Meckel1812-1 Anatomy 2-12

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Meckel JF. Handbook of Pathological Anatomy (Handbuch der pathologischen Anatomie) Vol. 1. (1812) Leipzig.

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Handbook of Pathological Anatomy Volume I (1812)

Section XII. Of The Accidental Formations

§ 451. The accidental formations(l) are produced sometimes by a peculiar fluid effused expressly to give rise to them, sometimes by precipitation and crystalization, in accordance with the laws of chemical affinity, in a secreted fluid, the chemical composition of which is somewhat changed. The calculi are developed by the second mode ; to the first belong all other formations, whether primitively connected in their organization with parts already formed, or not.

(1) Besides the treatises on patholog-ical anatomy which have been before mentioned, consult Ludwig, Primæ lineœ anatomiœ pathological Leipsic, 1785. — Conradi, Handbuch der pathologischen Anatomie, Hanover, 1796. — A. clarus, Quœstiones de partibus pseudo-organicis, Leipsic, 1805. — Pinel, La médecine clinique rendueplus précise et plus exacte par V application de V analyse, Paris.— Prost, Ld médecine éclairée par l'observation et l'ouverture des corps, Paris. — I. L. Knoblauch, Dîssertatio quœ continet phænomènorum hominis œgroti expositionem, Leipsic, 1810. — Otto, Handbuch der pathologischen Anatomie des Menschen und der Thiere,. Breslau, 1814. — J. Cruveilhier, Essai sur l'anatomie pathologique en général, et sur les transformations et productions organiques en particulier, Paris, 1816.^ — Rayer, Sotnmaire d'une histoire abrégée de l'anatomie pathologique, Paris, 1810. — Consbruch, Taschenbuch der pathologischen Anatomie, Leipsic, 1820.— See also the Hôte sur l'anatomie pathologique, by Laennec, in the Journ. de Corvisart, vol. ix. p. 360, and his article Anatomie pathologique, in the Dictionnaire des sciences médicales. See likewise the articles Anatomie pathologique, in the same collection, and in the Dictionnaire abrégé des sciences médicales, the first by Bayle, the second by Boisseau; Martin's work on organic diseases in general, in the Mémoires de la société médicale d'émulation, vol. vii. and Gruithuisen's researches on the essence of inflammation, in the Gazette médico-chirurgicale de Salzbourg (1816, vol. ii. p. 129), in the preface to his Organozoonomie, in his Beytrage zur Physiognosie und Eautognosie, and in his Trait sur le pus et le mucus.

(2) The nutritive action is doubtless changed in producing every alteration of texture; but this opinion is entirely unimportant, because we are totally unacquainted with the nutritive action, unless it be with the appearance, the form, and the structure, of the parts upon which it acts. To say then that an anomaly innutrition is the immediate cause of all alterations in texture, is to say, in conventional language, that the altered tissues change in their structure, their form, their appeara,nce, and not to resolve, or in any way to conceal, an insoluble diflBculty. Our author on this topic follows his master Reil, to whom also belongs the merit of placing in the organization, in the organic matter, the origin of all the physiolo

The proximate cause of all alterations of texture is an anomaly in nutrition.(2) However different the productions of this power may be when it is deranged, they are very similar in regard to their origin ; (1)and after a certain time, the differences in several depend either on the nature of the parts within or near which they are developed, or on external and accidental circumstances.

All alterations of texture come from an albuminous substance which very probably is always fluid when it is effused.(2)

Dropsy, that is, the abnormal accumulation of an albuminous fluid, may be regarded as the first step of the organism toward forming new substances.

These fluids are sometimes clear and limpid. They often contain coagulated flakes.

They vary much in regard to their specific gravity, their degree of coagulability, and the respective proportions of their liquid or solid constituent principles, especially in their quantity of albumen. The proportion of the salts on the contrary is nearly the same in all. (3) The serum in ascites, hydropericarditis, hydrothorax, hydrocele, &c., which contains much albumen, is easily coagulated by the acids and by heat. That of hydrorachitis and hydrocephalus is but slightly coagulable, from its small quantity of albumen.

Adhesions sometimes occur between organs normally separated, as those enveloped by a serous membrane, by the coagulation of the effused fluids.

When the coagulation exists only to a certain extent, or when the congestion of the liquid disappears, the parts only adhere.

But when the quantity of the effused liquid is considerable, the organs not only adhere, but are imbedded in a thick layer of coagulated substance ; so that we cannot distinguish them from each other, and are led to believe that some of them, although very large, have entirely disappeared.

gical and patholog-ical phenomena of the living' economy. See his fine memoir entitled Veränderte Mischung und Form der thierischen Materie, als Krankheit oder nächste Ursache der Krankheitszufälle betrachtet, in the Archiv für die Physiolosiie, vol. iii. 1799, p. 424. . _ F. T.

(1) This proposition is true, inasmuch as inflammation is the occasional cause, if

not the direct creator, (if we may be allowed this metaphorical expression,) of every accidental production. F. T.

(2) The ancients attended to accidental formations only to investigate the proxi mate cause, and to point out their symptoms ; some of the moderns have attended particularly to describing them, others to determine the morbid alteration which creates them. Heretofore they have been attributed to alterations of the lymph, the blood, or of both of these at the same time ; at present they are considered as the result of a change in the organic texture. Some endeavor to trace their relations of resemblance and of continuity, and their differences from the primitive tissues, while others attempt to place them in one or another order of vessels. Thus Broussais thinks they depend on a change in the organization of the white or of the red vessels, or of both. Meckel goes so far (as we have seen) as to assert that they originate in the exhalation and the coagulation of an abnormal albuminous liquid. The dissections and the preparations of the accidental tissues have not as yet been either numerous enough or sufficiently delicate for us to adopt any of these opinions. The time has not yet come to establish on a solid foundation the connections and the natural relations of these accidental formations. All that we can do is to investigate the composition, the texture, the varieties, and to determine the morbid state which is the first condition of their formation ; so that pathological anatomy is yet in its infancy. F. T.

(3) Marcet,'in the Med. chir. trans., vol. ii. p. 380, 381. — Bostock, ibid. vol. v.

The alteration in nutrition which produces this ultimate union is more serious than that by which the fluids are only accumulated. This state is termed inflammation (§ 126).(1)

The connecting substance varies in quality and consistence ; it not unfrequently ossifies. This is the origin of most ossifications, especially those between the corresponding surfaces of the serous membranes, appearing sometimes in the form of layers, and much more rarely as filaments. The organs surrounded by this coagulation are usually healthy, or at least if they are sometimes slightly changed, we must attribute it to compression. Very solid whitish coagulations, in which vre can scarcely trace any texture, are generally called steatoma or sarcoma.

Most probably all tumors originally assume this form. Analysis demonstrates that they are composed almost wholly of albumen. (2)

The abnormal formations generally adhere more or less intimately to the parts near which they are formed. This remark however is not true of all, for some are perfectly loose ; ‘ this is particularly the case with the fibrous concretions which appear in the vascular system, or the polypi, and also with several cartilaginous or bony substances found in the cavities of the serous membranes, the calculi, and the intestinal worms. Most of these productions are at first connected with the adjacent parts, or are excrescences of them ; this is not the case with the intestinal- worms and calculi, for they certainly are not formed in the midst and at the expense of a fluid.

§ 452. If we carefully examine the relations of situation between the alterations of texture and the organs, it is proved that they result from the change of the normal substance of these organs into another substance more or less different, or that a foreign body forms either within or without the organ, which sometimes, from its mechanical influence, destroys the primitive organ to a greater or less extent, and sometimes causes it to increase more or difference, however, is more apparent than real; at least it M^ m i di^4y»i a -thR exte

(1) We have seen before (p. 137) that Meckel considers infiammation or an analogous act as the principal mode in which all regular or irregular formations, that is, all accidental tissues, whether analogous to those in the organism or not, are produced, and that he considers inflammation as situated in the capillary system. Broussais, in his Histoire des phicgmasies chroniques (Paris 1808), considers pain, swelling, redness, heat, gangrene, induration, suppuration, ulceration, tubercles, lardaceous tumors, cancer, marasmus, dropsy, &c. &c. as the effects of inflammation, In the second edition of his Examen (Paris, 1821) he asserts that cartilaginous, osseous, aud calcareous formations, melanosis, schirrus, tumors, cancers,encephaloid, and tubercles, are produced by inflammation. But bethinks that, in orderte the production of many if not all of these alterations, inflammation of the white.vessels must be complicated with that of the red vessels, with inflammation properly so called ; he terms the former sub-inflammatiou ; this, he asserts, attends every chronic inflammation, and causes all chronic alterations in texture. This consonance of opinion between the French pathologist and the German anatomist favors their theory.

F. T.

(2) Vauquelin, in the Journal de médecine, after the history of a steatoma which filled most of the cliest. — Dissection of an albuminous concretion which was found in the cavity of the thorax, by Wardrop, in the Edin. Med. and surg. Journ. vol. ix. p. 11.

nor, that is, its form.(l) In fact, in the second place, the accidental substance is uniformly blended with the normal substance, or the latter is more or less changed into it ; in the former case it forms insulated and distinct depositions : but this state essentially consists in the production of a substance different from the abnormal tissue, either by an alteration, a derangement, or an anomaly of nutrition, also under whatever form this new substance appears, even when it is inclosed in a cyst which separates it from the normal substance, whether this cyst has appeared before it, and has secreted it, or whether its formation was consecutive to its own and purely accidental.

§ 463. All alterations of texture may then be regarded as new formations, which are sometimes repetitions of those already existing in the normal state, and are abnormal only from the place where they appear, and sometimes are substances wholly foreign to the organism. The latter are somewhat analogous to the normal tissues ; hence for a long time they were called by the same names as the latter, which some moderns still preserve ; but the analogy being very slight, we have no right to consider all the new and morbid formations as repetitions of the normal formations. (2)

We have thought it more convenient to refer the history of the first kind of formations already mentioned (§ 40.) to that of the regular tissues of which they are repetitions, since there are but trifling shades between the phenomena of their production and those of the regeneration of the organs, especially of some of them, as the bones. We shall here mention the details of the others, although we have briefly considered them when treating of each of the regular tissues in which they can be developed. Farther, these two kinds of accidental tissues often exist together, so that it is very common to find different abnormal productions existing simultaneously. There seems to be some regularity in this respect, for there are certain accidental productions more frequently associated than others ; in this respect the different substances are sometimes perfectly distinct, and placed at the side of each other in masses of various sizes, and they are sometimes divided into such small portions, and so intermixed, that they seem to form a new and special tissue.

§ 454. The classification of the perfectly new tissues is very difficult, both from the uncertain marks by which the} are recognized, and the distinctions between the different species, and also from the modifications which they present acccording to the different organs in which they are developed, and from the frequent instances in which several new formations entirely different from each other co-exist. In regard to some tissues, we cannot positively decide whether they are simple excrescences, or partial enlargements of the substance of the organs, or finally formations entirely new. ' Such are particularly the polypi of the mucous membranes.

(1) The untility,and the foundation of this distinction between the change of a primi tive into an accidental tisssue and the production of the latter in a primitive tissue, have already been mentioned. These two kinds of development seem to occur in many cases. The distinction however is not so important as would seem at first view, since it is so difiBcult to determine it. P. T.

(2) As has been done recently by Fleischmann, {Leichenqffungen, 1815, p. Ill, 112,) who certainly goes too far when he contrasts sarcoma with muscle, steato-sarcoma with fat and muscle, the pancreatic sarcoma of Abernethy with the pancreas, and his medullary sarcoma with the medullary substance of the brain. Dumas (Mém. sur les transformations des organes, in the Journal de Sédillot, vols, xxiii. ■and XXV.) had already considered, in an analogous but more ingenious manner, all morbid alterations of the organs as changes of these same organs into each other. This hypothesis has long been expressed by the names of most tumors and by the theory imagined to explain them (Plenk, De tumoribus, Vienna, 1767).

We may, however, admit three kinds of abnormal formations, which are connected with the organs in the same manner as the organs themselves ; 1st, the tuberculous tissue ; 2d, the schirrous tissue ; 3d, and perhaps ihe jungous tissue.

Beside these three, Abernethy(l) admits, 1st, a pancreatic sarcoma, which seems to be only a modification of accidental fibro-cartilaginous tissue, determined by the nature of the parts in which it is developed ; 2d, a mammary sarcoma and a medullary sarcoma, which are very similar to the encephaloid tumor of Laennec. The melanosis of the latter scarcely differs from his encephaloid tumor. The latter may be united to the tuberculous, tissue, and the melanosis to the fungous tissue, which perhaps is only a modification of the schirrous tissue. (2)

§ 455. The tuberculous tissue, the tuberculous or scrofulous formations, and the schirrous, cancerous, or carcinomatous tissue, are similar in certain respects, (3) and different in others. (4) It is on account of their relations with each other and with the other abnormal formations, that the terms tubercle and schirrus are employed in so general a manner, and often for each other, when we would designate those abnormal productions, which, when they inclose a liquid, do not appear in the form of cysts. It is thus that many pretended cancers of the uterus are nothing but fibrous tumors.

The common characters of these two alterations are :

They vary in hardness and have a grayish color. They become harder by the action of acids and heat. In time they soften and become fluid.

The following are their characteristic marks :

The tuber cles{5) are homogeneous, pale white, sometimes yellowish, and opaque. They change into a wlrite and friable mass, then into nn unctuous fluid, in which float small, irregular, grayish, cheeselike films. They appear as rounded bodies, sometimes inclosed in a cyst, or as irregular masses which pervade most of the part in which they are developed.

(1) Sarg, observ. on tumors^ London, 1814.

(2) Laennec divides those tissues which are unlike those in the normal state into

tubercles, encephaloid tumors, schirrous tumors, melanosis, cirrhosis, sclerosis, and squamous tissue. His remarks on these different organic alterations may be found in the Bulletin de la faculté de médecine, Corvisart's Journal dc médecine, his article Jblncephaloidc in the Dictionnaire des sciences médicales, and his work on Auscultation. ,

(3) Bayle, Sur les indurations blanches des organes, in the Journ. de méd. vol. ix. p. 285.

(4) Stark, in the Med. communicat., London, 1784, vol. i. no. 24. — Bayle, in the Journ. de méd.

(.5) G. Stark, Observations clinical and pathological, Fjondon, 1784. — Reid, Essay on the nature and cure of phthisis pulmonalis, London, 1782. — Bayle, Remarques sur les tubercules ; in Journal dc Corvisart, vol. vi. 1803, p. 3. — Id. Remarques sur la dégénérescence tuberculeuse non enlajstée du tissu des organes, vol. ix. 1805, p. 427, vol. X. p. 32.— Id. Recherches sur la phthisie pulmonaire, Paris, 1801. — J. Baron,

The schirrous tumours are formed of two substances, one white, fibrous and opaque, which forms a network, the other semi-transparent, a little brilliant, bluish or greenish, rarely white or red, which is inclosed in the spaces of the network. They change into an ichorous pus which corrodes the skin and gives rise to fungous tumor and ulcers, the edges of which are turned over.

The tuberchs are situated principally in the lungs and in the lymphatic glands, particularly those of the mesentery, of the mucous membranes, of the intestinal canal, especially in the last stages of tubercular phthisis, more rarely in the liver, the spleen, the testicles, the kidneys, and the muscles.

The scliirrous tumors are developed particularly in the glandular organs, especially in the mammary glands, the uterus, the prostate gland, the intestinal canal, and the skin, whence they extend also to the lymphatic glands, and to all the adjacent parts.

The fungus hematodes of Hey, the spongoid inflammation of Bums, the melanosis of Laennec,(l) are in fact one and the same formation, which differs from the preceding onlyin its greater softness and blackish color. It is however so allied to schirrus in structure and progress, that it has been termed soft cancer. (2)

§ 456. The abnormal formations of which we have spoken may be considered as integral parts of the organism, as they are so intimately connected with the other organs. Some however are unconnected with it and are loose, but derive their nourishment from it* These are the intestinal worms, or the entozoa, some of which live in separata cysts, and others in direct contact with the substance of the ‘organs.

The lowest formations of this kind are loose vesicles, with thin, semitransparent, and round parietes, which are perfectly homogeneous, and filled with a serous, thin fluid ; they vary much in size and number, and are developed both in the substance of the organs and in the normal and abnormal cavities. These vesicles probably should be regarded not so much as animals, but as membranes analogous to those of the ovum. They have been termed /ii/darids, and by Laennec, acephalocysfes.{Z)

An inquiry illustrating the nature of tuberculated accretions of serous membranes and the origin of tubercles and tumors in different textures of the body, Zondon, 1819.

(1) Hey, Onfongus hÅ“matodes ; in Obs. on surgery, London, 1814, cli.vi. — Wardrop, On fungus hÅ“matodes, Edinburg-h, 1809. — Burns, Spongoid inflammation; in Lectures on inflammation, Glasgow, 1800, vol. i. p. 302.— Laennec, Su.r les melanoses ; in Bullet, de l'éc. de méd. 1806. — Breschet, Considérations sur une altération organique, appelée dégénérescence noire, Paris, 1821.— Id. Supplément aux considérations sur la mêlanose ; in Revue médicale, vol. vii. p. 79. — Heusinger, in Lis Recherches sur la production accidentelle de pigment et de carbone Sans le corps humain Eisenach, 1823, considers the melanosis, from the analyses made by Barreul and Lassaigne, as a deposition of the coloring matter and of the fibrin of the blood.

(2) Maunoir, Alémoire sur lesfongus médullaire et hématode, Paris, 1820.

(3) Lüdersen, De hydatidibus, Gottingen, 1808. — Laennec, in Bulletin de lafac, de médecine, 1812, p. 49. — See also Rodet, Observations sur les hydatides ; in Journal

They occur principally in the liver, whence they perhaps pass into the abdominal cavity, the ovaries, the kidneys, the brain, the lungs, and the testicles. However they have been found in every organ, although rarely.

After the hydatids come the vesicular leorms, which are contained in special cysts. Sometimes there are developed in their vesicle several organs, which perhaps should be considered as parts of one whole {echinococcus), rather than as separate animals, and to which many cases of acephalocystes are doubtless referred ; sometimes the vesicle almost entirely disappears or is seen only at the posterior extremity of the body in the form of a caudal pouch {cijsticercus), even as in the superior animals, the envelops of the ovum are connected with the lower region of the body. The former of these vesicular worms appears in the same places as the hydatids, and the second principally in the cellular tissue, the muscles, and the brain.

The other intestinal w'orms have an existence still more independent. They are not inclosed in sacs distinct from their proper substance, and we cannot trace the organs which have formed them. In most of them, especially in the Jilaria, the hamularia, the irichocephali, the ascarides, the strongyli, and the iÅ“niÅ“, the greatest dimension is their length. At the same time they are also round, except the tÅ“niæ, which are very thin and flat. Some of them, the dislomata and the poly stomata, are short, broad, and flat. They live principally in the intestinal canal ; this at least is the case with the ascarides, the trichocephali, the tæniæ, and the distomata. Others are met with in the cellular tissue, under the skin and the muscles {filaria), in the bronchial glands {hamularia), the ovaries and the Fallopian tubes polystoma), in the kidneys and the bladder {strongylus) ,

compl. du Diet, des sc. medic., vol. xvii. p. 123. — G. Jæg'er, Beobachtungenüber Hulsenwürmur im Menschen und einigen Smiglhieren ; in Meckc), Dcutches Archiv fdr die Physiologie, vol vi. p. 495. — J. P. M. De Olfers, Commentarius de vegetativis et animatis corporibus in corporibus animatis reperiundis, Berlin, 1816. H. Cloquet, Faune des médecins, vol. i. Paris, 1822. — Rendtorff, De hydatidibus in corpore humane, praesertim in cerebro, repertis, Berlin, 1822.

(1) Among tbe peculiar to man, the tricocephalus dispar, the oxyurus ver micularis, the ascaris lumbricalis, the botryoccphalus latus, and the tÅ“nia solium, are the only well-determined species hithertopbserved, which live in the intestinal canal. Blainville has applied the term nettorhyncus io another intestinal worm, which has been long observed, but which has been neglected by zoologists. Cloquet has described another as the ophiostoma Ponthieri, which pei haps is only a gordius aquaticus. Of the entozoa which do not inhabit the intestinal canal, we find the filaria mcdinensis under the skin, but perhaps it come.from without. The hamularia svheompressa has been found in a bronchial gland ; It is a doubtful genus, although Cloquet states that he has observed a new species of it, which had caused very serious nervous affections. The strongylus gigaslives in the kidneys and perhaps also in the adjacent muscles. The distoma hepaticum inhabits the gall-bladder and perhaps the liver. The polystoma pinguicola has been found only once in the fat around the ovarjr of a young peasant girl ; it is a doubtful animal. The cysticercus ccllulosus inhabits the cellular tissue of the muscles and of the brain ; Rudolph! has remarked that it is very common in man, although Bremser asserts the contrary. The cysticercus ccllulosus, Jischerianus, dicysius, and albo-punctatus, liave also been found in man. The echinococcus hominis occurs in thv cysts of hydatids, as do also the accphalocysta ovoidca, suTculigera, granulosa and racemosa. All other intestinal worms mentioned by authors are either larvÅ“ of hexapodous insects, or worms of rain-water or parts of

Of these worms, the echinocci hominis, the tænia solium, the tœnîa lata, and some other species, as yet but little known, the polystoma pinguicola, the hamularia subcompressa, the ascaris vermicularis, and the filaria medinensis, are peculiar to man, the others are met with also in most of the mammalia, but only in animals.

