some of its fibres extend to the tip and confound themselves along with those of the superficial lingual muscle, above and be- low the margin of the tongue; while others form a broad trans- verse fasciculus, which is united to the corresponding portion of the other side. 2. The Hyo-glossus arises from the side of the base of the os hyoides, from its cornu, and from its appendix, in a slight degree. It is placed within the stylo-glossus, and extends forwards to the tip of the tongue. Some of its fibres go as far as the middle line of the tongue; others rise almost perpendicularly upwards to its base; while the remainder are confounded, along the mar- gin of the tongue, with the superficial lingual muscle. 3. The Genio-hyo-glossus arises from the tubercle on the pos- terior face of the symphysis of the lower jaw, and immediately after its origin spreads itself after the manner of a fan. Its infe- rior fibres are inserted into the base of the os hyoides, while the remainder, by their diverging, are inserted into the whole length of the tongue from its base to its point. This muscle is in con- tact, side by side, with its fellow, and there is a sort of^ fissure with a small quantity of adipose matter between them. As the fibres of this muscle go from below upwards, they pe- netrate to the upper surface of the tongue; and, consequently, tra- verse the transverse lingual muscles and the superficial lingual. 4. The Lingualis is a small narrow fasciculus of fibres, which arises indistinctly about the root of the tongue, in the yellow cel- lular tissue there, and advances to the tip between the hyo-glos- sus and the genio-hyo-glossus. 5. The Superficial Lingual Muscle (Superficialis Lingua) is n 494 ORGANS OF DIGESTION. broad, thin layer, covering the upper surface of the tongue, be- low the mucous membrane; it begins behind, on a line with the greater papillae, and advances forwards to the tip. Its more in- ternal fibres converge and end at the middle line, but the exter- nal ones terminate above and below, near the margin of the tongue. 6. The Transverse Lingual Muscles (Transversales Lingua, consist in small scattered fasciculi, which are placed below the last, and in the thickness of the tongue, which they traverse at right angles. One end of them, on each side, ceases at the mid- dle line of the tongue, where there is a small seam, and the other end terminates in the membrane of the tongue, at the lateral margin of this organ. These fibres are to be found in the whole length of the tongue, and gradually become more-curved at its base. 7. The Vertical Lingual Muscles (Verticales Lingua) extend from the upper to the under membrane of the tongue. They consist in small scattered fasciculi, like the preceding, and cross them at right angles in traversing the thickness of the fongue.* Many of these fibres appear to me to proceed from the genio- hyo-glossus. SECT. II.--MUCOUS COVERING OF THE TONGUE. The mucous membrane of the mouth, where it forms the frae- num linguae, is over the anterior margin of the genio-hyo-glossi muscles; the same membrane, in going from the base of the tongue to the epiglottis, and forming another fraenum, has, on each side of it, a depression or pouch in which articles of food sometimes lodge. Beneath the last fraenum is a ligamentous tis- sue which runs to the base of the tongue from the front of the epiglottis, and serves to keep the latter erect: some muscular fibres are occasionally seen in this tissue in the human subject: in the black bear of North America, and in some other animals, it consists in a pair of strong muscles. The pouch, on each side, * The preceding views of the minute muscular structure of the tongue have lately been advanced by M. Gerdy, of Paris. See J. Cloquet, Anat. de L'Homme, pi. CXIX. CXX. J. F. Meckel, loc. cit. Note des Traducteurs, vol. iii. p. 313. MUCOUS COVERING OF THE TONGUE. 495 is bordered, externally, by a more superficial doubling of the mu- cous membrane, which passes from the base of the tongue to the side of the epiglottis. The lingual portion of the lining membrane of the mouth, on the upper surface of the tongue, is somewhat cartilaginous, and into it is inserted many of the subjacent muscular fibres. At the base of the tongue this cartilaginous condition is deficient, and its place is supplied by a yellow cellular tissue which adheres to the os hyoides, to the epiglottis, and to many muscular fibres be- low, and has in it mucous follicles. As observed, the mucous membrane, on the under surface of the tongue, offers no peculiarity of organization: but, on the up- per surface, it is remarkable for the unusual size and develop- ment of its papillae, for having its epidermis easily detached, and also for having the muscular structure beneath so closely fixed to it. The anterior two-thirds of the upper surface of the tongue are entirely covered by these papillae. They are so thickly set as to touch one another; and, as they present some peculiarities of form, they are divided into