§ 457. The calculi{l) are formed in the secreted fluids(2) by a chemical process, by precipitation and crystalization.

plants. Bremser has termed them collectively pseudo-helminthia, which is not very convenient, because many of these animals, particularly the ditrachyceros rudis of Sulzer, and perhaps some others, all in fact doubtful, resemble at least the entozoa.

The history of the animals developed in the bodies of other animals is as yet not much advanced, and hitherto has not been considered in a truly philosophical point of view. Thus, for example, not to mention the discussion which has continued since Redi, on the cause of their production, that is, on their mode of formation, although we cannot doubt that they are created, if not by a real inflammation, at least by a state very similar to it, we have separated from the considerations in regard to these animals, those which relate to the history of the entozoa, that is, from the animated parasites which develop themselves, and live on the surface of living animals. Even the history of the latter, although it is so evidently connected with that of the entozoa, has been neglected. We wish to speak particularly of the pediculi, which exist in such numbers that nosologists have formed a disease called phthiriasis. The great multiplication of these parasitic animals, in crusta lactea, tine^ plica, induce us to believe with Bremser, that in certain cases they are formed primitively. This manner of production is even the only one which can be admitted in certain cases, even when the pediculi alone form the contents of certain tumors, of which Rust has observed a remarkable instance cited by Bremser {Sur les vers intestinaux de l'homme, p. 97), and to which may be attached an interesting note of Bory of Saint Vincent, on a species of ascarides which lives in the human body {Journal compl. du diet. des. sc. méd. vol. xix. p. 182). Another circumstance favorable to this theory is the specific difference which seems to exist between the pediculua of the white man and that of the negro (Fabricius, Systema antliatorum, p. 340), and which resembles the difference observed between the kinds of ténias peculiar to the inhabitants of the north of Europe and those observed in the people of the south.

Finally, we must adduce together with these facts the vegetable parasites of the class of mushrooms which have been found in animals, and which arise undoubtedly from the same source ; physiologists have nev'er attended to this last phenomenon. We however have two authentic instances of it, observed one, by A. C. Mayer, {Deutsches Archiv far die Physiologie, vol. i. p. 310), the other, by G. P. Jægcr {same journal. vol. ii. p. 354). P. T.

(1) Walter, Anatomisches Aluseum, Berlin, 1796. — Wendelstaedt, Ueher Steine im menschlichen und thierischen Körper ; in his Aledicinisch-chirur gische Wahrnehmungen, Osnabrück, 1800, vol. i. p. 156-264. — Fourcroy, Sur le nombre, la nature et les caractères distinctifs des différons matériaux qui forment les calculs,les bezoards et les diverses concrétions des animaux ; in Annales du Aluséum, vol. i. p. 93. — Marcet, On the chemical nature of calculi. — Consult also, 1st. Onurinary calculi; Tenon, Sur la nature des calculs; in Mém. de Paris, 1764. Link, De analysi urincc et originà calculorum, Gottingen, 1788. — Wollaston, On gouty and urinary concretions ; in Phil, trans., 1797, p. ii. p. 386. — Pearson, Experiments and observations, tending to show the composition and properties of urinary concretions; same journal, 1798, p. i. p. 15. — Brande, On the differences of calculi dependent on their formation in different parts of the body, same journal, 1808, p. 223-248. — Prout, On calculus disorders, with notes, by S. Colhoun, Philadelphia, 1828. — 2d. On biliary calculi ; Morand, Sur des pierres de fiel singulières ; in Além. de Paris, 1741, p. 355.— SÅ“mmerring, de concrementis bilicarüs, Erfurt, 1795. — Mosovius, De sede calculorum animalium, eorumque imprimis biliarium, origine etnaturâ, Berlin, 1812. — 3d. On intestinal calculi ; J. F. Meckel, lieber die Concretionem im menschlichen Darmkanal ; in Archiv für die Physiologie, vol. i. p. 454r-467. — 4th. On lacrymal calculi; Walter, Sur les dacryolithes on calculs lacrymaux ; inJourn. compl. des sc. méd., vol. vii. p. 51. — 5th. On venous calculi ; Tiedmann, Sur les calculs qui se rencontrent dans l'intérieur des veines ; same journal, vol. iii. p. 38.

(2) In regard to the intestinal worms of man see the classical work of Rudolphi, Entozoorum hist, nat., Amsterdam, 1808-1810. — Bremser, Traité zöologique et physiologique sur les vers intestinaux de l'homme, trans. by Grundier, with notes by Blainville, Paris, 1824.

Sometimes, but this is very unusual, they are developed accidentally around a foreign body, which has been introduced into the organ and serves as a nucleus. Sometimes, and most commonly, they form in consequence of a change in the chemical composition of the liquid, in the midst of which they are precipitated, probably also in that of the common nutritious fluid, and generally because all the functions are deranged.

They differ so much in form, number, chemical composition, and color, that it is almost impossible to refer their history to any general head. All that we say on the subject is reduced to the following particulars ;

1st. They are primitively loose ; they rarely adhere to the parts in which they are found.

2d. Each liquid has its calculi more or less peculiar in regard to chemical composition, but which are similar in some of their constituent principles.

3d. Then' constituent principles sometimes do not exist in the liquid in which they are found.

4th. In most of the fluids at least we find not only one but several kinds of calculi.

5th. They are sometimes single and sometimes compound, their different constituent principles are sometimes intimately blended in all parts of the calculi, and sometimes form so many different layers.

6th. They are usually developed around a nucleus.

7th. Their number is almost always inversely as their size.

8th. They are generally solid and rarely hollow.

9th. Their structure is radiated or lamellar. .

10th. They are sometimes smooth and sometimes rough.

11th. They generally appear at mature age, which is not invariably the case, for they are sometimes found even in the fetus.

12th. Certain liquids, as urine and bile, have a greater tendency to produce them than others, but their formation is favored by external circumstances so, that the same kind of calculus is more common in some parts of the body than in others.(l)

(1) Here should be referred all those abnormal productions termed by pathologists accidental ossifications, which, attached to the body by no organic connection, and presenting nono of the characters which distinguish the bones, cannot be referred to the latter unless we listen to the insidious suggestions of a purely external analogy.

F, T.

SOURCES.

Before treating of general anatomy, we mentioned the principal sources, which, at the same time, appertain in part to descriptive anatomy : here we notice the principal general works which are connected with descriptive anatomy, and which contain general descriptions of the different organic systems, which are however proportionally shorter.

A. GENERAL WORKS,

I. HISTORY OF ANATOMY.

P. J. Hartmann, DisquisUiones hisioricæ de re anatomica veicrum, Kcenigsberg, 1693.

Portal, Hist de I'anaf. et de la chirurgie, Paris, 1770—1773.

Lauth, Hist, de l'anat., Strasburg, 181-5.

II. CATALOGUES OF BOOKS AND DICTIONARIES.

J. Douglas, Bihliographiœ anatomicæ specimen, s. catalogus omnium pene auctorum qui ab Hippocrate ad Harveuni rem anatomicani ex professa vel obiter scriptis illustrarvnt, London, 1718.

Haller, Bibliotheca anatomica, qua scripta ad anatomeii et physiologiam facientia, a rerim initiis recensentur, Zurich, 1770-1777.

Heister, Änatomisch-chirtirgisches Lexikon, Berlin, 1753.

Tarin, Dictionnaire anatomique, suivi d'ime bibliothèque anatomique et physiologique, Paris, 1753.

III. SMALL TREATISES ON DIFFERENT SUBJECTS,

Corvinus, De dignitate, jucunditate, et usu anatoniiæ, Leipsic, 1611.

Fabiicius Hildanus, Anatomiœ prastantîa et uiilita^, Berne, 1624.

B. S. Albinus, De necessitate studii secandi, Francfort, 1683.

E. Stahl, De sérié et usu inventionum anatomicarum. Halle, 1705.

Dern, De anatomes in praxi usu, Halle, 1707.

J. J. Rau, De meih. anatomen docendi et discendi, Leyden, 1713.

B. S. Albinus, De vera via quæ ad corp. hum. cognitioncm ducat, Leyden, 1721.

A. Walther, Densu etprœsiantia analomes scieniiœ, Leipsic, 1723,

Coschwitz, De studii anatomiœ præstantia ei utilitate, Halle, 1727.

Heister, De anatomes necessiiate, Helmstadt, 1727.

Hebenstreit, De medici cadavera secantis religione, Leipsic, 1741.

Munnicks, De summis quas analome habet deliciis, Groningen, 1771,

Bonn, De simplicitate naturœ anatomie or um admiratione, chirurgorum imilalione digna, Amsterdam, 1771.

S'Gräuwen, Oratio de anatomiœ pathologicœ utiliiatel et^ necessitate, Groningen, 1771.

Sandifort, Oratio de circumspecio cadaverum examine, opiimo practicœ medicœ adminiculo, Leyden, 1772.

M. Girardi, De re anatomica oratio, Parma, 1781.

C. Siebold, Rede von den Voriheilen, welche der Staat durch anatomische Lehranstalten gewinnt, Nuremberg, 1788.

Rougemont, Rede ueber die Zergliederungskunst, Bonn, 1789.

D. G. Silbermann, De promovendis anatomiœ pathologicœ administrationibus, Halle, 1790.

Roeschlaub,BMn'g‘ÉS ueber Jhiaiomie,\i\ ÜiQj\Iagaz.zur Vervollkommung der Medicin, vol. vi. p. 401, Francfort, 1801.

F. Schelling, Ueber das Studium der JMedichi und der organischen JYaturlehre ueberhaupt, in the Vorlesungen ueber die Æeihode des akademischen Sludiums, Tubingen, 1803.

Index rerum musei Ticinensis ; accedil ScarpÅ“ ora/ro, Padua, 1804.

Froriep, Einige Worte ueber den Vortrag der Anatomie auf Universitäten, Weimar, 1812. — Idem, Ueber die Anatomie in Beziehung aif Chirurgie, Wiernar, 1813.

IV. TREATISES AND MANUALS.

A. THE NORMAL STATE OR THE NORMAL AND TUE ABNORMAL STATE.

Galen, De anal, adminislraiionibus, lib. ix., and De usu partium, lib. xvii. in Opp^ omn. vol. ii. Vienna, 1597.

Mundinus, Analomia emendata, Marburg, 1540.

Berengarins, Carpi, Commentarii cum amplissimis adnofationibus supra anatomiam JVhmdini, Bologna, 1521. Idem, Isagoge in anatomiam corp. hum., Bologna, 1522.

Riverius, De dissectione partium corp. hum., lib. iii. Paris, 1545,

Vassaeus, In anatomen corporis Immani iabidœ., iv. Paris, 1553.

J. Sylvius, Isagoge in libros Hippocratis et Galeni anatomicos, Paria, 1558.

Vesalius, De corp. hum. fubrica, lib. vii. Basle, 1545.

Gemini, The anat. of the inward paris, London, 1559.

Colombo, De re anatomica, 1. xv., Venice, 1559.

Valverde, Anat, del corpo umano, Rome, 1560.

Coiter, Extern, ei intern. j)rincip. hum. corp. partium tahulœ, Nuremberg, 1573.

F. Plater, De corp. hum. structura et tmi, lib. iii., Basle, 15S3. Piccolomini, Anotomicæ prœlectio7ies, Rome, 1586.

Guidi, 0pp. omn., Erfort, 1668.

Varolius, Jlnatomia, s. de corp. hum. resolutione, 1. iv., Erfort, 1591. Bauhin, De corp. hum. fabrica, Leyden, 1590. Idem, Inslitutiones anatom. .! Francfort, 1592. Idem, Theatrum anatomicum, Francfort, 1605.

Riolan, Anthropographia, Paris, 1618. Idem, Enchh-idion anatomicum et pathologicum, Paris, 1648.

Spigelius, Deco7'p. hum.fahdca, 1. x. Venice, 1627.

T. Bartholinus, Jlnatomia reformata., Leyden, 1641.

Veslingius, Syntagma anatom., Padua, 1641.

Highmore, Corp. hum. disquisitio anatomica, Hague, 1651. Marchettis, Compendium anatomicimi, Padua, 1652.

Lyser, Cutter anatomicus, Copenhagen, 1653.

Habicot, La semaine, ou Pi-atique anatomique, Paris, 1660.

Zeidlern, Somatotomia anthropologica, Prague, 1686.

Collins, System of anatomy, London, 1685.

Diemerbroek, 0pp. omn., Utrecht, 1685.

Taury, JYouv. anat. raisoiinée, Paris, 1690.

Verheyen, Anat. coi'p. hum., Louvain, 1693.

Keil, Anat. of the hum. body, London, 1698.

St. Hilaire, Anat. du corps hum., Paris, 1698.

Fantoni, Brevis manuductio ad hist, anat., Turin, 1699.

Bartholinus, Specimen hist. anat. part. corp. hum., Copenhagen, 1701. Cheselden, Anat. of the hum. body, London, 1713.

Dionis, Anat. de Vhomme, Paris, 1716.

Heister, Co^npendium anatomicum, Altdoif, 1717.

Hellwig, JVosce te ipsum, Erfort, 1720.

Kùlmus, Tabulai anatomicce, Amsterdam, 1732.

Winslow, E.rpos. anat. de la struct, du corps hum., Amsterdam, 1732. Palfyn, A^iat. chirurg., Paris, 1734.

Cassebohm, JMethodus secandi, Halle, 1740.

Lieutaud, Essais anatomiques, Paris, 1742.

A. Schaarschmidt, Anatomische Tabellen, Berlin, 1746—1750.

Verdier, Abrégé de l'unat. du coi'ps hum., Brussels, 1752.

KraptF, Naturspiegel, Basle, 1761.

Sa,batier, Traité complet de l'ancd., Paris, 1772.

Plenk, Primæ lineœ anatomicce, Vienna, 1777.

Leber, Prœlectiones anatomicœ, Vienna, 1778.

Mayer, Beschreibung des ganzen inenschlichen Koerpers, Berlin, 1783— 1794.

Loder, Anatom. Handbuch, vol. i. 1788.

Hildebrandt, Lehrbuch der Anatomie des JMenschen, Brunswick, 1789 -1792. â–  '

Soemmerrin^; Vom Bau des menschl. Koerpers.

Caldani, In0tj:^lio7ies anatomicœ, Venice, 1791.

Wiedemaivi, &mdbuch der Anatomie, Brunswick, 1796.

Vol. I. • 46

J. Bell, The anal, of the hum. body, Edinburgh, 1797.

Boyer, Truité complet de I'anat., Paris, 1797.

Bichat, Traité de Vanat. descript., Paris, 1801—1803.

Hempel, Jhifangs gründe der Anatomie, Gottingen, 1802.

Hesselbach, Anleitung zur Zergliederungskunde des JVIenschen, Rudolstadt, 1805.

Fattori, Guida alla studio delV anatomia umana, Pavia, 1807. Langenbeck, Anatom. Handbuch, Gottingen, 1806.

Mayer, Anatom. Handbuch, Vienna, 1812.

Monro, Outlines of the anat. of the hum. body, Edinburgh, 1812. Gordon, A system of human anatomy, Edinburgh, 1815.

H. Cloquet, A system of human a^iatomy, trans. by R. Knox, Edinburgh, rep. at Boston, 1831.

Marjolin, Æanuel d'anatomie, Paris, 1814.

Boek, Handbuch der praklischen Anat. des menschl. Koerpers, Meissen, 1820.

J. Cloquet, Anat. tie Vhomme, Paris, 1822.

Bayle, Petit manuel d'anat. descript., Paris, 1823.

C. Wistar, A syst. of anatomy, 5th edit., Philadelphia, 1830.

W. E. Horner, A treatise on general and special anatomy, 2d edit., Philadelphia, 1830.

B. THE ABNORMAL STATE.

Bonetus, Sepulchretum, s. anat. pract., Geneva, 1700.

Morgagni, He causis et sedibus niorborum, Venice, 1761.

Lieutaud, Historia anatomica medica, Paris, 1767.

Ludwig, Primœ lineæ anat. path., Leipsic, 1785.

Baillie, The morbid anat. of the most riirp. parts of the hum. body, London, 1793.

Conradi, Handb. der j^athol. Anatomie, Hanover, 1799.

Vetter, Aphorismen aus der pat hol. Anatomie, Vienna, 1803.

Voigtei, Handbuch der p>atholo gischen Anatomie, Halle, 1804-1805. Meckel, Hanb. derpathol. Anatomie, Halle, 1812-1816.

Otto, Handbuch derpathol. Anatomie, Breslau, 1813.

W. E. Horner, A treatise on path. Anatomy, Philadelphia, 1827.

COPPERPLATE ENGRAVINGS.

I. NORMAL STATE. a. In respect to the external form of the body.

A. Durer, Vier Buecher von menschlicher Proportion, Nuremberg, 1528.

Genga and Lancisi, Anatomia per uso et intelligenza del disegno ricercata non solo sugV ossi e rnuscoli del corpo hurnano, rna dimostralo ancoru su le statue antiche priù insigni di Roma, Rome, 1691.

b. In respect to the structure of Ike wholebody.

B. Eustachius, Tabula, anatomica, Rome, 1714.

C. H. RvfF, Descript, anat. de toutes les parties du corps humain, exprimant au vif tous les membres, rédigée en tables, Paris, 1543.

J. R'emmelinus, Catoptrum microscopicum, suis aeri incisis visceribus spendens, Augsburg, 1619.

Casserius Placentinus, Tabula anat., Venice, 1627.

Bidloo, Anatomia hum. corp., centum et quhique tabidis demonstrata, Amsterdam, 1685,

Welchius, Tabula anat., tiniversam corp. hum. fabricam perspicue atque succincte exhibentes, Leipsic, 1697.

Cowper, Änatomia corporum humanorum, CXIV tabulis ad vivum expressis illustrata, Leyden, 1739.

Petriolusand Berrettinus, Tabula anat., Rome, 1741.

Gautier, Exposition anat. de la struct, du corps hum. en vingt plan'ches imprimées avec leur coideur nat., Marseilles, 1759.

Mayer, Anatomische Kupfertafeln, Berlin and Leipsic, 1783—1794.

J. C. Loder, Tabida anatonricce, 1794-1803.

Rosenmüller, Chirurg, anatom. Abbildungen für Aerzte und Wundaerzte.

II. ABNORMAL STATE.

A complete work, exhibiting even generally all deviations of the external form and of the texture of the whole and of the parts of the human body, is still wanting, although we have excellent figures of the most abnormal deviations.

We find a considerable number of the cblferent anomahes figined in Baillie, A series of engravings accompanied ivith explanations, ivhich are intended to illust. the morbid anat. of some of the most imp. parts of the hum. body, London, 1799.

Sandifort, JVLuseum anat. academia, Leyden.

B. DIFFERENT ANATOMICAL WORKS, BOTH ON THE NORMAL AND THE ABNORMAL STATE.

I. PERIODICAL WORKS.

Reil, Archiv für die Physiologie, Halle, 1795.

A. F. Heckler, Æagazin fur dicjjathol. Anat., Altona, 1796. Iserflamm and Rosenmüller, Beitraege fur die Zergliederungskunst, Leipsic, 1800.

P. F. Meckel, Journal f. anatom. Varietaeten, Halle, 1802.

J. F. Deutches Archiv f. die Physiol., Halle, 1815.

II. TREATISES WITH AND WITHOUT ENGRAVINGS.

Eustachius, Opuscula analomica, Venice, 1564.

Arantius, Observât, anatomicœ, Venice, 1578.

Goiter, Æiatomicœ exercHaliones ohservatioiiesque varia ad calc. Tabul.

ext. et intern, corp. hum. partium, Nuremberg, 1572.

Plater, JMantissa observationum, Basle, 1614.

Hyeronimus Fabricius ab Aquapendente, Ojyp. omnia anat. et physiol., Leipsic, 1687.

J. Riolanus, Opera anatomica, Paris, 1649.

Fallopius, Observationes anatomica. Idem, Institutiones anatomica. Idem, In librum Galeni de ossibus expositio. In 0pp. omn., Francfort, 1600.

Bartholinus, Hist. anat. Cent. VI., Copenhagen, 1654-1661. Veslingius, Observationes anatomica, Copenhagen, 1664.

Blasius, Observ. medica rariores, Amsterdam, 1677.

Tulpius, Observ. medica, Amsterdam, 1672.

Le Clerc and Mangetus, Bibliotheca anatomica, Francfort, 1668. Kerckringius, Specimen anatomicum, Amsterdam, 1670. Idem, 0pp. omn., Leyden, 1729.

Peyer and Harder, Exer citât, anat. et medic, familiäres, Basle, 1682.

J- J. Harderus, Jipiarum observ. mcd., <$a., Basle, 1687.

Stalpart v. d. Wiel, Observ. var. anatom., Leyden, 1687.

Malpighi, 0pp. omn., Leyden, 1687.

Pechlinus, Observ. phys. med., Hamburgh, 1691.

F. Ruysch, Opera anatomico-medica, Amsterdam, 1691-1742.

Bidloo, 0pp. omn. anat.-chirurg., Leyden, 1715.

Mangetus, Thealr. anat., Geneva, 1718.

Morgagni, Adversaria anatomica, Leyden, 1723. Idem, Epistolœ anatomica diia, Leyden, 1728. Idem, Episi. anatomica XVIII. ad scripta pertinentes celeb er rimi viri A. J\l. Valsava, Padua, 1764. Santorinus, Observ. anat., Venice, 1724. Idem, Tabida XVII. a Girardi édita, Parma, 1775.