Papilla^ Maximae, or Capitatae, Me- diae, Villosae, and Filiformes. The Papillae Maximae constitute the posterior border of the pa- pillary surface of the tongue, and are about nine in number, though they are frequently fewer, and sometimes more. They are disposed in two oblique rows, which, by converging back- wards, meet and generally form something like the letter V.; the fifth papilla being the angle of the figure. Each of these bodies resembles a cone standing upon its summit, and is- surrounded by a circular fossa which permits it to project but inconsiderably above the general level of the tongue. Sometimes two or more are in the same fossa. The Papillae Mediae, or Fungiformes, are more numerous than the last, and next to them in size; they are enlarged at their loose end into a sort of rounded head, whence their name; they are irregularly scattered over the tongue. Those which are next in size and still more abundant, are the Papillae Villosae. The Papillae Filiformes fill up the intervals of the others, are the smallest, and are found, principally, near the middle of the tongue and at its front extremity. Most commonly the central papilla maxima has the largest 496 ORGANS OF DIGESTION. fossa of any of them, and which is designated by the term fora- men coecum. A little behind this foramen there is frequently another, but not furnished with a papilla, into which some mu- cous follicles discharge their contents: from time to time it has been fallaciously considered as receiving the excretory duct of the thyroid, or of some of the salivary glands. The papillae of the tongue, though they vary in their shape and size, have very much the same structure in regard to the abundance of blood vessels and nerves which enter into their composition. When uninjected, and viewed with the naked eye, their surface appears smooth, but when made turgid by injection, it is covered with little asperities or filaments, which seem to be formed principally of blood vessels, having a very tortuous and superficial course; forming loops, or doublings, in projecting on the surface of the papilla, and anastomosing freely with each other.* Besides vessels, there is a soft whitish substance, sup- posed to be nervous, entering into the composition of each fila- ment The larger papillae on the back part of the tongue are supplied by the glosso-pharyngeal nerve, and the papillae on its front part by the trigeminus or fifth pair. The surface of the tongue between the papillae maximae and the os hyoides is destitute of papillae, and is covered only by the common mucous membrane of the mouth, having beneath it many muciparous glands, which in different individuals produce promi- nences more or less elevated. The Epidermis, which is found upon all other parts of the lining membrane of the mouth, is also continued over the whole upper surface of the tongue, and consequently invests each papilla; it is called there Periglottis. It is soft and humid, may be detached, by maceration, and is frequently detached in fevers. On its up- per surface, it, when detached, will have many elevations; while on the lower there will be corresponding excavations, which to superficial observation give it the appearance of being cribri- form. The tongue is supplied with arteries, principally from the lin- gual branch of the carotid, and with nerves from the hypo-glossal, * Soemmering, Anat. J. Cloquet, Anat. pi. cxix. THE PALATE. 497 the fifth pair, and the glosso-pharyngeal. The former is supposed to be exclusively appropriated to its muscular movements, and the two latter to its sensations. Its faculty of taste seems to be most active at the tip; on the sides, and near the middle, behind, it is inconsiderable. The soft palate seems also to participate in the function of taste. CHAPTER IV. OF THE PALATE. The Palate (Palatum) is composed at its anterior part of the palatine processes of the superior maxillary and palatine bones, covered above by the pituitary membrane, and below by the lining membrane of the mouth. This portion of it is the hard palate, and separates the mouth from the nose. Behind it is a membranous portion called the soft palate, which separates par- tially the mouth from the upper part of the pharynx. That part of the lining membrane of the mouth which covers the hard palate, has a hard cartilaginous feel, and is not so vas- cular or sensible as other parts. It has a ridge in its centre just beneath the middle palate suture, and from each side of it there are transverse ridges extending to the alveolar processes. This arrangement is more evident at its anterior part, and in middle- aged persons; in the old it is faint, and frequently does not exist when the alveoli are gone. Beneath this membrane, particular- ly at its posterior part, the muciparous glands are very abundant and closely set against each other. The. Soft Palate (Velum Pendulum Palati) has an oblong shape, and being continued from the posterior margin of the hard pa- late it is stretched across the back of the mouth from one side to the other, and obliquely downwards and backwards. Its inferior margin, which is free, offers in its centre a projection of half an Vol. I.—63 498 ORGANS OF DIGESTION. inch or three quarters in length, which is the Uvula. From each side of the latter there proceed two crescentic doublings of the lining membrane of the mouth, called the lateral half arches of the palate. The Anterior Half Arch is more distinct than the other, and arising at the side of the uvula by one end, terminates by the other in the side of the root of the tongue. The Posterior Half Arch arises from the side of the uvula near the last, and diverging from it backwards, and outwards, has the other end lost gradually in the lining membrane of the pharynx near its middle. In the depression between these duplications, on either side, is the Tonsil Gland. The space bounded in front and behind by these lateral half arches is the Fauces, and the anterior opening into it, is the Isthmus of the Fauces. When the mucous membrane of the soft palate is removed, its muscles are exposed, and are as follow:— 1. The Constrictor Isthmi Faucium is a small fasciculus of fibres, on each side, within the duplicature of the anterior lateral half arch. ' It 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 papillae maximae. It tends to close the opening between the mouth and the pha- rynx. 2. The Palato-Pharyngeus is also a small fasciculus, within the duplicature forming the posterior lateral half arch. It arises from the middle of the soft palate near the root of the uvula, and is inserted into the pharynx at the space between the middle and lower constrictors, behind the stylo-pharyngeus, and into the su- perior posterior margin of the thyroid cartilage. It spreads it- self put considerably, so as to cover, along with the stylo-pha- ryngeus, almost the whole lateral portion of the pharynx to its lower part. It draws the soft palate downwards. 3. The Circumflexus, or Tensor Palati, is behind the pterygoid process of the sphenoid bone. It arises from the spinous process of the latter behind the foramen ovale, and from the contiguous part GLANDS OF THE MOUTH. 499 of the Eustachian tube; it then passes downwards in contact with the pterygoideus internus muscle, and terminates in a broad ten- don below, which winds around the hook of the internal ptery- goid process, and is inserted into the soft palate near its middle, and into the posterior lunated edge of the palate bone. It spreads out or extends the palate. 4. The Levator Palati is on the inner side of the last. It arises from the point of the petrous bone, and from the contigu- ous part of the Eustachian tube, and passes downwards to be inserted into the soft palate. This muscle, in the dissection of the pharynx may be seen between its external edge, and the pte- rygoideus internus muscle. It draws the soft palate upwards. 5. The Azygos Uvulae is in the centre of the soft palate and of the uvula. It arises from the posterior pointed termination of the middle palate suture, and goes down into the uvula. It draws the uvula upwards, and diminishes the vertical breadth of the soft palate. When the mucous membrane is removed, the upper constrictor of the pharynx appears between the anterior and the posterior half arches. CHAPTER V. OF THE GLANDS OF THE MOUTH. These glands consist in such as are muciparous, and in such as are salivary. SECT. I.--MUCIPAROUS GLANDS. These glands (Glandula Mucipara) are whitish, somewhat oval and flattened, and are from the fraction of a line to two lines in diameter: they are found in great abundance beneath the 500 ORGANS OF DIGESTION. lining membrane of the mouth at several places, to wit: on the lips, (Gland. Labiates;) on the cheeks, (Gland. Buccales;) and also, as mentioned, at the posterior part of the upper surface of the tongue, (Gland. Mucip. Lingua.) The layer of them, (Gland. Palatini,) which is found at the posterior part of the hard palate, is also continued over the anterior and the posterior surface of the soft palate, especially the latter surface. The Tonsils, (Tonsilla, Amygdala,) situated, as observed, one on each side, between the half arches of the palate, are six or eight lines long, four or five wide, and about three thick. They are rather a collection of large mucous follicles, than a congeries of glandular bodies, in consequence of which their surface is very- much reticuled. Owing to their being placed upon the upper constrictor of the pharynx, their mobility is very striking and considerable. A great many small pores are observed on the internal surface of the mouth, which are the orifices of the ducts of the mucipa- rous glands. SECT. II.