Bassius, Obs. anat.-chirurg. -medica, Halle, 1731.

Trioen, Observ. medico-chirurgica, Leyden, 1743.

Haller, Disputationes cmatomica selecta, Gottingen, 1746—1751. Idem, Opera minora, Lausanne, 1762-1768.

Lambrecht, Observ. et oblectat. anaf, Francfort, 1751.

Böhmer, Observ. anat. rarior. fascic., Halle, 1752.

Tabarranus, Observ. anat., Lucca, 1753.

Löseke, Observ. anat.-chir. medica nova et rariores, Berlin, 1754.

P. C. Fabricius, Sylloge observ. anal., Helmstadt, 1759.

Duverney, Å’uvres analomuiues, Paris, 1761.

B. S. Albinus, Annotationes academica, Leyden, 1754-1768.

P. Camper, Demonstrationes anatomico palhologica, Amsterdam, 1761. W. Hunter, Jiledical commentaries, London. 1762. Supplem., 1764.

G. v. Doveren, Specimen observ. academicarum, Leyden, 1765.

Büttner, In vielen Jahren gesammelte anat. Wahrnehmungen^ Koningsberg, 1768.

Eschenbach, Observ. quœclam anat. chir: medic., Rotterdam, 1769.

Siebold, Coli, obseim. med.-chirurg., Wirtfemberg, 1769.

Forlanus, Rar. observ. med. pr. et anat., Venice-, 1769.

Ludwig, abversaria medico-practica,hei^sic 1769—1773.

Insfeld. De lusibus nature, Leyden, 1772.

J. G. Walter, Observ. anat., Berlin, 1775.

Meig, Observ. botan., anat., et physiol., Basle, ' 1776.

E. Sandifort, Observ. anatomico-pathologicæ, 1777—1781. Idem, Exerc. academiccz, Leyden, 1783. Idem, Opusc. anat., Leyden, 1784. Idem, Thesaurus dissertationum, Leyden, 1778.

Azzoguidi, Pallettæ, Brugnoni, Opusc. anatom, select, edit, curavit E. Sandifort, Leyden, 1788.

Rezia, Specimen observationum anat. et pathol., Padua, 1784.

G. Prochaska, Annotat. academicar., Prague, 1784.

Neubauer, Opera anatomica, Francfort, 1786.

J. Hunter, Observ. on certain parts of the animal Å“conomy, London, 1786.

F. A. Walter, Annot. academicœ, Berhn, 1786.

Leveling, Observ. anat. ranores icon, illustr., Nuremberg, 1787.

Monteggia, Fasciculi pathologici, Turin, 1789.

A. J. van Doveren, Observ. pathologico-anatomicæ, Leyden, 1789.

Penada, Saggio J osserv. e memorie sopra alcuni riscontrati 7iell[ ese^'cizio della med. e della anat. pratica, Padua, 1793.

Van de Laar, Observ. chh'urg. obstetr. anat. ined., Leyden, 1794.

Röhler, Beschreibung der phys. und path. Praeparate, welche in der Samml. des Hrn. Hofr. Loder enthalten sind, Jena, 1795,

Portal, Æém. sur la nature et le traitement de plusieurs maladies, avec le p7'écis des expériences sur les animaux vivans et d'un cours de physiol, pathologique, Paris, 1800.

Wrisbergius, Co^nmentationes med., physiol., anat., et obstetr. ,^argmnenti soc. reg., Gottingen, 1800.

Flachsland, Observ. dnatomico-pathologicœ, Rotterdam, 1800.

Rudolphi, Anat. -physiologische Untersuchungen, BerHn, 1802.

Vicqd'Azyr, Å’uvres, Paris, 1805.

J. F. Meckel, Abbandlungen aus der vergleichende^i und menschlichen Anat. und Physiol., Halle, 1806. Idem, Beitraege zur menschl. und vergl. Anatomie, Leipsic, 1808-1812.

Kelch, Beitr. zur pathol. Anat., Berlin, 1813.

Fleischmann, Leichnöffnungen, Erlangen, 1815.

Otto, Seltne Beobachtungen zur Anatomie, Physiologie, und Pathologie gehörig, Breslau, 1816.

III. PLATES.

A. Cant, Impetus jn'imi ancdoinici ex lustratis cadaveribus nati, Leyden, 1721.

Haller, Icon, anatomicar. fasc. VIII., Gottingen, 1743-1756.

Santorinus, Septcmdecim tabtilæ qiiæ nunc primum edidit Girardi, Parma, 1775,

C. F. Ludwig, De cpiarundam œgritudinum hum. corp. sedibus et cuusis tabulœ XVII., Leipsic, 1798.

G. Sandifort, Tabula anatomicœ silum viscerum thoracicorum et abdominalium ah uiroque latere, ut et a posteriori parte dipingentes. Accedit observatio de aneurqsmate arterial, iliacœ internee, rarioris ischiadis nervosa causa, Leyden, 1804.

Cruvelhier, Anatomie pathol. du corps humain, Paris, now publishing.

§ 457. Descriptive anatomy, or the topograjyliy of the human body, is the exact description of the parts which constitute it. It considers, 1st. The human body generally, and its different regions, without regard to the difference of the systems composing it ; it points out the dimensions of the whole body and those of its parts, and also the mutual relations of these parts.

2d. The different systems which compose it, in respect to the situation, the number, the size, and the forms of its parts.

PART I. GENERAL REMARKS ON THE HUMAN BODY

§ 459. We have already stated the special characters of the human body : it only remains to examine,

1st. Its height.

2d. Its division into different regions.

§ 460. The height of man is not the same every where. Like that of all other prganic formations, it depends in some measure on the climate : hence the tallest men are found in the warmest countries, while the shortest inhabit the colder regions. In considering the normal differences which belong to whole masses, we find the height varies from six feet and a half to four feet and a half, so that the mean is between five and six feet ; that the male is a little taller than the female ; and that we may consider as untrue all assertions that nations exist in which the height generally exceeds or is less than these limits. But, although all nations present a certain fixed height, when considered generally and in the mass, indmduals differ much in this respect, sometimes exceeding the common measure, and sometimes falling short •of it. If Ave take individuals into consideration, we find the height of man varies from eight feet to sixteen inches.(l)

In both cases the relations between the different parts of the body de\uate usually from the ordinary rule. Generally the lower extremities of giants are very short ; the superior, on the contrary, are very long : the head also is too small. In almost all dwarfs, the head is too large ; but the relation between the upper and lower extremities is the same as in giants. The cause of dwarfishness is general disease, especially rachitis.

Besides those cases in which we see certain individuals taller than the rest of the species, it sometimes happens that the body prematurely acquhes all the development in regard to height of which it is susceptible. This state, wlrich is characterized also by the precocious appearance of puberty, is almost always attended with a proportional imperfection in the development of the intellectual faculties, and a very short life.

(1) Haller, in his Physiology, mentions several giants and dwarfs. — Bonn {Thés morb. OSS. Hot., Amsterdam, 1783, p. 134-136) has given the dimensions of the skeletons of giants. — Zitterland, De duorum scclectorum, prœgrandium rationibus, Berlin, 1814. — The accounts of men more than eight feet in height are doubtful, or arrive from considering fossil bones of large animals as human bones, or finally depend upon the extraordinary development of the crania from hydro-cephalus.

§ 461. The human body is composed, a, of a right and a left, an upper and a lower', and finally of an anterior and a postei'ior half : we have already mentioned their principal characters (§ 23 — 28) in respect to the analogies and discrepancies, b. It is also divided into three parts, the trunk (truncus), the head (caput), and the limbs (extremitates). These are also subdivided into several regions.

§ 462. The trunk (truncus) comprises three parts : the neck (coU lum), the chest (pectus, thorax), and the belly (abdomen). Each of these parts is composed of some one of the different organic system,s. The chest and the belly are hollow, and their cavities (cava) experience greater or less changes in their figure and their dimensions. These ca-vities contain organs which in the normal state do not adhere to their parietes, except anteriorly and posteriorly, but are in close contact with them, and are called for this reason- the viscera of the chest, of the abdomen, and of the pelvis. The neck has no cavity ; the parts which form it are united together, and with the skin,which covers them all, by mucous tissue, while in the thorax and the abdomen, the skin and the bones, as well as the muscles directly united to the integuments, are separated from the subjacent parts by a proper serous membrane.

The vertebral column forms the base of the Avhole trunk. It is a hollow column composed of bones placed one upon another ; these bones have the same general form, but this form is differently modified in the different regions. It extends-from above downward, in the centre of the posterior face of the trunk, and is covered its whole length backward and on both sides, also forward in the neck and in the upper part of the abdomen, by .muscles which move the vertebral column and the parts attached to it, the head and the limbs, and finally the organs contained in the cavities.

The parietes of the abdominal cavuty, except the middle of its posterior face, are formed at their upper part, which is the most extensive, of several superimposed layers of muscles, most of which are broad and flat, called the abdominal muscles ; and it is in this direction also that its dimensions and form vary the most. Its lower portion, on the contrary, the pelvis, admits of the least motion, because it is principally composed of firmly articulated bones, viz. the sacrum, a fusion of broad vertebræ, and the coxal bones, which unite with it backward, and with each other forward. The pelvis is also the narrowest visceral cavity of the trunk, and the narrower and more manifold connections of the organs it contains with its parietes, cause it in some measure to resemble the neck.

The parietes of the thoracic cavity, except the lower, which separates it from the abdominal cavity, and is formed by a broad muscle, the diaphragm, are composed of the ribs, which are movable, lateral prolongations of that portion of the spine which makes its base, of the sternum, which corresponds to the vertebral column forward, and of the muscles situated upon, under, and between the ribs. Hence itaparietes, though movable, are not susceptible of such great changes in their dimensions as the abdominal parietes ; its form is more constant, and normally depends upon these parietes, while that of the abdomen depends upon the parts contained in its cavity.

Finally, the neck is the narrowest and shortest portion of the trunk. The latter enlarges gradually from the neck to the lower part of the chest and the upper portion of the abdomen ; but after leaving this point, it gradually contracts to its extremity, and terminates by a very narrow opening, which is susceptible of enlarging, from the mobility of the bones attached to the extremities of the vertebral column.

§ 463. The outer surface of the divisions of the trunk which we have mentioned is itself divided into several regions. In this respect we may imagine the abdomen divided into three parts, situated above each other, by two transverse lines which partially or wholly encircle it.

Of these two lines, the upper passes over the lower ribs, and the lower over the summit of the coxal bones. We have now three compartments : the first above the upper line, the second between this and the lower, and the third below the lower line : these also are divided into several regions by almost perpendicular lines.

The upper is called the epigastric region {regio epigastrica'). It does not include the entire circumference of the body, but only its anterior and its lateral faces. Its form is triangular, and it is composed of four other regions, two lateral and two middle regions. The right and left lateral regions are called the hypocondriac regions {R. hypocondriaeœ, hypocondria). They are bounded above by the anterior edge of the cartilages of the five false ribs, below by the upper transverse line, and within by the upper part of the two anterior perpendicular lines.

The two middle regions are situated one above the other. The inferior, which is the most extensive, is called the epigastrium {R. gastrica, s. epigastrica stricte sic dicta) ; the smaller, situated below the inferior extremity of the sternum, the cardiac or the prÅ“cordial region {scrobicvlus cordis, s. regio cardiaca).

The middle region is termed the mesogastric, or the ximhilical (R. umbilicalis, s. mesogastricu). It surrounds the centre of the whole abdomen, like a girdle, and is divided by perpendicular lines into five other regions placed at the side of «ach other.

The umbilical region {R. umbilicalis) forms the centre, and is so called because the umbilicus is in it. Those next to it, which comprise the external part of the anterior face and the anterior part of the lateral faces, are the iliac regions {R. iliaeœ). Finally, the posterior parts, which run into each other in the centre of the posterior wall, are called the lumbar regions (R. lumbar es).

The inferior region is termed the hypogastric region {R.hypogastrica). It comprises the upper but only the anterior part of the abdomen, and is formed of three other regions, the central, the proper hypogastric region {R. hypogastrica stricte sic dicta), extending from the upper boundary of this region to the pubis, to the anterior edge of the pelvis ; and the two lateral, the inguinal regions {R. inguinales), which are situated between the preceding and the iliac bones.

At the lower part of the abdomen, or at the pelvis, we distinguish, forward, the pubic region {R. pubis), which includes the external or' gans of generation, and is continuous below with the mons veneris ; backward and downward, below the pubes, between them, the anus and the thighs, the perinceum (perinÅ“um s. interfeminæum) ; and finally, backward, the nates.

§ 464. The chest is divided forward, on the sides and upward, into three mammary regions {R. mamiUares), backward, into the scapular regions {R. scapulares). In the neck also we distinguish forward and downward, the throat {jugulum) ; backward, the nape {cervix s. nucha).

§ 465. The head, the bulging upper extremity of the trunk, is generally round. It cannot in most of its extent change its form, because its foundation is a bony case, all the parts of which, except the lower maxiUary bone, are immovably articulated. It is divided very naturally into two parts, the skull {cranium), and the face {facies), the former composed of the brain, the walls of the cavity which contain it, and of the organ of hearing ; the latter, of the organ of sight, of smell, of taste, and of mastication.

The skidl occupies the upper and posterior part of the head and is round. The /ace is situated downward and forward, and is inregularly quadrilateral. The skull is always much larger than the face.

We distinguish in the skull, a lower part or base {basis), two lateral faces, an anterior or temporal region {R. temporalis, tempora), and a posterior or auricular regio7i {R. auricularis), an anterior face, comprising an anterior region, the forehead {R. frontalis), of which the middle and lower part is termed the glabella, and the upper region is called the sincipital or sinciput {R. sincipitalis s. sinciput) ; finally, an upper face, the top of the head and of the whole body, called the vei-tex, and a posterior or occipital region, called the occiput {R. occipitalis s. occiput).

The face comprises the region of the nose {R. nasalis), that of the moidh {R. oralis), and the region of the dim {mentum), which are placed above each other on the median line, and also two other lateral regions, of which the upper, called the cheeks {gcnce, regio jugalis), comprises almost all the breadth of the face, and the projection caused by the malar bones, while the lower, placed at the two sides of the mouth, and called the buccal region {R. buccalis), forms the parietes of the buccal cavity {cavum oris).

The three great cavities of the body, the cavity of the skull, of the chest, and of the abdomen, are also known by the common name of splanchnic cavities {cava, s. ventres). In each is situated one or several of the organs necessary to the preservation of the individual or of the species. The abdomen contains the most essential parts of the digestive apparatus ; and the genital organs are situated within it and in the lower part of its circumference, the pelvis. The heart, and the organs of resphation are placed in -the chest ; the vocal apparatus in the neck ; and the brain, and the most noble organs of sense in the head.

§ 466. The members, limbs [membra) are distinguished into the upper and the lower, or the pectoral, the thoracic, the abdominal, and the pelvic. They are long, composed of several sections -which move upon, and are placed after each other in the trunk, and are articulated so as to perform motions as a whole or as different parts. They are formed essentially of boneswhich occupy their centre ; of musclesand of tendons, which cover the different bones and direct their motions ; of fibrous and of synovial ligaments which unite the bones together ; of nerves ; of vessels ; of the skin which covers all these parts, and of cellular tissue which unites them as a whole, and at the same time separates them from each other. The parts composing the limbs become smaller and more feeble, as the distance from the trunk increases ; but all the systems which compose them unite in the same proportion, so that their motions also are more extensive. Farther, the upper and the lower limbs correspond perfectly, not only in the number and the volume of their dimensions, but in the general arrangement of their different systems.

The parts of the upper limbs, after leaving the trunk, are,

1st. The shoulder, the under part of which is indented, and is termed the arm-pit {fovea axillaris).

2d. Of the arm {brachium).

3d. Of the elbow {cubitus), the union of the arm with the next portion.

4th. Of the /ore-arm {antibrachium).

5th. Of the hand {manus).

The hand is divided into three parts, the upper, the shortest, which is called the wrist {carpus), the middle, the metacarpus, and the anterior, which is the longest -and is composed of the fingers {digiti). Each finger comprises three divisions, termed phalanges ; the thumb {pollex), however, has only two.

We distinguish in the arm four faces, the external {regio s. facies externa, s. extensoria'), the internal {regio s. facies interna, s. Jlexoria), the anterior {regio s. facies anterior, s. abiluctoria), and the posterior {regio B. facies posterior, s. adductoria) ; in the fore-arm, only two, the external, and the internal ; four in the hand, the anterior or the radial {mar go anterior, s. radialis), the posterior or idnar {m.argo posterior, s. cubUalis), the external or the upper, called also the back of the hand {facies externa, s. superior, s. dorsum), and the internal or inferior, called the palm of the hand {facies interna, s. inferior, s. vola).

The following are the divisions of the lower limbs :

1st. The thigh {femur).

2d. The knee {genu), the articulation of the thigh with the leg, the under part being called the ham {poples, s. fossa genu).

3d. The leg {crus), its upper and posterior fleshy part, being called the calf {sura) .

4th. The foot (pes), which is sub-divided into the tarsus, the metatarsus, and the toes {digiti pedis) ; these last are composed of phalanges arranged in the same manner as those of the fingers.

The inferior limbs are. characterized by firmness and strength, and the superior by suppleness and mobility ; the former serve to move and support the body, the latter to grasp external objects. The pelvic are usually much larger than the pectoral limbs ; some of their parts, however, as the toes, are less developed and smaller than the fingers.

§ 467. The configuration of the body presents remarkable differences at different periods of hfe, in respect to the forms and sizes of its component parts.(l)

At first, the anterior and the posterior faces of the body are divided longitudinally on the median line.

In a full grown man, the length of the head is one seventh of that of the whole body, measured from the vertex to the toes, and the space between the extended arms almost equals this length.

At first, the head cannot be distinguished from the rest of the body; hence, it increases very much in size afterwards. The neck is not separate from the trunk. We see no trace of the limbs. These do not appear till the sixteenth week, and then as small stumps, the superior being larger than the inferior. In the adult, the pelvic members are some inches longer than the thoracic ; but in the fetus, the pectoral are longer until the eighth month, so that the want of proportion gradually diminishes. Until the age of five years, the four limbs have nearly the same length ; but at this period, the inferior gradually lengthen, so that when fully developed, they are as long as the trunk and the head together.

In the early periods of existence, all the lower half of the body, in proportion to the upper, is generally much smaller than in the adult.

The abdomen projects considerably, not only from the greater development of the liver, but also because the smallness of the cavity of the pelvis does not allow the bladder and the internal organs of generation of the female to descend into the cavnty of the pelvis.

The lumbar portion however is then much longer in proportion than in the adult, owing, no doubt, to the great size of the liver, as also to the slight development of the respiratory organs, and of the cavity of -the chest, which is not onty lower, but flatter.

The principal sexual differences are, (2) besides those already mentioned, -the considerable size of the skull in relation to the face, and of the head in proportion to the rest of the body, the smaller size of the thoracic cavdty, the greater uniform breadth of every part of the abdominal cavity in the female, while it is naiTower upward, and broader downward, in man ; the greater length, and finally, the capacity of the pelvis, which is much greater in every respect, in the female.

(1) Sue, Sur les proportions du squelette de L'homme, examiné depuis l'âge le plus tendre jusqu'à celui de vingt-cinq, soixante, et au-delà, in the Mém. présentés de Paris, vol. ii. p. 572.

(2) Ackermann, De discrimine sexuum prœter genitalia, Mayence, 1788.

From this, it happens that when a man lies on his hack, the anterior face of his chest projects above tire symphisis pubis, which is not the case in the female.

§ 468. Such is the normal form of the human body ■ but it offers numerous anomalies, of which we shall briefly state those only which are primitive.

1st. Of ihe Anomalies in quantiiij.

A. Imperfect development. This anomaly is greatest when the upper part of the body is deficient to a greater or less extent, constituting acephalia.{\)

This monstrosity can exist in an infinite number of degrees, from the existence of only one inferior limb to a slight defect in the formation of the bones of the skull, by which its cavity is imperfectly closed. It is divided into true and false acephalia {A. vera et spuria) ; the latter, however, should be called simply acrania, anencephalia. Sometimes more than the head is deficient in true acephalia. The reverse of the imperfect development of the skull is that of the face, distinguished principally by the union of the two eyes or of the two cavities of the nose, the smallness or absence of the lower jaw.

The reverse of the imperfect development of the upper part of the body is that of the lower part, consisting essentially in the union of the two legs into one, placed on the median line, at the same time being bent, so that its anterior face becomes posterior, and the posterior, anterior.

Here we may remark generally, that the imperfect development of the lower portion of the body never exists to so great a degree as that of the uiiper part, which is probably owing to the laws of formation ; for in birds, at least, the trunk seems to be formed from below, upward.

The imperfect development of the anterior and posterior faces of the body is shown by the want of union between the two lateral halves, and by the imperfect formation of the cavitieé' fissures ; in the head, by the fissure of the skull in false acephalia, and by the different degrees of the want of union between the two portions of the palate ; in the trunk, by the spina bifida posteriorly, and anteriorly by fissures of the chest and abdomen, through which the different viscera protrude. These fissures arise by the part remaining stationary at some of the degrees through which it passes. We are not however authorized by any phenomenon to admit with Tiedemann, (2) that they are caused by a want of development in those vessels which in the normal state unite on the median line. It is much more correct to consider the deviations of formation of all the parts situated near the fissure as the common effects of one and the same cause. We pass over the fissures in some particular organs which coincide with these monstrosities.