—SALIVARY GLANDS. On either side of the neck, bordering upon the mouth, there are three glandular bodies for the secretion of saliva; they are the parotid, the submaxillary, and the sublingual. The fluid secreted from them is of great service in digestion, and is blended with the food in mastication, and in swallowing. According to Berzelius, it has a considerable affinity to oxygen; and consists in a white mucous substance, having, in a state of solution, the saline articles usually found in the serum of the blood. The Parotid Gland (Glandula Parotis,) is the largest of the three, and, like the others, is of a light pink colour. Owing to the space into which it is crowded, it is of a very irregular figure. It fills up the cavity on the side of the head between the mastoid process and the ramus of the lower jaw, extending beyond the edge of the latter so as to cover the posterior margin of the mas- seter muscle. It is somewhat pointed at its fore part. Its ver- tical length reaches from the zygoma above, to the angle of the jaw below; sometimes, indeed, a little lower down. In thick- SALIVARY GLANDS. 501 ness it extends from the integuments externally, to the styloid process, the styloid muscles, and the tendon of the digastricus, internally, being there only separated from the internal carotid artery by these parts. It is traversed from behind forwards by the portio-dura nerve, and from below upward^ by the external carotid artery and the temporal vein. This gland has no appropriate capsule, but being covered, on its external face, by the continuation of the fascia superficialis of the neck, prolongations are sent from the fascia which penetrate it in every direction, and keep its lobules together. Its duct (Ductus Stenonia?ius) departs from its anterior edge a few lines below the zygoma, and traverses the outer face of the masseter muscle, in a line, according to the observations of Dr. Physick, drawn from the lobe of the ear to the end of the nose. It is about the size of a crow quill, is hard and tendinous, with thick parietes. It lies close to the masseter muscle, and at the anterior edge of the latter penetrates a pad of fat commonly found there on the side of the cheek; it then perforates the pos- terior end of the buccinator, so as to have its oral orifice oppo- site the second large molar tooth of the upper jaw. On opening the mouth wide during a state of fasting, a jet of saliva will sometimes indicate the position of this orifice. A small gland (Gland. Accessoria Parotidis) is sometimes found between this duct and the zygoma; it varies in form and size, and has a distinct excretory canal discharging itself into the pa- rotid duct. The Submaxillary gland (Glandula Submaxillaris) is not more than a third or one half the size of the last, and has a more re- gular form in being somewhat ovoidal. It is accommodated in the depression on the side of the neck formed by the body of the lower jaw externally, by the mylo-hyoideus muscle above, and by the tendon of the digastric below. The platysma myodes inter- venes between it and the skin. It almost touches the parotid gland behind, being separated from it only by a process sent in from the fascia superficialis, and continuous with the ligament going from the styloid process to the ramus of the lower jaw. As it extends to the posterior margin of the mylo hyoideus mus- oyj* ORGANS OF DIGESTION. cle, it there touches the sublingual gland. The facial artery either passes through it or is very much connected with it. Its colour and appearance are the same with the parotid; but its lobules are more easily separated, as they are held together only by weak cellular substance, which forms a sort of capsule to them. Its duct, (Ductus Wharlonianus,) which is single, comes from the assembling and junction of branches from the several lobes. It is much thinner, more extensible, and larger in pro- portion than the parotid duct; and being directed backwards, winds over the posterior edge of the mylo-hyoid muscle, in order to get to the cavity of the mouth. It then passes along the internal face of the sublingual gland, below the tongue, and terminates by a small projecting orifice on the anterior margin of the frae- num linguae. A continuation of the substance of this gland, of a few lines in thickness, described by Bartholin, is found at the posterior end of the sublingual gland, and has its excretory duct sometimes opening at the side of the duct of Wharton, and, on other occa- sions, into one of the ducts which issue from the sublingual gland. When this common duct exists, it is called the canal of Bartho- lin, (Ductus Bartholinianus,) who first discovered it in the lion, in 1684. The Sublingual Gland (Glandula Sublingualis) is an oblong body, covered by the lining membrane of the mouth, but visible when the tongue is turned up. It is placed above the mylo- hyoid muscle, along the under surface of the tongue, and is rea- dily distinguished by its ridged unequal surface, projecting into the mouth. It is not so large as the submaxillary gland. Its lobules are smaller than those of the preceding gland, and are also whiter and harder. Instead of having but one excreto- ry duct, it has several; sometimes fifteen or twenty of them are discernible: on other occasions, several of them are collected into one or two principal trunks, (Ductus Riviniani,) and open either directly into the mouth, or into the duct of Wharton. These several openings are found along the bottom of the mouth, on either side below the tongue. Several small salivary granu- lations or glands border on the sublingual. THE PHARVNX. 503 The position of the salivary glands is such, that they are much moved and pressed upon by the neighbouring parts in mastica- tion, independently of the emission of their fluid being provoked by hunger. Owing to the similitude of their structure, and to their not being regularly supplied like other glands with capsules, their limits are occasionally so inexactly traced, that they con- tinue into each other by adjacent points, and form thus an unin- terrupted chain.* They all are of the conglomerate kind, or, in other words, con- sist in a congeries of smaller glands or lobes and lobules. They are well furnished with arteries; which are branches, from the external carotid, and go in several trunks instead of in a leading one. The parotid is commonly supplied by trunks coming di- rectly from the external carotid, the submaxillary is supplied from the facial artery, and the sublingual gland from the lingual artery. Their nerves come from the fifth pair, and from the portio dura. The retrograde injection of their excretory ducts shows how the latter are formed by the assembling of branches from the different lobules. These ducts consist of two coats, a fibrous one externally, and a mucous one internally. CHAPTER VI. OF THE PHARYNX AND CESOPHAGUS. SECT. I.--OF THE PHARVNX. The Pharynx (Pharynx) is a large membranous cavity, placed between the cervical vertebrae and the posterior part of the nose and mouth. It extends from the base of the cranium to the lower part of the cricoid cartilage, or to the lower part of the fifth cervical vertebra. It is in contact, behind, with the verte- • Bichat, Anat. Descrip. vol. v. p. 24. 504 ORGANS OF DIGESTION. brae and the muscles lying upon them, being simply attached there by loose cellular substance; above, it adheres to the cunei- form process of the os otcipitis, and to the point of the petrous portion of the temporal bones; in front, to the posterior margin of the upper and of the lower maxilla, to the cornua of the os hyoides, the side of the thyroid and of the cricoid cartilage; and below it is continued into the oesophagus. In consequence of these several attachments the pharynx is kept open, or, in other words, its sides are prevented from collapsing, and it is drawn up and down in the motions of the tongue and of the larynx. The Pharynx consists in three coats: an external one, formed by three muscles, on each side, one above the other, and called constrictors; an intermediate cellular coat; and an internal mu- cous one. 1. The Musculus Constrictor Pharyngis Inferior, arises from the side of the cricoid, and from the whole length of the side of the thyroid cartilage. From these points its fibres diverge to the middle vertical line on the back of the pharynx, where they join with their congeners of the opposite side. The lower fibres are nearly, if not completely, horizontal, and those above in- crease successively in their obliquity upwards, so that the upper ones are extremely oblique, and reach, at their termination, to within twelve or fourteen lines of the upper part of the pharynx. 2. The Constrictor Pharyngis Medius, arises from the cornu and appendix of the os hyoides, and from the ligament connect- ing the posterior end of the latter with the upper cornu of the thyroid cartilage. Its inferior margin is overlapped by the su- perior margin of the last; its fibres there are also horizontal, and, indeed, somewhat convex downwards; while the superior fibres become successively more oblique in ascending. It is in- serted by the middle line behind, into its fellow of the opposite side, and by its point above into the cuneiform process of the os occipitis, just in advance of the recti majores muscles. 3. The Constrictor Pharyngis Superior, arises from the ptery- goid processes of the sphenoid bone, at their lower end; and be- low them from the back part of the upper and under jaws be- THE PHARYNX. 505 hind the last molar teeth, it is also connected at its anterior mar- gin with the buccinator muscle, and with the root of the tongue. It has its lower edge overlapped by the constrictor medius; and its fibres are more horizontal, generally, than those of the pre- ( ceding muscles. It is inserted into its fellow by a middle line, the upper end of which adheres to the cuneiform process of the os occipitis. The superior margin of this muscle between the pterygoid process of the sphenoid, and the cuneiform process makes a crescentic line, the concavity of which is upwards. The constrictor muscles of the pharynx, by their successive contraction, convey the food from the mouth into the oesophagus. The .Stylo-Pharyngeus, which is mentioned among the muscles of the neck, forms an interesting portion of the structure of