(1) Mappus. De acephalis. — Meckel, Beyträge zur vergleichenden Anatomie, 1808, vol. i. part il. — Id., Pathologische Anatomie, 1812, vol. i. ch. iii. and iv. — Tiedemann, Anatomie der kopflosen Alissgehurtcn, Landshut, 1814. — P. Hostecks, Diss. de monstrositatum origine, Berlin, 1819. — P. Feiler, ücber angcbornc menschliche Missbildungen, Leipsick, 1820. — GeoITry St. Hilaire, Philosophie anatomique ; monstruosités humaines, Paris, 1823. — Serres, Essai d'une théorie anatomique dés monstruosités animales; in the Bulletin de la soc. méd. d'Em., September, 1821. — Dugès, Considérations sur les causes et les différences des monstruosités du crâne et du rachis chez le fÅ“tus ; in the Revue médicale, vol. x. p. 353.

(2) Anatomie der kopflosen Missgeburten, p. 105.

The imperfect development of the hmbs, which presents so many degrees, expresses that of the two sides of the body. Sometimes all the limbs are totally wanting, and again, one only is deficient, either in whole or in part ; they often present only some defect in their development.

§ 469. B. The abnormal redundance in the number of the organs is the reverse of their imperfect development. This deviation of formation presents numerous varieties. They relate principally to the manner in which the supernumerary parts unite with the others ; this permits the abnormal redundance to be divided into common and generic. In the former, the redundant organs are united to the others in the same manner as the latter are jomed together. In the latter, they are united the same as the fetus is' with the organism of the mother.

The principal ciixumstances of the common redundance are ;

1st. The degree varies both in the number and development of the parts.

a. The redundant parts rarely, perhaps never, are more than double, so that it may also be called doubling.

ß. This doubling extends to some small part of the body more frequently than to a greater extent; for the smaller organs are double more frequently than those which are larger. The fingers are redundant more frequently than an entire limb, a trunk, or a head.

7. The supernumerary part is often below the standard, in regard to the size and number of the parts which compose it. The supernumerary fingers are often only fleshy appendages ; their bones, simply the excresences of a normal bone, &c. The redundancy, however, extends to an entire region more frequently than to a single system. If the number of vertebræ be increased by one, we find the same increase in the nerves, the vessels, and the muscular slips of the same region.

2d. The external parts alone are double much more frequently than the internal, or the central parts present this anomaly, no similar one being presented externally. Hence, we find supernumerary fingers {digiti) more frequently than abnormal vertebræ ; the former exist often, even without any increase in the number of the corresponding parts of the metatarsus, the metacarpus, the tarsus, and the carpus, while the contrary never occurs. So likewise 'vve not unfrequently find more than two mammæ, while a redundancy of the viscera is very extraordinary.

3d. Those parts which in the normal state are numerous are abnormal much more frequently thdn those which are single, or at most double. Hence we find supernumerary fingers, toes, or teeth, much more frequently than other parts.

4th. The most complex parts are doubled less frequently than those of simpler structure.

5th. A multiplication in one part is usually attended with a diminution in number or in development in another part.

6th. The multiplication of the whole body takes place, 1st, in the dimension of thickness, forward or backward ; 2d, in the dimension of length, upward or downward ; 3d, in the dimension of breadth, on the right or left side.

§ 470, a. Jllterations in regard lo quality. This section comprises two classes of anomalies, those in regard to the form or to the situation^ or tobotlrat the same time.

a. Anomalies in form are seen in the division of parts naturally simple^ or in the union -of parts generally separated. The vascular system, the osseous system, and the spleen, furnish us with examples of the first, the same two systems and the kidneys present instances of the second.

ß. Anomalies in situation alone are rarely primitive, in the strictest sense, although often met with as resulting from retarded development. W e however find sometimes a greater or less portion of the intestinal canal in the chest, the kidneys situated lower than usual, the heart too low, and sometimes, though very rarely, even in the abdomen.

y. The inversion of parts ought to be considered as the union of anomalies in situation and form, since we not only find in the left side parts which should be in the right, and vice versa, but they are also formed of a directly opposite type. This lateral inversion ahso presents very different degrees. Tlie inversion from before backward resembles that from one side to the other ; it takes place in the 'greatest degree, when the upper half of the body is turned forward and the lower backw'ard. Inversion from before backward is also seen in the surface of the body ; the other is not apparent externally, as it affects only the asymmetrical organs.

b. The second species of anomaly relative to the quality or hermaphrodism, is seen in the general form, independently of the genital organs, either when the body externally is of a character contrary to that of the sex {viragines et mares effemmati), or when a part of the body is formed in the type of the male, and the other in that of the female.

PART II. OF THE TOPOGRAPHY OF THE ORGANIC SYSTEMS

BOOK I. OF OSTEOLOGY

§ 471. The topography of the osseous system{l) should precede that of all the other organic systems, since the situation, the direction, and

(1) Besides the books already mentioned, those most in repute upon osteology are,

A. DESCRIPTIVE.

Hippocrates, De articulis liber, in Opp. omn., Venice, 1526. — A. C. Celsus, De re medicâ liber octavus, editio nova curante Fouquier et Ralier, Paris, 1823, 8vo. — Galen, De ossibus, Lyons, 1535. — J. Sylvius, In Galenum de ossibus commentarii, Paris, 1561. — Fallopius, Expositio inlibrum Galeni de Ossibus, Venice, 1571. — Eustachius, Ossium examen, in Opuscul. anat., 1726. — P. Paaw, PrimiticB anatomiæ de humant corporis ossibus, Leyden, 1615. — Riolan, Ostcologia ex veterum et recentiorum prceceptis descripta, Paris, 1614, in 8vo. — Leclerc, Osteologie exacte et complète, Paris, 1706, in 8vo. — B. S. Albiuus, De ossibus corporis humani, Leyden, 1746. — Boehmer, Institutiones osteologicœ.. Halle, 1751. — Tarin, Ostéographie, or Description des os de l'adulte, du fœtus, &c., Paris, 1753. — B. S. Albinus, De sceleto humano, Leyden, 1762. — J. T. Walter, Abhandlung von trocknen Knochen des menschlichen Körpers, Berlin, 1763. — Lecat, Cours abrégé d'ostéologie, Rouen, 1763. — Knackstedt, Osteologie oder Beschreibung der Knochen des menschlichen Körpers, Brunswick, 1781. — C. T. Hoffmann, Succincta descriptio ossium et musculorum, Nuremberg, 1783. — Sandifort, De~ scriptio ossium hominis, Leyden, 1785. — Berholdi, Initia doctrinœ de ossibus et ligamentis corporis humani, Nuremberg, 1794. — Sonnenburg, Compendium syndesmoosteologicum, Berlin, 1797, one of the most remarkable productions of medical literature.

B. PLATES.

B. S. Albinus, Tabulœ sceleti et musculorum, Leyden, 1747; 'Tabulce ossium humanorum, Leyden, 1753. — G. G. Muller, XXIV. Kupfertafeln, welche die Knochen das ganzen menschlichen Körpers vorstellen, Francfort, 1749.— Trew, Tabulœ osteologicœ, Nuremberg, 1767.— Innés, Eight anatomical tables of the human body, Edinburgh, 1776. — Loschge, Die Knochen des menschlichen Körpers und ihre vorzugl. Bander, Erlangen, 1789. — E. Mitchell, A ser tes of engravings respecting the bones of the human skeleton, Edinburgh, 1820.

C. DIFFERENCES IN REGARD TO SEX.

Ackermann, De discrimine sexuum prœter genitalia, Wurzbourg, 1788. — Scemmerring, Tabulœ sceleti femmini, Francfort, 1797.

D. DIFFERENCES IN REGARD TO RACES.

Sœmmering, lieber die hörperlichen Verschiedenheit des Europäers vom Neger, Francfort, 1785. Other descriptions and plates refer solely to the cranium, and will the forms of the latter, are fur the most part determined by those of this system.

§ 472. The numl^^f the bones in the normal state amounts to _^wo hundred and fifty-*, fifty-six of which belong to the trunk, sixtyÏÂl to the head, sixty-eight to the upper, and sixty-six to the lower extremities.

The bones of the trunk are,

, 1st. The twenty-four vertebra 2d. The sacrum.

3d. The four bones of the coccyx.

4th. The twenty-four };i6s.

5th. The three bones of the slernim.

The bones of the head are,

1st. The seven bones of the skull, viz. the spheno-occipital bone, the two temporal bones, the two parietal bones, the frontal bone, and the ethmoid bone.

2d. The four bones of the ear ; the malleus, the inciis, the stapes, and the os orhiculare.

3d. The fourteen bones of the face ; the two upper maxillary bones, the two malar bones, the two palate bones, the two nasal bones, the two lower turbinated bones, the two laclmjmal bones, the vomer, and the loiver maxillary bone.

4th. The thirty-two teeth.

5th. The five pieces of the hyoid bone, a central and four lateral pieces.

The bones of the upper extremities are,

1st. The two bones 'of the shoulder, the clavicle and the scapula.

2d. One to the ann, the humerus.

3d. Two to the fore-arm, the radius and the cubitus or ulna.

4th. Eight to the carpus, the scaphoid bone, the semi-lunar bone, the pyramiildl bone, and the pisiform bone, the trapezium, the trapezoides, the os magnum, and the unciform bone. i

5th. Five to the metacarpus.

6th. To the fingers, fourteen phalanges, two of which are for the thumb, and three for each of the fingers. Finally,

7th. Two sesamoid, bones.

The bones of the lower extremities are,

1st. One to the haunch, the coxed or iliac bone (os innominatum) .

2d. One to the thigh, the femur.

3d. Three to the leg, the tibia, iha filmla, and the rotula or patella.

4th. Seven to the tarsus, the aslragedus, the calcanéum, the scaphoides, the cuboides, and the three cuneiform bones.

5th. Five to the metatarsus.

be pointed out hereafter. Some also treat of the differences in the bones during' their development, and also of their diseases.

E. We have already mentioned the general â– works in the diseases of the bones. In ficseribing each bone \/e shall mention those in which details of their auon)alies may be found.

6th. To the toes, the fourteen phalanges, arranged as in the hand. Finally,

7th. Two sesamoid bones.

Most of these bones exist in pairs, that is, one'on each side. Thirtyeight are single and situated on the median line, but are, however, formed of a right and a left similar half ; we have as examples, all the bones of the vertebral column, the pieces pf the sternum, the middle piece of the hyoid bone, the vomer, the spheAp-occipital bone, the frontal bone, the ethmoid bone, and the lower maxillary bone. We shall leave the teeth, until we treat of the alimentary canal.

The order in which the bones are formed calls our attention, first, to the bones of the trunk, not only because this region is first developed, but because many of the other bones of the body, particularly those of the head, are formed in their type.

SECTION I. OF THE BONES OF THE TRUNK.

§ 473- The bones of the trunk may be divided into two classes ; the essential or the primitive bones, and the accessory or the secondary bones. The first comprise those formmg the vertebral column (columna vertebralis), the second, those situated opposite this column, and those which unite these to the spine.' T^e fifst comprehends the vertebrce, the os sacrum, the ossa coccygis ; t]je second, the sternum, and the ribs.

CHAPTER I. OF THE PRIMITIVE BONES OF THE TRUNK, OR OF THE VERTEBRAL column.

ARTICLE FIRST.

GENERAL REMARKS ON THE PRIMITIVE BONES.

§ 474. The vertebral column{l) occupies the centre of the posterior face of the trunk, and determines its length. When perfectly developed, it is composed of twenty-nine, rarely of thirty bones. The upper twenty-four bones are called the true vertebra {vertebra verce), the twenty-fifth is the sacrum, and the four lower bones belong to the cacti) For some remarks on the vertebræ considered in the whole animal series, and for the different osseus parts or ortranic elements which form tliem in their state of perfect development, and before all fusion caused by the rudimentary state of some one these elements, see the Considerations generales sur la vertebrae, by Geoffroy St. Hilaire, in the Mémoires du Muséum, vol. ix. p. 89.

cyx. The first twenty-four vertebrre are called irne vertebrae, to distinguish them from those pieces of bone composing the sacrum, which are, at first, so many vertebrae, but become fused into a single bone when the body is entirely developed, and hence are called/a/se vertebrae. All the bones which form the vertebral column are arranged one upon another, covering each other reciprocally and intimately united, so that the dimension in length is much greater than any other in the column they form ; each piece possesses but a slight degree of mobility, and this degree varies in the different regions. The vertebral column does not describe a perfectly straight line but a curve, for its superior or cervical portion (pars cervicalis) is convex forward, and concave backward, the dorsai, thoracic, or pectoral portion (pars dorsalis, s. thoracica, s. pecto7'alis) is concave forward, the lumbar or the abdominal portion {pars lumbaris, s. abdominalis) is convex forward, and concave backward and, finally, the sacral part {pars sacralis) is very concave forward, and convex backward. This curve is most marked in the sacral and in the lumbar regions.

I. GENERAL CHARACTER OP THE BONES OF THE VERTEBRAL COLUMN.

§ 475. All bones of the vertebral eolumn present certain general characters. If we include the pieces of the coccyx among them, we can make no general remark, except that they have a rounded form ; but when the coceyx is not included, we can assign to them characters much more precise. Tim njÿt gêr4eral condition of all the vertebræ is their annular form. Tlîis rh^, the' opening of which is always very considerable in proportion to the mass which forms it, gives support tO' several processes. The annularform is connected with one of the usesof the vertebral column, wdiich is to lodge the spinal marrow. The name of medtdlary foramen {foramen pro medulla spinali, foramen medtdlare) is applied to the hole in each of the vertebræ, and that of medidlary canal {canalis pro medulla spinali) to the channel resulting from the union of all the foramina of the vertebræ placed one upon the other.

The part of the vertebral column situated before the spinal marrow, is, exeept in one place, the strongest and thickest ; hence it is called the body of the vertebra {corpus vertebra.). It is always a little narrower on its anterior face and its two sides, so that its superior and its inferior faces project slightly beyond the lateral faces. The remainder of the lateral portion and all the posterior part of the vertebra is called the arch {arcus). The body is always straight and transverse, and the arch very convex. The processes on one hand contribute to a second use of the vertebral column, that of giving attachments to the muscles, which move it, the ribs and the skull, and also to strengthen the union of the vertelwæ. They may then be divided into articular ait^ musetdar processes {processus articulares el musculares), according to their principal uses, though all seem to fulfill these two functions '^t the same lime. The processes originate only from the arches of the vertebræ.

There are always seven processes. Four are articular, {processus articulares, condyloidei), these are also called the oblique processes (P. obliqui), and derive their name from the direction of their cartilaginous articular surfaces ; we find on each side a superior arrd an inferior, which arise from the lateral part of the arch. Of the other three which are muscular, two, one on the right, the other oir the left, arise transversely from the arch, between the superior arrd the inferior articular processes ; these are called the transverse processes (P. tran'sversi) from their direction.

The third is situated on the median line ; it arises from the middle of the posterior portion of the arch and proceeds backward. It has been called the spinous process (P. spinosus), as it is very long and pointed in many of the vertebræ.

In all the muscular processes we distinguish a base {basis), and a summit {apex).

Between the base or the anterior extremity of the arch of the vertebrae and the two articular processes of each side, the upper and the lower edge of the arch present grooves {incisura vertebralis) ; when the vertebrae are fitted to each other, these grooves form the holes of conjunction, or the intervertebral foramina {foramina intern ertebr alia ), , which communicate with the interior of the spinal canal, and through* which the spinal nerves emerge.

§ 476. All the vertebrae are united, in the main, in the same manner and at the same points. The upper and the lower faces of the bodies are firmly attached to each other in their whole extent, by the fibrocartilages which admit of but slight motion. The arches and spinous processes are united by fibrous ligaments, and the articular or oblique processes are connected together by capsules. ^

II. OF THEIR DEVELOPMENT.

§ 477. Besides these general characters presented by the vertebræ when perfectly formed, they resemble each other in the essential characters of their mode of development. In fact, they are always formed of at least three pieces ; a middle piece corresponding to the body, and two posterior and lateral pieces representing the two halves of the arch. Each probably arises by six or eight pieces, since we find a small nucleus of bone at the extremities of the spinous and of the transverse processes, and also on the upper and on the lower face of the body. We have observed this in the bodies of several individuals eighteen years old, and the facts mentioned by Ungebauer(l) accord with our own experience. Perhaps by examining the vertebræ in young subjects we shall ascertain that the body is formed by the union of the two lateral portions,(2) at least we have found this to be the case in

(1) Epistola osteologica de ossium trunci corporis hnmani sero assets visis earumdsmque genest, Leipsic, 1739.

(2) Bedard tlpnks differently, he adduces an arg'ument drawn from tlie anterior spina bifida, which very rarely, althoug'h sometimes, occurs, and in the neck only, because the fore part of the v'crtebral column developing' itself from the centre to the upper pieces of the coccyx, and several times even in the body of the first cervical vertebra, and also in the odontoid process of the second. The analogy of the sternum and of the spheno-occipital bone also leads us to believe that this is the case in all. Then the number of points of ossification is not three, as is generally asserted, but nine, or more properly speaking, eight. The lateral portions begin to appear at the third month ; the body shows itself later. The terminal points of ossification of which we spoke are not visible till long after birth ; for in the full-grown fetus the processes of the vertebræ .are not ossified. When the child is born, the different osseous points are still perfectly distinct.

III. OF THE SEXUAL DIFFERENCES.

§ 478. The bodies of the vertebræ are flatter, the transverse processes stronger and straighter in the male. In the female, these last are inclined a little backward so that the groove between them and the arch is deeper ; the spinal canal and the inter-vertebral foramen are also broader.

ARTICLE SECOND. OF THE DIFFERENCES BETWEEN THE TRUE AND THE FALSE VERTEBRAE.

§ 479. The characters hitherto mentioned apply both to the true and to the false vertebræ.

• The true vertebræ differ from the false vertebræ of the sacrum, as

they are not fused together when fully developed. We must however remark, that, after the age of fifty, we often find the true vertebræ united in one or many parts of the vertebral column.

The true arc also distinguished from the false vertebræ in their mode of ossification. In the normal state, the lateral portions unite on the median line, to form one piece before blending with the body ; in the sacrum, however, they are separated from one another long after they are united to the body.

wards the two extremities, while the posterior lateral parts are developed successively from above downward, thi.s separation oug-ht to occur backward and downward, which is most common, or forward and upward. He rejects also analogous proofs drawn from the anatomy of têtards, of birds, and of rabljits, as rcsting on erroneous observations. Having studied the commencement of ossification in the bodies of the vertebræ of the têtard and frog, he observed that it was a single point; the same occurs also in theothcr batracia, in the mammalia, and in birds. As to the cause of error, he thinks it arises from making observations upon subjects too young, and I'rom considering the peduncle of each apopliysis as the commencement of the body. On this sul.iject we must remark, that in those animals which have a horizontal position, the body of the vertebra being the least important part, is developed the last, by a relatively smaller point, while in man the reverse is true, especially in regard to the lumbar, tlie sacral, and the inferior dorsal vertebræ. See iS/ouveau Journal de médecine, vol. viii. 1820, p. 82. F. T.

ARTICLE THIRD. PARTICULARS OF THE TRUE VERTEBRÆ.

§ 480. The true vertebrae are divided into the cervical {vertebrœ cervicales), the thoracic, or the dorsal ( V. thoracicce, dorsales), and the lumbar ( V. lumbares) vertebrae, according to the region of the trunk which they occupy. We number seven cervical, twelve dorsal, and five lumbar vertebrae. They differ very much in their size and thickness, in their form, and the size of the spinal canal, and finally in the form and proportion of their parts.

§481. 1st. The vertebrae gradually increase very much in size from above downward, so that the cervical are the smallest, and the lumbar vertebræ the largest. The bodies particularly become broader, higher, and thicker. A lumbar vertebra is four times as massive as a cerrical vertebra.

§ 482. 2d. The spinal canal is smaller and rounder in the dorsal vertebræ, particularly in the central ; it is largest in the upper lumbar vertebræ. In fact, that of the first cervical vertebra is much larger than any of the others, but tins canal is not entirely filled with the spinal marrow. This opening is more obhque in the upper lumbar vertebræ ; in the lower lumbar, and in the cervical vertebræ, it has a triangular form, the summit of which is directed backward.

§ 483. 3d. «. The bodies of the different vertebræ differ from each other in several respects. In the cervical vertebræ, this part is not only smallest but it is very low in proirortion to their depth and breadth. The upper face is a Httle concave from before backward, and especially fi'om right to left, for the two lateral edges are very much raised above its level ; it also incbnes forward. The lower face is equally and even still more inclined in the same direction, but a little flattened towards its lateral edges.

The upper face of the upper dorsal vertebræ offers but slight traces of this arrangement of the body. In them, the upper and lower faces are perfectly straight, except in the centre, where they are a little depressed.

The bodies of the dorsal vertebræ become much thicker from before backward, and from above downward, less from one side to the other, so that the body of the middle is narrower than that of the upper dorsal vertebra, and of the lower cervical vertebra, but the' inferior are the largest in every sense.

The contraction of the body mentioned before is marked most strongly in the dorsal, and least in the cervical vertebræ.