the pharynx, and may be considered on a footing with the longitu- dinal fibres of the oesophagus and of the intestines; being in- tended to shorten the pharynx by arising from, or having a fixed point at the styloid process above, and by being joined into the pharynx below. Its fibres being first of all on the outside of the upper constrictor, are readily traced between the lining mem- brane and the two lower constrictors to the posterior margin of the thyroid cartilage; into which, after spreading out considera- bly, they are finally inserted. The intermediate membrane of the pharynx is merely con- densed cellular tissue, which joins the muscular to the mucous coat. The internal or mucous membrane of the pharynx, which lines the last, is spread uniformly over it; the only irregularity of its surface being made by the presence of mucous follicles and glands, which are more abundant above "between the pos- terior margins of the two stylo-pharyngei than below. It is co- vered by a very delicate epidermis, and is supplied with two ar- teries on jeach side, the superior and inferior pharyngeal, the first qf which comes from the internal maxillary, and the second from the external carotid. It exhibits a number of small veins, which run into the internal jugular or some of its branches. Vol. I.—64 506 ORGANS OF DIGESTION. The shape of the cavity of the pharynx is oblong and cylin- drical, being somewhat larger at its superior end; at the latter place, where it is attached to the petrous bone, it-presents a deep corner, which gives it a square appearance there, and has a collection of muciparous follicles somewhat like the tonsil gland. Anteriorly, and above, it is continuous with the Eusta- chian tubes, and with the posterior nares; just fielow this, with the fauces and mouth, and below the root of the tongue with the cavity of the glottis or larynx. At its lower extremity, where it terminates in the oesophagus, it is so contracted as to suit the size of the latter cavity. SECT. II.—OF THE ffiSOPHAGUS. The oesophagus is the tube just in front of the spine and be- hind the trachea, which conducts food from the pharynx into the stomach. When inflated it is of a cylindrical shape, about ten or twelve lines in diameter: it is nine or ten inches long, and gradually increases in its size from above downwards: in its state of repose it is flattened from before backwards. Its de- scent is not entirely vertical, but.at the lower part of the neck it inclines somewhat to the left of the middle line, and is, there- fore, rather to the left side of the trachea than behind it. It passes down the thorax in the posterior mediastinum, being bounded on its left side by the aorta, and on the right by the vena azygos. It keeps during the early part of its course in this cavity, in front of the middle line of the spine; but lower down it inclines again slightly to the left side, in front of the aorta, in order to reach the oesophageal orifice of the diaphragm, through which it penetrates into the abdomen. In all this pas- sage the oesophagus is united to adjacent parts by a loose cellu- lar tissue. The oesophagus is composed of three coats: the muscular; the cellular or nervous; and the mucous. The muscular coat is the external, and very strong. It con- sists in two well marked laminae of muscular fibres. The most exterior is the thickest, and goes, longitudinally, from one end to the other of the tube; commencing, according to J. F. Mec- ESOPHAGUS. 507 kel, by three fasciculi above; one of which arises, tendinously, from the posterior face of the cricoid cartilage, and the other two, one on each side, from the inferior constrictor of the pharynx. These fasciculi descend for an inch or two before they spread out into a uniform membrane. The internal mus- cular lamina consists in circular fibres, which may be considered as a continuation of the lower margin of the inferior constrictor of the pharynx, and are either horizontal or slightly spiral; they are rather deficient on the fore part of the oesophagus for an inch at its superior extremity. Individually,their length is inferior to the circumference of the oesophagus. The cellular coat is next in order, and serves to unite the muscular and the mucous together. It adheres much more closely to the latter than it does to the former, has no adipose matter in it, but is found to be abundantly furnished, more par- ticularly towards its upper end, with small muciparous glands; it also serves to transmit the blood vessels through the struc- ture of the oesophagus. The mucous coat of the oesophagus is the most internal; in the undistended state it always presents many longitudinal folds, going from one end to the other, but sometimes blending with each other, owing to the contraction of the circular muscular fibres. When suspended in water its fine velvety appearance is very perceptible, as well as the mucous lacunae or glands which open Upon its internal surface. As it is a continuation of the mucous membrane of the pharynx, it has the same gene- ral appearance, but is rather whiter. Its internal surface is also covered by a delicate epidermis, which ceases at the cardiac orifice of the stomach, and may be raised in shreds by macera- tion and byjioiling; in some pathological conditions it becomes very distinct by acquiring more thickness and solidity, than what belong to its healthy state. The arteries of the oesophagus are derived from the inferior thyroidal, from the thoracic aorta, and from the gastric. Its nerves come principally from the pneumogastric. INDEX TO VOL. 1. Abductor Pollicis Pedis, Adductor Pollicis Pedis, Abductor Min. Digit. Pedis, Alimentary Canal, Alveolar Processes, Adductor Metacarpi Min. Digiti, Aponeurosis Plantaris, . . Adductores Femoris, Annuli Junct. Ligamentosi, . Abductor Pollicis Manus, Adductor Pollicis Manus, Abductor Indicis, Abductor Min. Digit., Aponeurosis Palmaris, . Anconeus, Abdomen, Muscles of, . Abdominal Fascia, Ankle Joint, . Articulations, Articular Cartilages, Americans, Astragalus, . Articulation of Wrist, Articulation, Sterno-Clavicular, Auricularis, Arm, Muscles of, Ankle, Ligament of, Bones, Texture of,. Composition of, . Vascularity of, Growth of, Individual, Carpal, Buccinator, 510 INDEX. Biceps Flexor Cubiti, . Brachialis Internus, Bursa of Fingers, Biceps Flexor Cruris, Bordeu, Bicorn Ligament, Callus, Cartilages of Ribs, Carpus, Caucasian Race, • Clavicle, Cervical Vertebrae, Coccyx, Cranium, Cranium, Internal Face of, Cartilages, Cartilages, Accidental, Coccygeal Ligament, Calcis, Cuboides, Cuneiform Bones, Cotyloid Ligament, Crucial Ligaments, Calcaneo-Scaphoid Ligament, Costo-Clavicular Ligament, Conoid Ligament, . Coracoid Ligament, Carpal Articulation, Calcaneo-Cuboid Ligament, Cellular Substance, Cellular Atmosphere, . Cutis Vera, Cutis Anserina, Cuticula, Cyanosis, Compressor Naris, Corrugator Supercilii, . Cremaster, Cervicalis Descendens, Complexus, Coraco-Brachialis, Cruraeus, Development of Skeleton, Diaphysis, Dorsal Vertebrae, Diploe, Dermoid Covering, INDEX. 511 Dutrochet, Depressor Labii Sup., . Depressor Anguli Oris, Depressor Labii. Inferioris, Digastricus, Diaphragm, . Deltoides, Digestion, Organs of, . Dental Cartilage, Dental Glands, Dentition, Dentition, Irregularities of, Epiphyses, Ethmoides, . Elbow Joint, External Cellular Tissue, Elain, . Epidermis, . Extensor Carp. Rad. Long., Carp. Rad. Brev., Carpi Ulnaris, Digit. Com., Metacarpi Pollicis, . Pollicis Minor, et Major, Long. Digit. Pedis, . Prop. Poll. Pedis, Brev. Digit. Pedis, . Enamel, Face, . Facial Angle, Fingers, Fontanels, Frontal Bone, Foot, Motions of, Fibro-Cartilage, . Fore Arm, Mgtions of, Fibula, . Foot, Bones of, Finger Joints, Foot, Articulations of, . Fore Arm, Articulations of, Fat, . Fascia Superficialis Colli, Fasciae Superficialis Abdominis, Fascia Profunda Colli, Fascia Transversalis, . Fascia Iliaca, 136, 168 171 198 177 122 244 256 206 219 222 298 310 291 325 512 INDEX. Fasciae of Upper Extrem., Fasciae of Lower Extrem., Flexor Carpi Ulnaris, . Flexor Digitorum Subl., Flexor Digit. Profund., Flexor Pollicis Longus, Fore Arm, Muscles of, Flexor Brev. Poll. Manus, Flexor Parv. Min. Digit., Flexor Carpi Radialis, Fascia Lata, Fascia Cruralis, Fasciae of Foot, Flexor Long. Digit. Pedis, Flexor Long. Poll. Pedis, Foot, Muscles of, . Flexor Brev. Digit. Pedis, Flexor Accessorius, Flexor Brev. Poll. Pedis, Flexor Min. Digit. Pedis, Frenulae of Mouth, Femoral Bone, Gagliardi on Bones, Glenoid Ligament, Gaultier, Genio-Hyoideus, . Gracilis, Glutaeus Magnus, . Glutaeus Medius, Glutaeus Minimus, Gemini, Gastrocnemius, Gums, Humeral Bone, Hyoides, Hand, Bones of, Head, Head, Development of Foetal, Head, External Surface of, Hand, Motions of, Hip Joint, Hunter, . Hairs, Hand, Muscles of, Hey's Ligament, Half Arches, of Palate, INDEX. 513 Ilium, . Innominata, . Ischium, Intervertebral Substance, Ilio Lumbar Ligament, Inferior Extremities, . Inf. Extremities in Standing, Inf. Extremities in Locomotion, Inf. Palmar Ligaments, Interosseous Ligament of Leg, Inter-Clavicular Ligament, . Interosseal Lig. of Fore Arm, Integuments, Internal Cellular Tissue, Intercostal Muscles, Iliacus Internus, Inter-Spinales, Inter-Transversarii, Infra-Spinatus, Indicator, Interosseous Muscles of Hand, Interosseous Muscles of Foot, Itinera Dentium, . Joints, Page 95 95 98 265 275 212 234 240, 245 297. 308 283 290 317 322 S84 400 410 411 416 430 434 464 487 260 i Knee Joint, Lumbar Vertebrae, Ligamentous Tissue, Lower Jaw, Articulations of, Ligaments, Yellow, Leg, Motions of, Lower Extremities, Joints of Lateral Lig. of Knee, . , Ligament. Alare, . Ligament. Mucosum, Lacerti, Muscles of, Levator Labii Sup., Levator Anguli Oris, Levator Labii Inferioris, Longus Colli, Latissimus Dorsi, Levator Scapulae, . Levatores Costarum, Lig. Carpi Volare, Lig. Carpi Dorsale, Ligamenta Vaginalia, Lumhricales, . Vol. I.