The bodies of the dorsal vertebræ are particularly distinguished from those of all others by having small articidar surfaces situated on the sides, immediately before the union of these same bodies with the two portions of the posterior arches. We generally find an upperand a lower, on each side of the body the former being continuous with the upper edge, and the latter with the lower edge of the lateral face. Each of these facets is imperfect ; they do not become complete until they unite to the corresponding facet of the vertebra below, so as to form with it only one cavity, composed of the two i^ortions joined together at an obtuse angle, the upper being the smaller and the inferior the larger. In the last three vertebræ, we find on each side only one of these articulating surfaces. The tenth has only the usual upper semi-facet which unites with the inferior facet of the ninth. On the eleventh and twelfth, we see one only, which is straight and separated the upper edge. Hence why those of the superior ten dorsal vertebræ are called common lateral articular facets, and those of the last two, tl\Q proper lateral articular facets {facies articulares later-ales communes et proprice). They receive the heads of the ribs.

§ 484. b. The processes of the vertebræ differ considerably.

First, of the articular processes. The articular processes are less oblique in the cervical vertebræ ; their direction in the first two is almost horizontal. In the dorsal vertebræ, especially the lower, they are almost perpendicular ; the same is true also of the lumbar vertebræ. Their articular surfaces are arranged in the cervical vertebræ, so that the superior look upward and backward, the inferior downward and forward. In the dorsal vertebræ the superior are turned directly backward, the inferior directly forward. In the lumbar vertebræ the superior are directed inward, and the inferior outward. The last vertebra in this region is the only one which in some measmæ resembles the formation of the dorsal vertebræ in this respect.

The articular facets of the lumbar vertebræ are the strongest and highest, and those of the cervical vertebræ are the most feeble. The broadest are found in the first vertebra of the neck.

These surfaces also vary in form. They are straight in all the cervical and dorsal vertebræ, while in the lumbar vertebræ the superior are concave, and the inferior convex. Those of the first cervical vertebra are very deep.

In the cervical vertebræ, excepting the first, and in the upper dorsal vertebræ their greatest breadth is from one side to the other, and in the inferior dorsal and in the lumbar vertebra it is greatest from above downward. In the ffrst cervical vertebra, the superior are broader from before backward than from one- side to the other, while the inferior are round, as are also the superior of the second cervical vertebra, which correspond to them.

The form and proportions of the articular processes and of their surfaces admit then of ordy one movement m the lumbar region, viz. from above, downward ; while they have also a lateral motion in the regions of the back and the neck. At the lower part of the dorsal region, the motion from above downward is very limited by the height of the processes and by their greater perpendicular direction, and the lateral motion by the backward direction of the transverse processes which closely connect the joint. The vertebræ of the neck have the most motion, because, their surfaces being more horizontal, their articular processes are shorter.

§ 485. The transverse processes present no less remarkable differences.

The longest and strongest are those of the upper and middle dorsal and the superior lumbar vertebræ. Those of the cervical vertebrae are shorter, except those of the first, which are long. The smallest are those of the last two dorsal vertebræ.

Their direction varies. In the cervical vertebræ they are directed forward ; in the dorsal vertebræ, especially the inferior, backward ; and in the lumbar vertebræ they are more transverse, and mchne also a little backward.

They differ still more in their form. In this respect the cervical vertebræ are distinguished from the others, as their transverse processes are perforated from above downward, and a round canal is formed, which is sometimes divided by a transverse ridge of bone into an anterior and a posterior part, the latter being generally the smaller. This canal gives passage to the vertebral artery, and hence has been called the vertebral canal {foramen vertebrale). Hence why the transverse i^rocesses are considerably broader from before back\T'ard, and why their airterior and posterior edges, especially in the lower five cervical vertebræ, are more or less curved upward ; they form a groove in which the nerve from the spinal canal crosses the direction of the vertebral artery which passes before it.

Tliis groove is strongly marked in the sixth cervical vertebra. That part only of the transverse process which is situated behind the vertebral canal corresponds to the transverse processes of the other vertebræ. I'he anterior corresponds to the ribs ; however, the former is usually called the 'posterior root, and the latter the anterior root, of the transverse process.

The outer part of the vertebral foramen is sometimes imperfect. The first cervical vertebra is the only one in which the portion of the transverse process situated outside of this opening, and which is considerably broad from before backward, is at the same time very broad from without inward.

The transverse processes of the dorsal vertebrre are the most massive. They are not terminated externally by a point, as are those of the other vertebræ, but gradually swmll out, and their thickness equals or nearly equals their breadth. The iqrper ten are distinguished from the' others, as w'e perceive on the anterior face of their summits an articular surface {facies articularis transversalis) covered with cartilage, which unites to the tubercles of the ribs. This surface is concave in the upper vertebræ, but plane and often convex in the lower ; m the upper it is turned forward and upward, in the others its direction becomes more and more oblique outward and downward. Its extent also dimmishes as it approaches the loins.

The transverse processes of the lumbar vertebræ incfease in length fi'om the first to the third, and afterwards shorten from the latter to the fifth, SO that in this last they form only small thin- points. They are very much compressed from before backward, and consequently are much weaker than those of the dorsal vertebras. Their base usually projects at its posterior part into a small tubercle called the accessory process (processus accessorius), which is found in these vertebras only.

§ 486. The spinous processes of the cervical vertebrae are thinner upward than downward, and broader across than those of all the other vertebrae; their superior face is convex, and the inferior concave ; their posterior extremity terminates in two teeth, one on the right, the other on the left, which diverge, and are often bifurcated. They increase much in length from the first cervical vertebra, and are almost horizontal, although a little inclined doAvnward. We shall mention their differences in the first, second, and seventh cervical vertebrae when describing these vertebrae.

The spinous processes of the dorsal vertebrae are the longest of all : they lengthen especially from the first vertebra to the seventh ; at the same time they are -thicker and triangular. The upper ones are the broadest in proportion to their height ; but they gradually become thinner, so that at last their upper edge is sharp. Slightly contracted in the middle, they always swell out at their point, and terminate in a single small tubercle.

The spinous processes of the lumbar vertebræ are a little longer than those of the last three dorsal, and longer also than those of the cervical vertebræ. They are the highest and most compressed of all, so that in this respect they offer an arrangement contrary to that seen in the spinous processes of those of the neck. Their directiori differs from that of the others : it is not directly backward, or backward and downward, but is from behind forward, and from below upward.

ARTICLE FOURTH. OF THE SPECIAL CHARACTERS OF SOME OF THE TRUE VERTEBRÆ, VIZ. OF THE FIRST, THE SECOND, AND THE SEVENTH CERVICAL VERTEBRÆ.

§ 487. The first, second, and seventh cervical vertebræ present some peculiarities in their forms, and deserve a separate description.

A. NORMAL STATE.

I. Of the first cervical vertebra.

Although all the cervical vertebræ are characterized by a less difference between the body and the arch, this is much more marked in the first cervical vertebra than in the others. This vertebra is called the atlas. Its middle and anterior portion is broader across than in any other direction, as in all the vertebræ, but it is thinner from before backward than the arch itself, which almost equals it m height also. Hence this part is not called the body, but the anterior arch (arcws anterior) . This vertebra is distinguished from all others by the thinness of the superior and inferior edges of its anterior arch, while in the other vertebrae, except the second, the thickness from before backward exceeds the height. These two edges are destitute of cartilage. On the middle of the anterior face is a small tubercle {tuber ctdum anterius), to which a slightly concave and cartilaginous articular facet {sinus atlanlis, s. meclius) on the posterior face corresponds.

The posterior arch is more oblique than in all the other vertebrae. From its centre arises a tubercle {tuber-culum posterius) which frequently is almost imperceptible, but sometimes it also bifurcated, and goes horizontally backward.

The anterior parts of the posterior arch, which support the transverse and articular processes, are much stronger in proportion to the other parts of the atlas than in the other vertebrae ; hence they are termed the lateral masses {massÅ“ laterales). We have already mentioned the form and arrangement of the articular processes. Behind each process, and not, as in the other vertebrae, before each one or between it and the body, is a slight depression, forming the upper intervertebral groove {incisura intervertebralis superior, s. sinus lateralis, s. poste^'ior), which gives passage not only to the first spinal nerve, but also to the vertebral artery and vein. This groove is sometimes changed mto a canal by a ridge of bone which extends from the posterior extremity of the upper articular process to its posterior edge. Sometimes also another ridge of bone detaches itself from the posterior root of the transverse process, and extends to the posterior edge of the posterior arch, also forming a small canal. The upper articular surface is here directly continuous with the body, while in the other vertebrae it is separated from it by a gi'oove. In the centre of the internal face of the lateral masses, we observe a considerable depression and asperities which are seen only in the atlas.

The first cervical vertebra is the broadest of all, if we except the third lumbar vertebra. This circumstance is not to be ascribed, as in the other vertebrae, to the breadth of its body or to the length of its transverse processes, but to the great development of its articular surfaces, which depends upon its articulation with the occipital bone.

The first cervical vertebra differs from the others in its mode of articulation by the greater looseness in the parts which hold it. In fact the upper and lower edges of the posterior arch are not connected \yith the occipital foramen and with the body of the second vertebra by a fibrocartilage, but by much weaker fibres.

II. Of the second cervical vertebra.

§ 48S. The second cervical vertebra is distinguished from the others particularly by the height of its body, which is elevated considerably above its articular parts. This projection is called the odontoid

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I> E s C U 1 P T 1 V E A N A T û IM V ,

jM'occss {processus odontoïdes, s. dens). It is narrower than the body, and rounded. Above the base {basis) it becomes narrow ; this part is called the neck {collmn). Towards its extremity it bulges again into a small head {capihdum), and finally terminates in a blunt summit {apex).

The anterior face of the head presents a slightly convex, smooth, cartilaginous surface, which corresponds to the excavation on the anterior arch of the atlas. A similar one is seen on the posterior face. T'he odontoid process of the second cervical vertebra seenis to divide the body of the first cervical vertebra, to a certain extent, into an anterior and a posterior part, of which the former alone is ossified, while the other is the transverse ligament of Ihe first cervical vertebra. In tliis vertebra also the upper articular surface is uninterruptedly continuous with the body, and sometimes even there is no superior groove behind it, while the inferior groove is found as usual. The upper articular process is not situated above but directly before the lower ; so that it is supported on the body which is enlarged laterally, and its weight, consequently that also of the atlas and the cranium, bears upon the body, and not on the feeble and more movable lateral portions.

The anterior face of the body presents two lateral depressions, and above, a longitudinal ridge, which corresponds to the anterior tubercle of the atlas.

The second cervical vertebra is stronger, and its spinous process is longer than those of the other cervical vertebrae, except the last.

The atlas, which articulates with it by means of the odontoid process and the upper articular processes, and the head, which in fact is one with the atlas, rotate upon this vertebra, and turn around its odontoid process as a, round an axis. Hence it has been called the axis {episiropheus, axis).

The second cervical vertebra differs from all the others in regard to its connections, articulating not only with that which precedes and follows it, but also with the occipital bone, by its upper part ; and farther, the upper part of its odontoid process is not connected with the lower edge of the vertebra situated above it.

III. Of the sevcnili cervical vei tehia.

§489. The seventh cervical vertebra presents fewer peculiarities than the first two, and is particularly remarkable as uniting the characters of the cervical and thoracic vertebrae ; so that it would be more correct to call it one of the latter ; we shmild then have thirteen dorsal and six cervical vcrtebræ.(l) It resembles the cervical vertebræ only in the breadth and lowness of its body, and in the existence of the vertebral foramen. But the body of the first dorsal vertebra presents the same form, and the vertebral foramen here loses all its importance, since

(1) This remark issu just, that were it not in obedience to long usage, wc shouUi not admit seven ecrvical and twelve dorsal ^â– el tebra;.

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the vertebral artery never passes through it,(l) it is frequently tlefi' cient, and it sometimes exists in the dorsal vertebrae.

This vertebra resembles the dorsal in the great length of its transverse processes, which on each side suddenly increase at least four lines, while from the second to the sixth cervical vertebra they are of the same or of nearly the same length. It also resembles them in being throwh back, so that the medullary canal is farther backward than in the other vertebrae ; because it has on the lower part of the side of its body a small, lateral, articular semi-facet {facies articularis lateralis), which forms a complete surface by uniting to the upper semi-facet of of the first dorsal vertebra ; and finally because its spinous process suddenly exceeds those of the other cervical vertebræ very much, and, although broader than those of the dorsal vertebræ, is not bifurcated, and is thicker than those of the cervical vertebræ. It has been called i\i& prominent vertebra {vertebra jn'ominens), because the posterior part of its body projects beyond the other cervical vertebræ.

B. DEVELOPMENT.

§ 490. These three vertebræ differ also from the others in their mode of development.

The atlas is usually formed like the other vertebræ as respects the number of its points of ossification, but differs in regard to the time at which they appear. In the second and seventh cervical vertebræ the number of points of ossification is not the same.

In the other vertebræ the body exists long before the fetus is matured. In the atlas, on the contrary, we have rarely found it before the child is six months old. Of thirty skeletons of full-grown fetuses, and even of children, in one only have we seen a round nucleus of bone, two lines in diameter, in the cartilage of the anterior arch. Even at the age of two or three years, the two lateral masses are frequently united only by a band of cartilage containing one or more irregularly formed osseous nuclei, which are placed one at the side of the other. Some symmetry usually exists between the right and the left half of the body in this respect, so that although ossification often proceeds farther on one side than on the other, it never extends beyond the median line ; but in some few instances, even when the cartilage has entirely disappeared, we find the body formed of two very unequal parts, doubtless because of two or more osseous nuclei which are usually found on one side, the internal is united with that of the opposite side sooner than with the nucleus next to it on the same side. At the same time we sometimes perceive a round nucleus of considerable size between the posterior extremities of both sides. Tliis nucleus unites with the halves of the arch much earlier than the anterior, from which it is entirely separated, although b}^ a very thin layer of cartilage, long after the different parts of the other vertebræ are fused in a single piece.

(1) Soemmerring {Knochenlehre, p, 259) Iia.s mentioned tJiis, and we have frequently verified his remark.

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DESCRirTIVE ANATOMY,

We have never seen, what Bichat asserts is the most common arrangement, that the atlas is developed hy five points of ossification, one for the anterior arch, two for the posterior arch, and one for each of the lateral masses.

The second cervical vertebra is developed, leaving out of view its small processes, by at least five points of ossification, and not by four, as is generally said ; for the odontoid process is at first formed of two symmetrical osseous nuclei, which are usually visible at the end of the seventh and even in the middle of the eighth month of uterine existence; they are at first united and much smaller than the nucleus of the body, but exceed it in size in the full-grovm fetus, at which. period they have long been united. Besides these, two other nuclei probably exist which do not belong to all the other vertebrae ; we refer to a large, round, osseous germ, situated forward, between tlie nucleus of the body, and that of the odontoid process, and the anterior extremity of the lateral mass, and which is much narrower from before backward than the body. We have almost always found it iP children less than a year old, and even till the third year, allhougli lessened in size, and to be seen only on one side.(l)

The osseous germs seen first are those of the lateral masses ; next we observe that of the body, and then those of the odontoid process ; those which appear last are the intermediate germs, which are not developed till after birth.

The halves of the arch in the axis and the atlas unite later than in the other vertebræ, and among all the atlas is that in which they most frequently do not unite on the median line. In the second vertebra the two osseous germs of the odontoid process are first united, then the posterior extremities of the lateral masses fuse. The intermediate germs, which are the last developed, then unite with the borly and with the lateral masses ; the borly is fused with the latter ; finally the odontoid process unites also with them, so that the last trace of separation of the different osseous nuclei is a transverse furrow on the anterior face, between the body and the odontoid process.

The seventh cervical vertebra is developed by five points of ossifica^ tion. Besides the three which usually exist, the anterior circumference of the vertebral canal is already formed in great part in the fetus of seven months, by a separate oblong osseous nucleus, which extends from the lateral parts of the body to the posterior root of the transverse process. The anterior root is then developed separately, while in the other cervical vertebræ it is merely a prolongation, the anterior and internal extremity of the transverse apophysis turned outwardly. Our observations have satisfied us that this arrangement, which Hunauld(2) considers simply as a variety, ought to be regarded as the normal state, as Sue(3) and Nesbitt(4) think, although it is not mentioned in the trea (1) Nesbitt {Osteogenic, p. 66) mentions the.se osseous particles as existing' also in the fetus at birth ; but we have never seen them.

(2) Mem. (le I'ac. des sc., 174Ü. p. 537.

(3) Mem. prés, n I'ac. dc Paris, vol. ii. p. 572.

0) Osteogenic, p, 66.

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lises on osteology. The union does not take place till after the second year. This peculiarity also demonstrates that it would be more proper to regard the last cervical v^ertebra as the first dorsal ; for the small bone in question is evidently a rudiment of a rib, corresponding only to the neck of this rib, but representing it perfectly, and differs from the other ribs because it does not unite to the sternum by means of a cartilage, but fuses regularly with the vertebra to which it is united ;(1) but it often remains distinct during life, and elongates itself like a rib. (2) The seventh cervical vertebra approximates those of the neck and back still nearer than they have hitherto appeared, as the anterior root of their transverse process decidedly corresponds to a rib, although it has not been developed by a special point of ossification.

This transition from the cervical to the dorsal vertebræ would seem still more gradual if, as we think ourselves authorized to conclude from facts, the sixth cervical vertebra is also formed by the union of five osseous germs. In a child which died when nine months old, we found a small rounded nucleus of bone on each side, next to the body, in the part corresponding to the anterior and internal extremity of the anterior root. We have even seen traces of this bone in another child, two years old. This nucleus, however, is much smaller than in the seventh vertebra, and there is only a simple layer of cartilage extending from it to the outward extremity of the posterior root, before the vertebral foramen. Besides, judging from the last instance, it never unites just at the posterior root, but the internal extremity of the lateral part glides forward and outward between them.

The second, sixth, and seventh cervical vertebrae resemble each other then very much in their mode of development, so that we are authorized to consider this intermediate rounded nucleus of bone as the rudiment of a lib, although in truth it is very imperfect. We ought also to consider the small lateral germs in the body of the axis as allied to it. It is then somewhat remarkable that they are found exactly in the upper and lower cervical vertebræ ; in the latter, because the ribs arise from them ; in the former, because the articular portions of the occipital bone and the styloid processes of the temporal bone result from their development and enlargement.*

(1) This peculiarity of the seventh cervical vertebra is important in two respects : first, it establishes between the skeletons of the mammalia and of the other vertebrated animals a greater analogy than has hitherto been admitted ; for an analogy to the upper ribs of birds and reptiles had never been found in the mammalia. Secondly, it furnishes a new argument in support of the law that the formations which are transitory in the superior animals become permanent in those of the inferior classes.

(2) Meckel, Handbuch der pathologischen Anatomie, vol. ii. — Deutsches Archiv für die Physiologie, vol. i. part iv. fig. 6.

• Most anatomists distinguish also,

1st. The first dorsal vertebra. It presents an articular face above, and a semifacet below, on the sides of its body.

2d. The tenth dorsal vertebra. It frequently presents an articular face on both sides of its body.

3d. The eleventh dorsal vertebra. Its body is almost round, and presents an

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DESCRIPTIVE ANATOMY.

ARTICLE FIFTH.

OF THE FALSE VEKTEBRÆ.

1. OK THE SACRUM.

§ 491. The sacrum, or sacral bone {os sacrum, chmium, laktm), follows the last lumbar vertebiTi, whih which it is articulated m the same maimer as two vertebrae are miited. Although not the last bone of the vertebral column, it hoAvever supports it, bemg the broadest and the strongest.

Its form is irregularly quadrilateral, being larger and tliicker upward, but becomes nan'ower and thhmer downward. It resembles a large vertebra formed by the fusion of five placed over each other, and combines all the characters of the true vertebrae. The sacral canal {canalis saci-alis) extends from the upper to the lower extremitjq between a central and anterior portion, the body, and a tlfimier posterior portion, the arch ; this canal gradually contracts, especially from before backward. The upper face of the body is slightly concave, and covered •with fibro-cartilage ; the inferior, to which the first piece of the coccj'x is attached, is also covered Y^fith cartilage. On each side of the arch is detached a transverse process ; in the centre of the arch is a more or less mterrupted series of elevations, which represent the spinous processes of the vertebrae. Along this crest we observe on each side, on the posterior face of the arch, another series of small asperities, which correspond to the articular' processes. Fmally, between these and the body we find holes called sacral foramina {foramina sacralia), which correspond to the mteiwertebral foramina.

The differences between the sacrum and a common vertebra arise principally because it is composed of several vertebrae fused together, and because this fusion occurs at points too where there is no miion between the true vertebrae.

Hence we find no simple sphious processes, but spines sometimes separated and equal in number to the pieces of the sacrum, and sometimes aU or many of them fused together m a crest (cris/o).

The articular processes are fused, and mstead of them are tubercles sometimes hardlj'^ perceptible. The two upper and the two lower are very distinct, and are called the horns of the sacrum {cornua sacralia). We usually find, mstead of the broad, loose, and cartilaginous articular surfaces, only sharp and slight^ projecting edges ; sometimes

entire articular surface on each side ; its transverse processes are very short, and have no articulating- surface. "

4th. The twelfth resembles the eleventh ; hut its lower articular process is convex and looks outward.

5th. The fifth lumbar vertebra. Its body is flat, and the lower surface is oblique to articulate with the sacrum.

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however the inferior articular processes of the first false vertebra have also, like the other vertebrae, extensive and loose articular surfaces.

The foramina from which the last spinal nerves emerge appear double, so that we have an anterior and a posterior series of sacral foramina. But these foramina open into the spinal canal at the same place, and are double only because the transverse processes are united at their superior and inferior edges, outside of the holes through which the nerves pass.

These foramina are the anterior and the posterior openings of one connected canal, of which the upper are much larger than the lower, and diminish much from above downward.

The halves of the arches of the sacrum are united late ; so that the ring of the two lower false vertebrae not unfrequently remains imperfect during life.

The anterior face of the sacrum is niore or less concave, and the posterior more or less convex, according to the sex. The former is smoother than the latter ; it presents only four transverse ridges, placed each between two pairs of sacral foramina, and which are the traces of the primitive separation of the five vertebrae. We perceive also fourpairs of anterior sacral foramina. The posterior face presents five ranges of eminences ; one in the middle, which is unmated, formed by the spinous processes, and termed the crest of the sacrum {crista sacralis) ; near it, on each side, a second, which arises from the fusion of the articular processes ; finally, outward, a third, which marks the fusion of the transverse processes with each other. Between these two pairs of eminences we find the four postei-ior sacral foramina.

The lateral face of this bone is very broad and thick at its upper part. Its anterior part is smooth, covered with cartilage, and called the auricular surface {facies auricularis) ; the posterior part is very rough. The lower portion of this surface is so thin that it seems simply an edge.

§ 492. The sacrum is developed in the following manner. Long after the bodies of the true vertebrae are perceptible, we see, in the fourth month of pregnancy, the bodies, then the lateral massesof the false sacral vertebræ. The lateral masses are not all formed of the same number of osseous germs, for there are two on each side in the three upper pieces, while we find only one in the two inferior. Of these two nuclei, one, which forms one half of the arch, is found backward ; the other, forward : both unite with the body. The posterior faces of the lateral parts of each vertebra are developed long before the anterior parts, which form almost all the articular surfaces for the iliac bones. In this manner the twenty-one osseous germs which compose the sacrum iii the matured fetus are gradually formed. The first three false vertebræ contain five each ; the other two have three. All have a central and larger piece, the nucleus of the body. The two inferior have on each side only the half of an arch, composed in the first three of two osseous germs — an anterior, which is curved forward, and a posterior, which is curved backward. They continue separate till the

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age of three j^ears. However, the extremities of the two portions of the arches which are turned backward and toward one another are developed, as are those of the inferior vertebræ, which in the full-grown fetus are directed precisely from before backward. At the age of three years, the three pieces of the lower vertebræ begin to unite, and then the same occurs with the posterior and the anterior pieces of the lateral portions of the three upper pieces ; finally, these lateral parts also unite with the body. We not unfrequently find in subjects five years old the first vertebra composed of five pieces, and even at seven years of age we can trace this former separation.

The bodies and transverse â–  processes of the different vertebræ are joined together much later, and only when the growth is terminated ; the same remark applies to the posterior extremities of the halves of the arches.

§ 493. The sacrum, before its growth is perfected, is very analogous to the other vertebræ, inasmuch as its false vertebræ are not yet united. The latter resemble the proper vertebræ in regard to their mode of development, being composed of a body and of lateral parts. However, the number of these lateral parts in the upper vertebræ differs from what occurs in most of the vertebræ ; but among the cervical vertebræ we find some which arise also from the union of several pieces. A more important difference is that of the period at which these osseous pieces are developed and united. In fact, in the true vertebræ the lateral masses appear first, while in the false vertebræ the bodies are seen first. In the former, the posterior extremities of the lateral parts unite before the anterior are joined to the bodies ; in the latter, they are fused with the bodies long before they are united to one another.

§ 494. The sacrum is articulated, at its upper part, with the body of the last lumbar vertebra by means of a fibro-cartilage, and with its inferior articular processes by two capsular ligaments ; laterally, with the os ilium by a fibro-cartilaginous mass and several fibrous ligaments, and with the os ischium by fibrous ligaments. Finally, its lower extremity is articulated by ligaments and cartilage with the first piece of the coccyx.

§ 495. The sacrum is wedged in between the iliac bones, and forms the posterior wall of the pelvis. It properly sustains and supports the vertebral column and the head. It however projects backward very much, and forms, at its point of union with the last lumbar vertebra, a very prominent angle, called the jyromontory (promontormm) .

§ 496. The sacrum is one of those bones in which the differences of sex are very manifest, as it forms a constituent part of the pelvis ; these depend upon the difference in the functions of the male and female. In the female it is much broader and shorter and much less curved than in the male. The promontory also projects more than in the male.*

• Cloquet states that the dimensions of the sacrum in tlio female arc g'enerally

from 4 to 4à inches Ions' I its breadth at the upper part nearly equals its length ; at the lower part it is not more than 6 or 7 lines ; from the middle and projecting part

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OF THE COCCYX.

§ 497. The coccyx {ossa coccygis) is a collection of the smallest and most imperfect vertebrae. As the inferior false vertebrae of the sacrum do not form a complete ling, because the two portions of then arch do not unite, so those of the coccyx present no trace of the posterior arch ; and when we perceive at its posterior part two projections opposite to one another, which correspond to the lateral portions of the vertebrae, they are never long enough to touch.

§ 498. We usually find four bones of the coccyx, rarely five, and then alwaj^s in the female. These pieces are placed one above another, like the true vertebrae, and form a series of bones convex backward and concave forward.

The upper piece, and generally the first only, is much more perfectly developed than the others. We can always distinguish in the first, and sometimes also in the second, a middle piece, which is stronger, the body, and two lateral parts. The latter become two transverse processes, terminated by a blunt summit, turned a httle forward, curved very much from below upward, which are the rudiments of the transverse processes, and two posterior, which are those of the articular processes. These latter are shghtly inclined towards each other, but are not very distant from the posterior face of the body. They are always much elevated above the upper edge of the bone. Sometimes they are extended also beyond its base, but they never exceed its total height by the base, so as to produce a rudiment distinct from an inferior articrdar process. Sometimes we can see the superior horns and the transverse processes only in the second coccygeal bone ; the inferior horns are never seen, and the superior horns of the second are not arched towards each other.

The last two pieces of the coccyx are only round bones, the breadth of which is greater than the other two dimensions.

All these pieces rapidly diminish in size and development. In this respect they resemble the vertebrae of the sacrum, of wlrich they are a continuation, and with which the coccyx is often fused in the same manner as the false vertebrae of this bone are united, that is, by the body, the horns (articular processes), and the transverse processes, of which the last two are in general not directly imited, but are attached only by fibrous ligaments. Sometimes only some pieces of the coccyx are fused together, and the others remain separate and distinct.

§ 499. In the full-grown fetus, the first coccygeal bone generally contains at its centre a very small but distinct rounded nucleus of bone.(l) The others do not ossify till the seventh year. In a subject two years old, instead of all the osseous germs, we found the second piece formed of two separate lateral halves.

of its base to the fii'st tubercle of its posterior surface, its thickness is 2 and 2} inches.

(1) Albinus says that the whole coccyx remains cartilaginous till long after birth. This assertion however is not correct.

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ARTICLE SIXTH.

OF THE VERTEBRAL COLUMN IN THE ABNORMAL STATE.

§ 500. The anomalies of the bones of the vertebral column may affect, 1st, the separate bones, 2cl, all of them collectively.

These two kinds of anomalies may be primitive or consecutive.

I. OF THE PRIMITIVE ANOMALIES.

§ 501. Here we must remark generally, that of the different regions of the vertebral column, the fewest anomalies occur in the cervical vertebræ, at least as regards number ; this depends upon the circumstance that the cervical vertebræ are more constant in number in the mammalia, proving that the influence of the general law extends even to the anomalies.

§ 502. A. Anomalies in regard to quantity, a. Feebleness of formation. It is marked in various ways.

a. By the defect of entire vertebræ. Of this anomaly there are several degrees. When the upper half of the body is not completely developed (§ 468), the pectoral or the whole cervical region is sometimes deficient ; and when the skull is not perfectly developed, as in acephalia falsa (§ 468), one or more of the cervical vertebræ are frequently deficient. We have instances however of the absence of a vertebra when the formation is otherwise regular ; but this rarely occurs in the neck ; the regions in which it is most frequent are the lateral regions and that of the coccyx. Sometimes also only one half or the opposite halves of two vertebræ are deficient. We ought here to distinguish the real from the false or apparent defect ; in the latter case, it happens only that a vertebra of one region assumes the characters of those of another region. This occurs, for instance, when there is an excess or defect of a pair of ribs, when the last lumbar vertebra assumes the form and size of a sacral vertebra, when it unites with the latter on one or both of its two sides, &c.

ß. By the deficiency of some parts of the vertebræ. The most usual anomaly of this kind is a want of union between the right and the left halves, {spina bifida), which is observed by far the most frequently in the lumbar region, and exists in several degrees. The body itself is rarely divided into two parts. Generally the two halves of the arches are not united on the median line. This deviation of formation exists also in several degrees ; for sometimes one portion of the lateral half is deficient, while the remainder is turned outward ; sometimes there is simply a want of fusion between the two portions ; and sometimes they are separated only by a small opening. Although, when spina bifida exists in a great degree, and is attended with an imperfect development of the spinal marrow and with an accumulation of serum

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within the vertebral column, it is met with in the lumbar region more frequently than in any other ; yet when the osseous system alone is affected, the first cervical vertebra furnishes the most numerous instances of this anomaly, and this from the want of union in its two lateral halves. This deviation of formation is symmetrical, and is rarelj'- confined to one side of the body ; and then one semi-arch only is deficient.( 1 )

y. By the want of union behveen the posterior part and the body. This is the slightest degree of the anomaly.(2)

Ô. By excess. This includes the too great number of the vertebræ. One general law of this relation is that the superfluous vertebra is developed between and not at the side of the others. Here then the nature oTthe anomaly is determined by the rule itself. This anomaly, to which all our remarks of the contrary state apply, exists most frequently in the dorsal and in the lumbar regions. It is probable, however, that we cannot divide this into total and partial, and that when supernumerary vertebrae seem to exist, this anomaly is generally included in the class of anomalies in regard to quality.

§ 503. B. Of the anomalies in regard to quality. We may consider as such,

a. Jin unusual mode of development in the vertebræ. Sometimes certain parts of these bones arise from special nuclei. This is true, in certain cases, of the spinous processes ; we have already remarked it of the atlas (§ 487). Bichat also states that he has seen this anomaly, but does not refer to any particular vertebra. Probably we must attribute to it, at least sometimes, those cases in which the vertebræ are composed of an unusual number of pieces of bone, united either by a broad cartilage or by ligaments which permit them to play upon each other. Thus we have found the whole or a part of the spinous process(3) or of the transverse process(4) forming a distinct bone. The former is seen in the second cervical vertebra, and the second is met with more particularly in the lumbar region.

b. The abnotnnal change of one vertebra into another. This head includes, to a certain extent, the preceding anomaly, especially the appearance of the transverse processes as separate pieces of bone ; because it refers the formation of the vertebræ properly so called to the laws of the development of the sacrum (§ 492). This resemblance seems more just because all the examples of this anomaly found in authors have occurred in the lumbar vertebræ, where it has been seen, moreover, three times by Ungebauer and twice by Rosenmüller.

The vertebræ may also present characters differing in another manner from those which belong to them in their normal state. This head includes the enlargement and the increase in volume of the last lumbar

(1) Rosenmüller, De singul. et nativ, ossium corp. hum. varietatibus, Leipsic, 1804, p. 58.

(2) Rosenmüller, loc. cit.

(3) Kelch, Beiträge zur path. Anat., Berlin, 1813, p. 7.

(4) Unguebauer, loc. cit., p. 257.— Rosemntiller, loc. cii., p. 58.

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vertebra, and particularly of its transverse processes ; its firm articulation with the iliac bones ;(1) its fusion, with or without this change, with the sacrum ;(2) the fusion (which is sometimes original, and not produced by an external cause,) of the other vertebrae, for instance, of two dorsal, which assimilates them to the false vertebrae of thesacrirm ; the' change of the first piece of the sacrum into a true (viz. into a lumbar) vertebra, by the narrowness of the transverse processes, the want of fusion with the second, and its mobility upon the iliac bones ; finally, the change of true vertebrae into others, for instance, of the last cervical into a dorsal vertebra, by the absence of the vertebral foramen, the elongation of its transverse processes, and sometimes even the want of union between the anterior roots and the posterior roots o.f the transverse processes and the body. •

A general law in this respect is that the adjacent vertebrae are those which are most disposed to change into each other. Hence perhaps why the spina bifida is so often seen in the lumbar region ; for some analogy exists between this anomaly and the normal formation of the sacral vertebrae.

Another law, which is in fact less general, is that the corresponding vertebrae at the two extremities of the vertebral column tend the most to change into each other. This law is supported by the want of union between the two semi-arches, of which the first cervical vertebra furnishes so many instances, and the numerous cases w'here the body of this, of the second, and even of the third cervical vertebra is found formed of several pieces, of which the lateral correspond to the anterior germs of the transverse processes of the sacral vertebrae.

c. Various other deviations from the normal formation. Such, for instance, as the obliquity of the vertebrae, arising from the body being higher on one side than on the other. When this anomaly is not corrected by an inverse arrangement of the adjacent vertebræ, there results from it a greater or less obliquity of the vertebral column. This arrangement is usually the first degree of the partial defect of a vertebra ; for the side of the oblique vertebra which is least elevated is lower than usual, while the other side is not higher than usual.

II. OF THE ACCIDENTAL DEVIATIONS OF FORMATION.

§ 504. a. The most common of all the accidental deviations of formation, which are rarely congenital, is the curvature (curvatura) of the spine, of which we have three species, according as the column is curved backward {cypho.sis), forward (lordosis), or laterally (scoliosis). The first is the most common, the second the rarest. We may establish, as a general law, that a greater or less portion of the deformed vertebræ is destroyed on the concave side, that they are generally fused together on this side, and that the different kinds of curvature are most common

(1) Kelch, loc. cil., p. 7.

(2) Albiuus, Ann. acad., book iv. — Van Doeveren, Ohs. acad., p. 206, 7.

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in those parts where in its normal state the vertebral column is bent in the same direction (§ 475). This deformity necessaiily shortens the trunk in proportion to the loss of substance experienced by the vertebrae. We not unfrequently find cmves in several directions at the same time, especially in the first and second. The vertebral column also not uncommonly presents two curves, but in opposite directions, thus preventing in some measure the obliquity of the body, which is otherwise unavoidable.

b. The fusion of the vertebrae together, when not congenital and not dependent upon a curvature, rarely occurs, except in extreme old age. The bodies are very rarely fused, or united into one, by the ossification of the fibrous bgaments. Most usually they are connected to one another externally, on their anterior face, by means of a bony substance developed between them. We sometimes find the sacrum united with one and even with both of the ossa ilia.

c. Fractures ef the vertebrae are very rare, and require considerable force, because the vertebral column is composed of a great many bones articulated so as to move slightly upon each other. These fractures are almost always in a transverse direction.

d. From the same cause dislocations are very rare, unless they result from caries of the bones and the destruction of their ligaments. Hence why we often find dislocations of the vertebrae attended with union in a greater or less extent. F arther, these injuries are seldom seen, except in the most movable cervical vertebrae, and particularly in the fii'st.

CHAPTER II.

OF THE ACCESSORY BONES OF THE TRUNK, OR OF THE STERNUM AND THE RIBS.

I. OF THE STERNUM.

A. NORMAL STATE.

§ 505. The breast-hone {stermnn, ossa pectoris, xiphoides){l) is situated, like the vertebral column, on the median line of the body, directly under the skin, and opposite the spine. It forms the central anterior part of the chest, in the same manner as the spine forms its central posterior part. It may then Be justly regarded as an anterior vertebral column.(2) This anterior vertebral column when perfect is composed

(1) See an excellent memoir of G. F. St. Hilaire, on “ Le sternum considéré dans les quatre classes d'animaux rcrtébrês, et sur la détermination philosophique des pièces dont il se compose,” in Lis Philosophie anatomique, vol. i. p. 17, 1818.

(2) We bave collected in our Memoir on the analogy of animal forms many arg'uments drawn from comparative anatomy and from the history of the development of the fetus which favor this opinion (Bcylrage, vol. ii. part 2).

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of three pieces placed perpendicularly, and called, the first, the superior sternal bone, or the handle ; the next, the central^ or the body ; and the third, the inferior, or the xiphoid or ensiform appendage or process.

I

a, PERFECT STATE.

§ 506. This anterior vertebral column, or the breast-bone, is elongated, its length exceeding its breadth and also its thickness. Its upper end is much broader than its lower end. The bone does not grow narrower regularly, but becomes broader in the middle, after which it contracts again, and finally terminates in a point. Its anterior face is slightly rounded, and the posterior is also a little concave.

§ 507. The sternum is placed between the two clavicles and the seven pairs of ribs. The handle is the broadest and thickest part, the body the longest, and the xiphoid process the smallest in every dimension .

§ 508. The handle {inanubrimn) extends from the upper edge to where the cartilage of the second rib unites to the sternum. We remark, at the upper edge, on each side, a broad, oblong, cartilaginous cavity {cavitas clavicular is), where the sternal extremities of the clavicles are attached. Between these two cavities is. a much smaller semicircular fissure {incisura semilunaris). The lateral edges converge from above downward ; they are slightly concave and sharp in almost their whole extent, except at their upper and usually the thickest part, where they are broad, and hollowed out to receive the cartilage of the first rib. Hence each of the two edges is divided into a superior and an inferior fissure.

§ 509. The body {mucro, corpus) extends from the inferior extremity of the handle to the insertion of the cartilage of the seventh rib. Its form is the reverse of that of the handle, that is, it is narrower at its upper than at its lower extremity, and rounds off at its termination.

Its lateral edges usually present four semiciretdar grooves {incisurÅ“ semilunares laterales). At each of the places where these grooves are fitted to each other, we perceive a small cartilaginous articidar cavity {shuts articularis coslalis), which receives the cartilage of a rib. These grooves approach each other as we proceed downward ; hence the articular cavities approach also. The third, fourth, fifth, and sixth costal cartilages are united to the sides of the body alone ; the second articulates with it and with the handle ; the seventh is also attached to its lower edge, and slightly to the upper part of the xiphoid process ; the sixth and seventh are so near each other, that it is only in a very narrow and very elongated sternum that we can perceive a fifth and very small semicircular fissure between the articular cavities designed for them.

§ 510. The xiphoid appendage {processus xipho'ides) unites at its upper edge to the lower part of the body. It is usually loose, but is sometimes covered by the cartilages of the sixth and seventh libs, which rise before it to go to the body, in which case the last attaches

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itself to its anterior face. Its lateral edges are free in most of their extent. Its inferior extremity remains cartilaginous {cariilago xiphoides) until the most advanced age ; it terminates by a summit which is sometimes single, sometimes divided into two generally asymmetrical points.

b. DEVELOPMENT.

§ 511. The three pieces of the sternum (1), the handle, the body, and the xiphoid process, {ire usually separate at puberty. We have observed the xiphoid process united with the body more frequently than the body with the handle. Sometimes however, especially in old subjects, we find the three pieces fused into one bone.

The development of these bones varies much. As the trunk does not close anteriorly till very late, so the sternal bones do not appear early. From the fifth to the sixth month of pregnancy, we cannot perceive any points of bone in their broad cartilages. At this period the first germ shows itself usually in the handle, while the other two pieces present as yet no traces of ossification.

This nucleus of bone is generally single, oblong, and rounded ; sometimes however we find two, almost always situated one above the other, the superior being much larger than the inferior. When the single nucleus is not oblong and rounded in the full-grown fetus or after birth, but has the form of the figure 8, we have reason to think that there were two primitive nuclei, one above the other. It is much more rare to find two lateral germs arranged in such a manner that sometimes one is larger than the other, which then seems to be only an auxiliary piece, or they are both equal in size, and are perfectly symmetrical.(2)

It is less unfrequent to find more than two osseous nuclei in the handle. Albinus has seen three in one subject situated one above another, the lowest of which was very small ;(3) he also found in another individual four, one superior, occupying the breadth of the handle, and three inferior, a middle and two lateral.(4)

As the osseous nuclei of the handle appear before those of the other parts of the sternum, they are also of course much:, larger than the others when the other parts of the sternum have begunnöjc^sify. Of forty cases now before us, there is only one exception to thisSriSle/a fetus of eight months, in which the handle presents two nuelei'of bohej situated one above the other ; the superior is smaller than the inferior,

(1) Béclard has sometimes observed in the breast-bone of adults two pisiform

osseous points, placed one on each side, on the tracheal g-roove of the sternum. He calls them super-sternal or pre-sternal. See Nuuv. Journ. de mêd., vol. viii. 1820, P- 83. F. T.

(2) We know of but one instance of this arrangement, which is described and figured in our Beytrdge, vol. ii. part i. p. 145, plate 1, fig. 8.

(3) hoc. cit., p. 87.

(4) Loc. cit., p. 92.

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(which is another anomaly equally curious,) and both are not so large as the smallest of the three osseous germs.