—65 302 83 257 263 269 243 299 304 307 307 352 368 368 370 380 402 404 411 414 413 425 431 514 INDEX. Leg, Muscles of, . Lumhricales Pedis, Little Toe, Muscles of, Lips, Longissimus Dorsi, Malae, Maxillare Inferius, Maxillare Superius, Metacarpus, Medulla, Mongolian Race, . Moderator Ligament, . Middle Straight Ligament, . Metatarsus, . Metacarpal Joints, Metatarsal Joints, Muscles, General Anatomy of, Membrana Musculorum, Muscular Fibre, . Muscular Motion, Masseter, Muscles of the Back, . Mylo-Hyoideus, . Multifidus Spinae, Mouth, . Mouth, Glands of, Muciparous Glands, Page 453 462 464 470 405 143 145 137 196 64 114 272 272 228 295 315 351 352 353 357 371 401 379 409 469 499 499 Nasal Bones, Negroes, Nose, Nails, 141 173 164 343 ffisophagus, . Ossa Longa, Lata, Crassa, . Occiput, Ossification Osteogeny, Orbits, . Occipito-Vertebral Articulation, Obturator Ligament, Occipito-Frontalis, Orbicularis Palpebrarum, Orbicularis Oris, . Omo-Hyoideus, Obliquus Ext Abdominis, Obliquus Int. Abdominis, Obliquus Capitis, 506 51 126 69 66 166 270 277 365 367 371 378 386 388 410 INDEX. 515 Opponens Pollicis, Obturator Internus, Obturator Externus, Osseous Part of Teeth, Orbicular Ligament, Page 432 450 451 475 290 Parietal Bones, Palate Bones, Pelvis, Development of, Mechanism of, . Male and Female, Periosteum Externum, . Periosteum Internum, Phalanges of Hand, Pubes, . Pelvic Vertebrae, Perichondrium, . Pelvis, Ligaments of, . Patella, Phalangial Articulations, Patella, Ligaments of, Posterior Ligaments of Knee Peroneo-Tibial Articulations Pubic Ligament, Papillae Tactus, . Plica Polonica, Pterygoideus Externus, Pterygoideus Internus, Platysma Myodes Muscle, Pectoralis Major, Pectoralis Minor, . Pyramidalis, Psoas Parvus, Psoas Magnus, Pronator Radii Teres, Palmaris Longus, Pronator Quadratus, Palmaris Brevis, Pectineal Fascia, . Pectinalis, . Pyriformis, Peroneus Tertius, Peroneus Longus, Peroneus Brevis, Plantaris, Popliteus, Pulp of Tooth, •.- Papillae of Tongue, 516 INDEX. Periglotfis, Palate, Soft, Palate, Muscles of, Parotid Gland, Pharynx, Pharynx, Muscles of, Page 496 497 498 500 503 505 Quadratus Lumborum, Quadratus Femoris, Radius, Ribs, Radio-Ulnar Articulation, Radio-Carpal Articulation, Round Ligament, . Ribs, Articulation of, . Rete Mucosum, Rectus Capitis, Rectus Abdominis, Rhomboideus Major, Rhomboideus Minor, Rectus Capitis Posticus, Kectus Femoris, . 398 451 192 ]06 291 292 300 278 333 380 390 404 403 409 443 Spongiosum Inferius, Sacrum. Scapula, Scarpa on Bones, . Sella Turcica, Shoulder Skeleton, Anatomy of, Spine, . . Spine, Uses of, Sphenoides, Sternum, Sutures, Sutures, Uses of, Sutures, Formation of, Synovial Capsules, Stylo-Maxillary Ligament, Spine, Ligaments of, Sacro-Spinous Ligament Shoulder, Motions of, Scaphoides, Sesamoid Bones, Semi-Lunar Cartilages, Sacro-Iliac Ligament, Sciatic Ligament, . Symphysis Pubis, \ 144 84 182 59 158 180 49 76 88 131 109 148 151 152 260 264 265 275 204 225 200, 232 305 275 276 277 INDEX. 517 Semilunaire, Shoulder, Articulations of, Scapulo-Humeral Joint, Sacciform Ligament, Serosity, Stearin, Skin, Sebaceous Organs, Shape of Muscles, Stei no-Cleido Mastoideus, Sterno Hyoideus, Sterno-Thyroideus, Stylo-Hyoideus, Stylo-Glossus, Stylo-Pharyngeus, Scalenus Anticus, Scalenus Medius, Scalenus Posticus, Subclavius, . Serratus Magnus, Serratus Inferior Posticus, Serratus Superior Posticus, Splenius, Sacro-Lumbalis, . Spinalis Dorsi, Semi-spinalis Cervicis, Semi-spinalis Dorsi, . Supra Spinatus, . Subscapularis, Supinator Rad. Long., Supinator Rad. Brev., Shoulder, Muscles of, Sartorius, Semi-tendinosus, . Semi-metnbranosus, Soleus, Salivary Glands, Stenos Duct, Submaxillary Gland, . Sublingual Gland, Temporis, . Triqiietra, Thorax, Development of, Mechanism of, . Articulations of, 128 153 105 113 115 278 518 INDEX. Trapezium, . Transverse Ligament, Tibia, Tarsus, Toes, Bones of, . Joints of, . Thigh, Motions of, Muscles of, Thumb, Articulations of, Trapezoid Lig., . Triangular Lig., Tarso-Metatarsal Articulation, Tendons, Thyreo-Hyoideus Muscle, Temporalis, Trunk, Muscles of, Triangularis Sterni, Transversalis Abdominis, Transversalis Cervicis, Transversalis Pedis, Trapezius, Trachelo Mastoideus, . Teres Minor, Teres Major, Triceps Extensor Cubiti, Triceps Surae, Tensor Vaginae, . Tibialis Anticus, Tibialis Posticus . Teeth, Formation of, Tongue, Muscles of, Mucous Covering of, Page 193 271 216 222 231 315 240 443 296 285 285 313 362 377 372 76 401 385 389 407 464 401 407 416 417 419 457 443 453 460 471 479 492 492 494 Ulna, . Unguis, Upper Extremities, Development of, Mechanism of, Articulations of, Muscles of, 188 142 180 200 201 283 412 Vertebrae, Development of, Motions of, Vomer, 77 87 91 144 INDEX. 519 Vertehral Ligaments, .. . . . 265 Vincula Accessoria, . . • . 425 Vastus Externus, . . . ... 444 Vastus Internus, ..... 444 Wrist, Articulations of, ... 291 Zygomaticus Minor, .... 369 Zygomaticus Major, .... 369 END op vol. 1. •/ / / / i y »* * / // ; «- •>'■/, 4 *. 7<_. sf^ 16 07® 6BML. oanogo national library of NLM 032014^ t hSSH Us pHBvMPO 9BB3BQBpBOC3BC3SBS M3& 1* SwSsH ■m ■hm SHmCB WMM UuuiwuwCiBMBi MIS ' NLM032044666