After the seventh month we begin to perceive, in the body of the sternum, osseous nuclei which present several differences. In fact they vary much in number, size, and situation. They are developed at the side of each other more frequently than those of the handle, and almost symmetrically ; for of thirty-three sternal bones of fetuses and young children, we have found only nineteen in which the nuclei of bone were placed one above another. In eight of them the superior nuclei are single and unmated, and the inferior double, forming sometimes only one and sometimes several pairs. But in the other six, all the nuclei of the body are arranged in pairs, not however perfectly symmetrical in respect to size or situation ; the single are the most rounded, and the pairs are more elongated and smaller than those which are single, and hence each of them resembles only one half of a single one ; on this point our observations agree with those of Albinus.

The osseous nuclei, whether single or many, are always arranged so as to fall between two articular surfaces of the costal cartilages, whence it follows that one nucleus of bone is always developed between two ribs.

Usually, at least in all those cases we have now before us, when the osseous nuclei are situated over each other, we find only one between two costal cartilages. The observations of Albinus lead to the same result ; for this anatomist states that even when he has found several nuclei in an intercostal space, they were always placed one at the side of another. '

The superior nuclei are usually developed before the inferior ; hence they are larger than the latter, although subsequently the body of the sternum is broader at its inferior part.

We often find, in the fetus at birth, four osseous nuclei in the body of the sternum, viz. in the intervals of the second and third rib, of the third^a#?d the fourth, of the fourth and the fifth, and of the fifth and the sijftiî; but sometimes we find three only, and more rarely two. These differences arise from two causes : sometimes, but least commonly, the third and fourth osseous nuclei are fused into one which is larger ; sometimes, and this is much more frequent, the fourth and even the third do not exist. In the last two cases, particularly when the third osseous nucleus is also wanting, it often happens that those which exist are divided — a remarkable coincidence, as it shows but little energy in the formative act.

In the xiphoid appendage a single rounded osseous particle only is generally developed, and we rarely find two(l) which are not symmetrical. The nucleus first appears at the upper part of the appendage ; it gradually extends towards the base, but very seldom through the whole cartilage. Sometimes it is found even in the mature fetus, but, generally, it is not developed till after birth, sometimes even very

(1) Albinus, loc. cit. p. 80.

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late, not until the age of twelve, which is how'ever abnormal, as in most subjects it is found before the expiration of the first six months.

The fusion of the four osseous nuclei, or of the four pairs of nuclei, of which the body of the sternum is usually composed at birth, commences with those which are placed at the side of each other. We have observed, at least, in examining the skeletons of old persons in which there are two lateral nuclei of bone in the same interval, that all those found above each other are still separate. The first which are fused together are the inferior two, so that the seventh, sixth, and fifth costal cartilages are entirely, and the fourth is partly attached to to this piece of bone. The body is then formed of three pieces of about the same size, or of which, in old subjects, the inferior is much larger than the other two ; but the two upper primitive pieces are still entirely distinct from the lower, which is formed by the union of the third and fourth. The second unites with the last more late, while the first continues separated and is not fused till puberty, at which time the sternum is composed of only three bones, the handle, the body, and the xiphoid process, which are not usually joined together till at a very advanced period.

The sternum then gradually develops itself by osseous pieces, which, as long as they are not fused together, have the greatest analogy with the last false vertebrae, those of the coccyx, and which, like the latter, both in form and in their mode of articulation with the ribs, represent only the bodies of the vertebrae. It is easy, especially in the sternum of several animals, to demonstrate a cervical, dorsal, and lumbar portion ; and as the nuclei of its middle portion become a single piece long before puberty, as all the parts fuse together and form only a single bone, so, too, the false vertebrae of the sacrum always, and the true vertebrae frequently unite in a single bone, while on the other hand in all the mammalia, the osseous nuclei, or the vertebrae of the sternum, one of which is always found between two ribs, remain separate and distinct through life.

§ 512. The sternum in the female is generally proportionally longer and narrower than in the male. The handle also is often, but not always proportionally larger and broader in the female than in the male.

The sternum is articulated, in the points mentioned, with the cla\icles and with the cartilages of the seven upper ribs.

B. ABNORMAL STATE.

§ 513. The most abnormal state of the sternum is its entire absence, with or without a similar deficiency of thecommonintegumentsandof the ribs ; in the former case the heart is seen naked, in the latter it may be felt beneath the skin.(l) A modification of this state is the existence of openings which exist most generally at the lower part of the body of the bone, or in its xiphoid appendage, or the fissure of this appendage.

(1) Wiedemann, i'ebcr das fehlende Brustbein, Brunswick, 1791.

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DESCRrPTIVE ANATOMY.

It is remarkable that these openings are found only at the lower part of the body and in the xiphoid aj)pendage, — another argument in favor of the parallel between the vertebral column and the sternum, since spina bifida is seen more frequently in the lower part of the spine, the lumbar vertebræ, which corresponds to the lower portion of the sternum. The sternum is sometimes too short. This defect in formation is generally attended with the imperfect development of the chest. Then, generally, the bone is much broader than usual and more or less arched forward.

It is less common to find the sternum longer than usual, which is also curious, as furnishing another character of analogy between the anterior and the posterior vertebral column.

II. OF THE RIBS.

A. NORMAL STATE.

I. PERFECT STATE. a. General characters of the ribs.

§ 514. The ribs {costÅ“) are twelve pairs of thin bones ; their length exceeds their breadth ; they are slightly arched, convex outward, and concave inward, and are situated on the two sides of the chest, and form most of its bony parietes ; and they extend from the vertebral column to the sternum which they unite, allowing them to play on each other.

§ 515. All the ribs present the following general characters :

They all terminate backward in a round head (capitulum costÅ“), which is faced with cartilage. They are formed more or less perceptibly by the union of the segments of two different circles, that to which the posterior part belongs being much smaller than the anterior, and both of which run into each other very gradually. The ribs are broadest where these two circles meet, and their inferior edge often projects into a line, termed (he angle {cubitus). Their posterior extremity, which is of a rounded square form, is thicker, firmer, and narrower than the anterior, in which direction they become flatter, and evidently present two faces and two edges. The upper edge is usually slightly rounded, and the lower is sharp. In most of the ribs, the internal face, near the lower edge, and at the back part, becomes thinner and presents a groove, called the costal groove {stdeus costarum). Towards their anterior extremity, the ribs gradually become thinner and terminate by a slight,but not oval prominence. Most all of them present externally, behind the place where the posterior circle is confounded with the anterior, an elevation covered with cartilage and called the tubercle {tubercuhm costÅ“). The part between the head and the tubercle, which is usually contracted, is called the neck {cervix, collum) ; the rest of the bone, that is, its anterior portion, is called the body.

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The ribs are articulated by their heads, which are co\'ered with cartilage, with the lateral articular facets {facies articularis lateralis) (§ 483) of the bodies of the twelve dorsal vertebræ, and by their tubercles, with the transverse articular facets {facies articularis transversa) (§ 485) of -the transverse processes of these same vertebrae. At their anterior extremities, we find the costal cartilages {cartilago costœ).

The direction of the ribs is such that their posterior extremities are always higher than their anterior.

The situation of the ribs, and their relations with the dorsal vertebræ, prove, that they maybe regarded only as a greater development of the anterior roots of the transverse processes of these same vertebræ ; and their cartilages may be considered as imperfect ribs of the sternum.

b. Of the differences of the ribs.

§ 516. The ribs differ, 1st, in their size ; 2d, in their curve ; 3d, in their direction ; 4th, in their form, and in the relations of their constituent parts ; and, 5th, in their attachments.

1st. The ribs increase in size after leaving the two extremities of the chest. The first and the twelfth are the shortest. They increase from the twelfth to the seventh, and from the first to the sixth. The sixth and the seventh are about equal in length, and are longer than all the others.

But although the first and the twelfth are almost equal in in length, the mass of the latter is much less ; it is much thinner than the other. The twelfth rib is much shorter than the first ; besides, its size varies much more than that of the first.

2d. The curve diminishes considerably from the first to the twelfth ; the second, however, is usually more curved than the first. The inferior ribs are very flat ; the twelfth is sometimes straight. Whatever may be the case in respect to the proportional size of the curve, the first and the twelfth are similar in their curve as their composition by two segments of circles of different areas, is less evident than in the others. This arrangement is seen particularly in the last.

3d. The ribs descend much less from behind forward according as they are more superior. At the same time, the upper ribs have one of their faces turned upward, the other downward, one of their edges turned inward, the other outwai'd ; while, in the lower ribs, the edge which is internal in the others, is directed upward, and that which is external downward ; the upper face outward, and the lower face inward, so that the ribs seem turned on their axes.

The direction of the costal cartilages also varies. That of the first rib follows the direction of the bone, and descends obliquely to the sternum : that of the second, is perpendicular to it. All the others ascend, then: inclination upward increasing as we descend, except the last, the anterior extremity of which is unattached.

4th. The ribs differ in several respects in respect to their form.

a. The proportion of the neck to the body varies. The neck is proportionally longer as the rib is situated higher up, although its

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absolute length increases from the first to the eighth rib. The neck of the ninth rib is not generally much longer than that of the first, although the latter is very short ; that of the succeeding is still shorter. The last two which have no tubercle, have likewise no neck. At the same time, the tubercle projects the more the higher the rib is. As it enlarges, we most generally see developed two surfaces covered with cartilage, an interior and superior, and a posterior and inferior, which unite to form an angle ; and which, often, particularly in the upper ribs, with the exception of the first, are separated by a depression which has no cartilage. In the inferior ribs, this tubercle projects less, and has only a plane surface ; and in the last two ribs it is entirely deficient.

h. The grooves and angles {cubiti) formed at the union of the anterior and posterior segments are much more distinct and much longer from the third rib to the ninth, than in the others; and the length of the posterior segment, between the head and the angle, increases considerably from above downwards.

c. The first rib is the strongest, and especially the broadest, not only in proportion to its length, but positively. Its upper surface is more rough and uneven than any other.

5th. In respect to their attachments, the ribs vary in three different modes :

a. They differ in their manner of articulation with the dorsal vertebrae ; and here we have two different cases :

a. The ten, sometimes only the nine upper ribs, or even the first eight, are attached by their heads to a deep articular surface, forming a re-entering angle, and hollowed from the two nearest dorsal vertebrae. The others are received in a single round and convex articular surface of a single vertebra.

The form of the head also varies, having two surfaces united at a projecting angle in those ribs which are attached to two vertebrae, while in the others it has only a slightly convex surface.

ß. The ten upper ribs only are articulated by a tubercle, with the summitsof the transverse processes of the corresponding dorsal vertebrae. The last two are not arranged in this maimer, and their posterior extremities are not connected, except with the bodies of the vertebrae.

b. Neither are all the ribs united by their anterior extremities with the sternum, in the same manner.

Here, also, we have two different cases.

a. All the costal cartilages do not extend to the sternum. Those only of the upper seven ribs are attached to this bone, being fixed in its articular cavities (§ 509) by ligaments. The thin cartilages of the last five do not arrive at the sternum, but are only attached to the cartilage above. This is not, however, the case with all, as is seen in the twelfth, and sometimes the eleventh ; but their anterior extremities remain unattached, and they are connected with the other ribs only by the intercostal muscles, and by the broad abdominal muscles. On this is founded the distinction into true ribs {costce, verce) and the false

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ribs (costœ spuriœ). The upper seven are the true ribs, and the otherfive are the false ribs.

ß. The cartilages of the ribs have not the same length. Like the ribs, they increase in length from the first to the seventh, and then diminish from this to the last.

c. The ribs differ in respect to their connections with each other. While the superior six are not united, the cartilages of the sixth, seventh, eighth, ninth, and tenth are joined together. Of the last, the upper are usually united by the prolongations of the upper cartilage which correspond to the depressions in the upper edge of the cartilage below, and which are kept in place by capsular ligaments. This is not the case with the last, which are simply applied to one another.

§ 517. The differences between the ribs, principally the greater length of the neck, the angular form of the articular surface of the head and of the tubercle, the greater projection of the latter, the diminution in length, and increase in breadth of the costal cartilages, and, finally, their connections with the sternum, by its anterigr« extremity, demonstrate this important proposition — that the ribs are less movable the higher they are situated, and that their mobility diminishes very much from above downward.

n. MODE OP DEVELOPMENT.

§ 518. The ribs are among those bones which are formed and developed the first. From the beginning of the third month of fetal existence, their oseous portion is, proportionally speaking, as large as when fully developed. They arise, however, from three points of ossification ; for the head and tubercle have each a nucleus, v^hich begins to appear at the age of sixteen years, and is soon fused with the remainder of the bone. These nuclei do not exist in the two or three lower ribs.

III. SEXUAL DIFFERENCES.

§519. The ribs of the female are generally strai ghter than those of the male. The posterior segment unites sooner with the anterior ; its curve differs less from that of the last, and disappears sooner in the female ; hence the chest is narrower. . The ribs are usually thinner ; hence the edges are sharper. Sometimes, however, this is far from being true. Their length is nearly the same : but we are satisfied from numerous observations that, in general, the length of the two upper ribs is proportionally, and when the subject is short, absolutely greater in the female than in the male.

B. OF THE RIBS IN THE ABNORMAL STATE.

§ 520. The ribs present four different anomalies.

I. The primitive deviations of formation, which are very interesting, belong, almost all, to the class of anomalies in regard to quantity.

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§ 521. The deficiency in formation is seen :

a. In less than the usual number. As a general rule, we say, that there is seldom or never deficient more than one rib on each side ; that this is never the upper, but the last ; that one on each side is deficient, more commonly, than on one side only ; finally, that the absence of a rib is attended, or not, with the absence of a vertebra. Sometimes only a costal cartilage is deficient, and then two ribs are inserted in the same cartilage.

b. In their shortness. The lower ribs, particularly the twelfth, are those which are unusually short, either on one side or on both ; so that they seem only as small vertebral processes. Sometimes these bones have the usual length, but are very slightly arched, which establishes a resemblance with most of the mammalia, and generall_y, with most animals in which the cavity of the thorax is almost always narrower than in man. This deviation of formation is generally confined to some ribs. In some cases this anomaly extends to all, either on one side, or on both sides ; and- then, sometimes, the ribs do not reach the sternum ; and sometimes they are connected with this bone, as usual. When the latter case occurs, the cavity of the chest is very much contracted.

c. Bij imperfect ossification, whence the ribs are sometimes divided in a part of their length by a cartilage, as in birds ; or the costal cartilages are more or less deficient, so that the ribs are not connected with the sternum, as in the lowest reptiles and in the fishes. The least and the most common degree of this anomaly is that which consists in the shortness of the cartilage of the seventh rib ; by which arrangement the number of the false and of the true ribs is equal.

§ 522. The excess of the formative power is seen in a still different manner in the ribs.

a. The slightest degree is an abnormal length and height of the ribs, or of their cartilages, or of both, which is seen in some ribs only more generally than in all, and exists on one or on both sides. We not unfrequently find the anterior extremities of these bones much broader than usual, which gradually leads to an increase of their proper number. Their enlargement establishes an analogy betwmen man and many animals, especially the pachydermata and the myrmicophaga, among the mammalia, and the chelonia among the reptiles.

The prolongation of the cartilage of the eighth rib increases the number of the true ribs to eight, as in apes.

b. A greater degree of this anomaly is a division of the ribs which always commences at their anterior extremity ; we have never seen them divided into an internal and external piece, but always into a superior and an inferior process. This last arrangement may also be construed into a general rule, the more important as it seems to indicate that nature imitates the fundamental type even in her anomalies, as we have before shown when speaking of the vertebræ. The two processes rarely have the same length. When the deviation of formation exists in a slight degree, the ribs close before the fissure, so that only a small opening is seen. When existing in a greater degree,

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one of these two prolongations is united with the cartilage, and when more anomalous, both are connected with it. The cartilage of the rib then is sometimes single, and only broader than usual, and sometimes divided partially, or in its whole extent, on the side of its posterior extremity ; this last anomaly may also exist without a division of the ribs, which may be broader than usual. In this case, the cartilage is broader than usual, or an opening penetrates through it ; or it may be bifurcated at one or the other extremity, and finally it may be entirely double, and then its posterior part is unattached or united to a lib.

Anather result of an excess in the development of the ribs is the formation of processes at their posterior part, particularly near the tubercle. This anomaly may exist in several degrees. Sometimes the process does not extend to the adjoining rib ; sometimes the two ribs unite either by a single process of a certain length belonging to only one of them, or by the union of a process from two ribs ; sometimes even there is a distinct bone between the two prolongations. This arrangement not unfrequently causes the fusion of two or more ribs, which fusion takes place usually at their posterior part. The former case is similar to the formation of bii'ds and the latter to that of the chelonia. The upper costal cartilages are sometimes united in a similar manner by prolongations or unusual processes.

c. The redundance of the ribs, to which their division and increase in breadth gradually lead, differs in regard to the situation, the number, the size, and the attachments of the supernumerary ribs.

a. The supernumerary lib usually forms below the twelfth and not above the first, in v/hich case the number and the arrangement of the upper ribs and the cervical vertebræ are the same as usual, while there is one dorsal vertebra too many, or at least the inferior ribs are only a little more developed. This supernumerary rib is sometimes found above the first ; in this case, it generally arises from the anterior root of the transverse process of the seventh cervical vertebra, which is unusually developed and which is not united to the rest of the bone ; the first rib is then generally longer and thinner than usual.

The increase in the number of the lower ribs is similar to the formation of the mammalia, and that of the upper to what is soen in birds.

ß. Number. 1st. The number of the ribs may be increased on one side or on both.

2d. We may find one or more supernumerary ribs on one side or on both at the same time. We generally find a supernumerary rib on one side only, which, by a double fissure, apparently mcreases the whole number of ribs to fifteen ; but we find a supernumerary pair of ribs more commonly than one supernumerary rib.

y. The size of the supernumerary ribs varies much. They are generally very small, and appear only as imperfect rudiments. The first degree of this anomaly at the top of the chest, is the imusual prolongation and sharpness of the transverse process of the seventh cervical VoL. I. 52

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vertebra, below, at the bottom of the thorax, the existence of a moveable little bone in the transverse process of the first lumbar vertebra.

Ô. The mode of union also varies. The lower supernumerary rib unites no more than the twelfth with the cartilages of the ribs above it. The superior is also almost always free, as are the upper ribs of several buds and reptiles ; but when it is more developed, its anterior extremity unites to the body of the one next to it, the first properly speaking, and when still longer, it may extend to the cartilage of the first rib, or may have a proper cartilage, going dhectly to the upper bone of the sternum.

§ 523. 3d. The anomalies in regard to qualHy are,

a. A too shght curve, the straightness of the ribs without any shortening.

b. Being curved in such a manner that their convexity is turned inward and their concavity outward.

c. The insertion of the anterior or of the posterior extremity of one or more ribs above or below, before or behind the usual point. This arrangement sometimes exists on one side only, and sometimes on both sides at the same time, either in regard to one rib, or several ; but it is less important and less curious than the first two kinds of anomalies.

524. II. The accidental deviations of formation of the ribs, offer nothing peculiar. From their mobility and the difficulty of fixing them permanently, it often happens that false joints are formed in them by fractures.

SECTION II.

OP THE BONES OF THE HEAD.

A. NORMAL STATE.

§ 525. The series of true vertebrae, those which are movable upon each other, terminates below in the sacrum, which is composed of five false vertebrae fused together ; this column supports, at its upper part, the head, which is formed in a similar manner (§ 465). The cranium and face, which compose it, include numerous bones, which usually may be easily separated from each other at the period of puberty, although, with one exception, viz. the lower maxillary bone, they are articulated by sutures (§ 243) which admit of no motion. At this period, the skull is formed usually seven, rarely of eight bones. In the face we number fourteen bones.

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CHAPTER I.

OP THE SKULL.

A. DESCRIPTION OF THE INDIVIDUAE BONES.

§ 526. The bones of the skull, regarded from below upward and from behind forward, are the basilar bone [os basilare,) the temporal bones {ossa temporum), the parietal bones {ossa parietalia), the frontal bone {os frontis), and the ethmoid bone {os etkmoiedum) . Many of these are very similar to entire vertebrae, or to the parts of vertebrae. Most of them are flat altogether or in part (§ 234), concave internally, and convex externally. They unite and inclose a considerable cavity. One face presents elevations and depressions {fossae et eminentiœ, s. juga digitalia, cerebralia), similar to those produced by the finger in a soft mass, and which resemble the external surface of the brain. Most of them are developed by several points of ossification.

I. OF THE BASILAR BONE.

§ 527. The basilar bone {os basilare) was first described as a single bone by SÅ“mmerring. Its anterior portion corresponds to the sphenoid bone {os cunéiforme^ s. sphenoideum, s. alatiim, pterygoideum, multiforme, polymorphon), and its posterior portion to the occipital bone {os occipitis), which are generally described as separate bones, because they are separable from each other in the skulls of young subjects ; but as they are found fused together when the other bones of the body are perfectly developed, and as the different parts of which they are composed are then united and blended, SÅ“mmerring's opinion is more correct than that of those who preceded him.(l) The basilar bone may then be termed also the spheno-occipital bone {os spheno-occipilale).

§ 528. The basilar bone occupies the inferior, middle, and posterior part of the skull. It is so wedged in between the other bones of the skull, that it articulates with all. Although it should be considered as one bone, the best way of describing it is to distinguish it, as is generally done, into two portions, the anterior, or the sphenoid bone, and the posterior, or the occipital bone.

(1) Knochenlehre, p. 109. — Spix attributes this opinion to Mondini, and blames it (^Cephalogenesis, Munich, 1815, p. 16) ; but we think he is wrong- in both respects. Mondini, it is true, speaks {Anat., Marburg, 1540, p. 48, 57) of a basilar bone of the head ; but he expressly considers the occipital bone as a separate bone, and understands by the term basilar the sphenoid, the temporal, and the ethmoid bones; so that he counted only five bones in the skull. On the other hand, as the sphenoid and the occipital bones are always fused together, even before all the bones are perfectly developed, we cannot consider them as two distinct bones, at least in man, although they are always distinct in most animats, for then we could not regard the sphenoid bone as a sing'le bone with any more propriety.

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a. OF THE OCCIPITAL BONE.

§ 529. The occipital bone {pars s. os occipitalei) foims the lower and posteiior portion of the basilar bone, and appears in every respect as an enlarged vertebra. Like all the vertebræ, it presents a ring composed of a thicker anterior portion and a thinner posterior portion ; the latter however is much more developed, is absolutely and relatively broader and higher than in the other vertebræ, while the anterior is at least smaller than the bodies of the dorsal and lumbar vertebræ.

§ 530. We distinguish, in the occipital bone, the basilar portion {para s. processus basihi7'is), the condploid parts {partes condyloidex, s.jugu~ lares), and the squamous portion {pars squamea).

§ 531. The basilar portion corresponds to the bodies of the other vertebræ, and consequently should be called the bodij. It is the most anterior, the smallest and the narrowest portion of the bone. In form it is an irregular hexagon, broader backward and downward, and thinner forward and upward. The middle part of its posterior edge is jagged, and forms the anterior edge of the occipital foramen. The two posterior lateral edges are inclined from behind forward and from within outward, and are blended with the anterior edges of the condyloid portions. The two anterior lateral edges converge towards each other forward. Its transverse anterior face is covered with cartilage, and when the basilar bone is perfectly developed, it is fused with the centre of the sphenoidal portion.

The upper or posterior face of the body strongly inclines from before backward, which depends imrticularly on the considerable thickness' of the anterior portion. From one side to the other is a deep depression, called the fossa of the medulla oblongata {fossa medullÅ“ oblongatæ). The line of demarkation which separates it from the anterior lateral edge is generally marked by the furrow of the posterior petrous sinus {sulcus sinus qietrosi posterioris). The inferior or anterior face is straight in comparison with the preceding. When, however, the skull is in its natural situation, it ascends from behind forward. We remark there, on the median line, a projection from before backward, called the basilar crest, or spine {crista, s. spina basilaris, s. pharijngea) ; or the sides, two transverse symmetrical elevations ; and behind these, several depressions. At its most posterior portion, it assists a little in forming the anterior extremity of the occipital condyles.

§ 532. The squamous portion forms the posterior and lateral parts of the occipital bone. It is thin, flat, broad, and curved in its upper and posterior portion which is the most considerable ; and in its inferior and anterior part, which is the smallest, — uneven, thick, and irregular. The latter corresponds to the anterior part of the arch of the vertebrae, which supports the transverse and articular processes ; the former, to the posterior part of the same arch, in the middle of which is the spinous process directed backward. The second is the proper occipital portion of most anatomists ; the other embraces the condyloid,

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articular, or jugular parts {^partes condyloideœ, articulares, jugidares) of authors.

§ 533. The condyloid or articidar portions are narrower and thicker forward, and backward they are broader and thinner. Their faces and edges are very uneven. On the upper face, where it joins the basilar portion, is a protuberance called jugidar tubercle {tuberculum jttgulare). Backward and outward is a considerable furrow, which proceeds from behind forward, and from without inward ; this is called the groove of the transverse sinus {sulcus sinus transversi). Between this furrow and the process is the anterior opening of the pos/enor condyloid canal {canalis condyloideus posterior).

On the inferior face we notice a convex eminence, the condyloid process {processus condyloideus) which is directed from behind forw'ard, and from without inward. Before, above, and on the outside of this eminence, is the external opening of the anterior condyloid canal {foramen condyloideum anterius). Directly behind its posterior extreir^ity is the posterior opening of the posterior condyloid canal and the condyloid fossa {sinus condyloideus). Behind and on the inside of this opening, in the circumference of the posterior part of the lateral parietes.of the large occipital foramen, are well marked muscular impressions.

Internally, the articular portion is broad before, and presents an inner surface inclined from above downward and inward. Its internal edge is uneven. It forms the lateral wall of the large occipital foramen. Behindhand below the jugular tubercle, it presents the internal orifice of the anterior condyloid caned.

The external edge commences by the large jugular fissure {sinus jugularis), at the extremity of the fossa of the longitudinal sinus. Next comes a small eminence covered with cartilage, and called ihe jugular process {spina jugidaris), and then a slightly serrated edge {niargo mamillaris).

Backward, the condyloid portion is continuous with the proper occipital portion.

§ 534. This last portion, which several anatomists, as Loder, contrary to all analogy, have called the boely, curves from below and forward upward and backward. It is triangular, and seems formed of two portions, the inferior of which is broader than the superior, which unite at an obtuse angle.

The upper half of the external face is smooth, while the muscular impressions and the depressions render the lower half uneven. â–  The upper circuit of the latter is formed by the upper curved line {linea semilunaris superior), which is convex above, and extends from one side of the squamous portion to the other. Towards the middle of the inferior portion is a second semicircular elevation, the loiver curved line {linea semilunaris inferior), which extends as far as the preceding. This inferior half is itself divided into a right and a left portion, by a longitudinal eminence more or less distinct according to the individual, the external occipital crest {crista occipitalis externa), which always

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begins Aviih a greater and broader projection, termed the external occipital protuberance [spina occipitalis externa) ; this extends to the posterior edge of the large occipital foramen. The enlarged edge of the latter produces in some measure a third curved line, the occipital crest (crista occipitalis), concentric with the two preceding, and having the same uses.

The internal face of the squamous portion is divided by the crucial ridge (eminentia cruciata) into four nearly equal depressions. The upper half of the longitudinal branch of this eminence is the fossa of the termination of the longitudinal sinus of the dura mater (sulcus longitudinal is). The two transverse branches are the lateral fossæ

(sinus transversi), which receive the lateral sinuses. The falx cerebelli is attached to the internal occipital crest (crista occipitalis interna), which is that part of the longitudinal branch situated below the intercrossing, and so called because it projects more or less, and is seldom grooved. The fossæ are bounded by' two irarallel elevations. They are rarely symmetrical : in fact, the lower part of the longitudinal branch corresponds exactly to the median line ; the upper, however, rarely presents the same arrangement, so that the two lateral elevations, between which the fossa extends, descend at an equal distance from this line, and the centre of the fossa falls exactly yppn ^t, fossa more commonly separates to the right and left, apd' one of the edges descends along the median line ; and not unfcequeiqtly thè fossa extends to one side, so that its internal edge passes very far, 'sometimes even half an inch, beyond the median line ; hence, the.^d*féct in symmetry is much more evident. Most frequently, in two ôf every tlrree cases, the longitudinal fossa goes to the right j hedge .the'left transverse fossa is longer, but at the same time the rigiïjîî's^broâder. The latter is a direct continuation of the longitudinal* fossa, while the left joins the two by an oblique fossa. It sometimes . though rarely happens that one of the transverse fossæ follows the same direction as the longitudinal, so that the inferior extremity of the latter is uninterruptedly continuous with it ; but then the transverse eminence, which is single, occupies its usual place, even so that when the longitudinal fossa is turned very much to the left, the upper half of the longitudinal eminences is found on the median line.

The cerebellum is situated in the inferior fossæ, wdrich are hence called the inferior occipitcd fossæ, or the /ossÅ“ of the cerebellum (fossæ cerebelli). The superior fossæ receive the posterior portion of the lobes of the cerebrum ; hence they are called the cerebral or upper occipital fossæ (fossæ cerebrales). The former are often smooth ; sometimes, however, we find alternate elevations and depressions, which are convex above and concave below, forming a concentric, narrow, and plane series, which proceeds from the median line to the lateral edges,. The digital impressions and mammillary eminences of the infeiior fossæ are more rounded, straighter, broader, and more distinct.

At the place where the fossæ cross, the internal face of the squamous portion has a large projection called the inteimal occipital protuberance

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(spina occipitalis interna^ As Ihis protuberance corresponds to one on the outside, the thickness of the bone is greatest m this place, being sometimes half an inch.

/

• ^ / b. OF THE SPHENOID BONE.

§ 535.' The sphenoid bone occupies the middle and a part of the a^jferigr^egion of thd-diase of the skull, and a small part of, the lateral regions. /y .

It'is compos'ed'of a central portion, the hoày^ and several processes, spme of which are on the sides, and others below. This arrangement causes it to resemble a vertebra.

§.53&<The body is continuous posteriorly with the basilar portion of the occipital bone. Above this point it curves more or less upward and forward, so that the upper and unattached portion of its posterior face succeeds the upper part of the basilar portion (§ 530). This posterior face is veryrough, and its upper edge is more or less prolonged, to give origin to ihe posterior clinoid processes (processus clinoidei posteriores).

The upper face is nearly always distinctly divided into three successive parts. The posterior part is grooved in a transverse direction, and forms the sella turcica, in which the pituitary gland is situated. The middle, which is smaller, ascends more or less obliquely from behind forward; it is most generally a little convex or plane, and is rarely grooved. It is the crossing-place of the optic nerves. The aiiterior is horizontal.

The anterior edge of the upper face is seiTated, and forms in its centre a large projection.

The lateral faces descend slightly from within outward. On the limit which separates them from the superior face is a groove, the carotid groove (sidcus caroticus), which lodges the internal carotid artery. Near their anterior extremity, or on the limit between the inner and the upper face, we see on each side a more remarkable projection, in which the line of demarkation betweem the middle and posterior portions of the superior face terminates ; these are the middle clinoid processes {processus clmoidei medii). These processes sometimes unite, when largely developed, with the posterior and the anterior clinoid processes ; the latter union is more common than the former, and is sometimes seen alone, while the former never occurs without it.

The anterior face, which is slightly convex, is not always formed by a plate fused with the rest of the bone, but often by two distmet pieces of bone, which are very thin, and are called the sphenoidal horns (cornua sphenoidea). It is always imperfect at its upper part, and presents in its centre a longitudinal eminence called the sphenoidal crest (spina s. crista sphenoidalis).

The under face is slightly grooved. Forward and in its centre it forms a small, thin, longer or shorter eminence, called the sphenoidal beak (rostrum sphenoidale).

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DESCRIPTIVE ANATOMY.

The crest, and the beak of the sphenoid bone are more or less continuous with each other.

The body of the sphenoid bone is formed in the adult of very thin walls, and is hollowed into two large cavities, the sphenoidal sinuses {sinus s. antra sphenoidalia), a right a,nd a left, which are separated by a longitudinal partition, of which the crest and the beak are prolongations, and the surface of which is often increased by the projections which arise from it.

§ 537. The processes of the sphenoid bone are the large ivings {alÅ“ magnÅ“), or the middle processes {processus medii) ; the small wings {alee minores), or the superior j^rocesses {processus superiores) ; and the pterygoid or inferior processes {processus pterygoidei s. inferiores).

§ 538. The large wings arise below from the lateral wall of the body. At first narrower, they become broader forward and backward, curve forward and outward, and terminate in an upper and a lower point. Their form is triangular. Their concave face, which is turned inward, is uneven (§ 535); the anterior, which is square and also turned inward, is almost straight, or rather slightly concave. The external is convex from above downward, and a little concave from before backward. The inferior, a continuation of it, is straight. § 539. The upper, or the small wings, are much smaller than the preceding, and are lateral projections of the anterior part of the upper face of the body. They arise by two roots, an anterior and superior, which is thin ; a posterior and inferior, which is thicker. Their direction is forward and upward, but principally outward. They are flat and thin, convex and sharp before, concave and thicker behind, and terminate outward in a free point. The inner circuit of their posterior edge, is a tubercle, called the anterior clinoid process {processus clinoideus anterior). This process is opposite the posterior clinoid process. It often unites with the middle clinoid process (§536) ; by which arrangement there is behind the optic forarrien a second opening, situated at the anterior extremity of the carotid groove, and through which the carotid artery passes.

We less commonly find a third opening which results from the union of the middle and posterior clinoid processes.

It rarely happens that the anterior clinoid processes are united with the posterior, only by a long slip of bone.

All these anomalies occur on both sides more frequently than on one only.

§ 540. The lower, or the pterygoid processes detach themselves from the boundary which separates the inferior and lateral face of the body from the origin of the large wings, where the bone is thickest. They direct themselves from above downward, at the same time being inclined slightly outward. They divide posteriorly, soon after arising, and even at the place of origin, into two thin layers, called the pterygoid wings {lamhicc pterygoideœ), whicli are fused together in almost their whole extent forward. The internal, which separates

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them behind, is termed the pterijgoid fossa {fossa pterijgoidea) ; at their lower part, they separate also from each other forward, thus forming the pterygoid, or the ptery go-palatine notch {fissura pterygoidea, s. ptery go-palatina).

The inner and longer layer terminates in a rounded hook turned outwardly, called the pterygoid hook {hamulus s. uncus pterygoideus). As this hook is the continuation of the posterior edge, and as the anterior edge is equally prolonged, although a little less so, there exists between them a more or less considerable furrow.

The external layer, which is the shortest, terminates much higher than the preceding. At its summit, it curves inward, under the inferior face of the body, with which it is often intimately connected. This reflected part is termed the vaginal process {processus vaginalis) .

§ 541. In and between the different parts of the sphenoid bone are deep fissures, notches, and openings, through which the vessels, and especially the nerves, pass.

Between the two roots of the upper wing, we find the optic foramen, or more properly the optic canal {canalis opticus), which is short, rounded, and more broad than high.

Below this hole, between the upper and the middle process and the anterior part of the lateral face of the body, we remark a considerable irregular space of an elongated triangular form, broader inward and downward, and extending obliquely from without inwmrd. This is the sphenoidal fissure {fissura sphenoidea propria s. spheno-sphenoidea). It is usually open externally, because the point of the small wing does not touch the upper edge of the large wfing : but these two parts often touch, forming a true foramen.

The foramen rotundmn is found in the root of the great wing, below this fissure ; and it is separated from its inferior and posterior extremity by a small bridge of bone. It is a very short canal, which is continuous forward and backward with a semi- canal.

The posterior semi-canal unites more or less evidently with a much larger opening, near the posterior angle of the large wing. The direction of this is from above downward ; it is situated much more behind and outward, and is called Ûie foramen ovale.

Between the foramen ovale and the foramen rotundum, we sometimes find a much smaller hole, which also penetrates the large wing from above downward.

Directly behind the foramen ovale, and outside of its external extremity, the large wing is always pierced from above downward by another /oramew, the spheno-spinous {foramen spinosum).

Finally, the vidian or the pterygoid canal {canalis vidianus) passes through the substance of the sphenoid bone to where the large and small wings are detached from the body, immediately below its division. Its direction is from before backward, from below upward, and from within outward.

§ 542. The history of the development of the basilar bone is very complex, because each of its two parts, which are still separate from

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EESCKIPTlVn anatomy.

each other hut a little time before the wliole organiani is perfectly developed, are successively formed by a considerable number of osseous nuclei.

§ 543. The occipital portion appears long before the sphenoidal portion. According to our researches, it is usually formed by eleven points of ossification, which gradually develop themselves ; eight for the squamous portions, (1) the other three for the articular and basilar portions. The rudimenfof the squamous portion begins to show itself at the second month, directly behind the large occipital foramen, in the form of a pair of triangular nuclei, separated in the middle. These two osseous pieces fuse together. At the same time, a second pair appears, situated upward, corresponding to them in form, and representing the upper half of the squamous portion ; these also, at the fourth monlh, unite with each other, and also with the inferior pair, except in the region of the jugular tubercle, where a sensible opening still remains. About the same period, we find a third pair, situated outward and upward, on the sides of the second ; while this unites to the last, a fourth forms in the highest part, above the second. Thus the same formation is thrice repeated, until all the pieces are united, which most generally happens sooner or later, but sometimes never takes place. The squamous portion is usually formed at the fifth month. We, however, remark on each side of the fetus at birth, frequently even much later, one suture extending from the upper extremity of the serrated edge, and following the jugular process, inward and upward ; a second, which goes directly downward, from the upper extremity of the bone ; and a third, which proceeds exactly upward from the lower edge of the squamous portion. These three sutures indicate that the squamous portion is composed of several pieces, which often remain msulated during life, and are then called the loormian bones (ossa wormiana s. triquetra).

The condyloid jxirlions appear a little later than the squamous portion, but always earlier than . its upper part. They first show themselves as small, single, oblong and rounded osseous nuclei. The middle basilar portion is ossified the last.

These four portions fuse together in the same order as that in which they were ossified. The squamous part is separated from the rest long after its different nuclei are united in a single bone. In the full grown fetus the occipital portion is still formed of four pieces, of which the two condyloid portions are united before with the basilar portion, behind with the squamous part, but in no place with each other. This insulation remains even after birth, for we have seen it in a subject seven years of age.

As in all the vertebrae, the posterior part of the ring is developed the soonest, since the pieces of the squamous portion are first united, then

(1) Without doubting' the existence of four pairs of germs in (he squamous portions of tile occipital, or proral bone, Bedard asserts that this arrangement, far from being constant, should be considered a rare variety. He admits but four points of ossification in this portion. F. T

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tins portion joins the two condyloid portions, and these last three have long been united when the basilar portion is still entirely distinct. The marks of separation between the condyloid and the squamous portions disappear internally later than they do externally ; the contrary rarely happens.

§ 544. The sphenoid portion ossifies much later than the occipital portion. The osseous nuclei first appear in the third month of pregnancy in its two large wings ; next, one forms for each internal layer of the pterygoid processes. Afterward, we see a third pair of osseous germs in the circumference of the small wings ; then, at the age of eight months, a seventh and eighth nucleus which are fitted to one another in the body. At five months, a fifth pair forms near this fourth pair, between it and the large wing. The two middle nuclei of the body then fuse with each other. A sixth pair is soon developed at the internal part of the circumference of the optic foramen; finally, a seventh appears between this and the fourth. Thus, towards the beginning of the seventh month, the sphenoid portion is composed of thirteen distinct nuclei, since although seven pairs of nuclei are formed, the first two germs of the body are already united.

After this period, the number of osseous nuclei continues to diminish as they unite. The nuclei which unite first are those of the parts of the sphenoid portion, which still continue for a long time to form so many separate pieces ; thus the fourth, the fifth and the seventh pairs become one ; the first and the second become the second and third ; the third and the sixth, a fourth and fifth ; whence it follows that at eight months, the spheiroid portion is composed of five pieces, the two large wings, the anterior wings, and the body. In a short time the anterior wings unite, and the bone is then formed of four pieces only, next the body and anterior piece unite, so that in the fullgrown fetus the sphenoid portion comprises three pieces, because the large wings and the pterygoid processes are still separated from those of the centre. These three pieces unite during the first months after birth.

The body and the large wings are very rarely united before joining with the small wings, already blended with each other ; then, the sphenoid portion is composed of two parts, an anterior, which is larger, and a posterior, which is smaller. This anomaly is certainly very remarkable, because it coincides perfectly with the arrangement existing in most mammalia during the whole period of existence.

The body of the sphenoid portion is full and solid for a long time after birth. The sphenoid sinuses are however gradually developed, 1st, because the bonj^ substance disappears in the middle ; 2d, because a special layer of bone, called the sphenoidal horn, forms on each side, and from below upward ; this seldom remains distinct, but is generally fused with the sphenoid bone, rarely with the ethmoid or palate bone.

The sphenoid bone is thus gradually developed by sixteen, and the basilar bone by twenty-seven points of ossification.(l)

(1) See, on this subject, our Considérations analomigues et physiologiques sur les pièces osseuses qui enxcloppent les parties centrales du système nerveux, et sur leurs

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DESCRIPTIVE anatomy.

§ 545. The occipital portion of the basilar bone articulates backAvard and upward with the parietal bones, in most of its extent, AA'hich gives rise to the lambdoidal sutm'e. At the place where the parietal bones cease, the articulation of the mastoid portion of the temporal bone Avith the lower extremity of the squamous portion and the posterior part of the condyloid portion of the occipital bone, commences ; this produces the mastoid suture, at the end of Avhich the jugmlar process joins the posterior part of the internal edge of the petrous portion of the temporal bone. IVe then find between this last and the condyloid portion a space for the sinus of the jugular vein. Finally, the external edge of the condj-loid and of the basilar portion unites, by a fibro-cartilage, Math the anterior part of the internal face of the petrous portion of the temporal bone.

The sphenoid portion articulates A\âdr the summit of the petrous portion of the temporal bone, by the posterior edge of the large A\-ing by a broad layer of fibro-cartilage, and ' by the sphenoidal spine by means of a suture ; A\iih the anterior edge of the squamous portion of the temporal bone, by the internal edge of its large Ming ; Math the frontal bone above, and Math the malar bone beloM-, by the anterior edge of this same Ming. BetM-een the loAA'er edge of the anterior face of the large wing and the posterior edge of the upper face of the body of the superior maxaUary bone, M-e find the spheno-maxUlary or inferior sphenoidal fissure {fissura spheno-maxillaris, s. sphenoidea inferior), M'hich is applied at an acute angle backward, inAvard and upM'ard against the sphenoidal fissure. The upper edge of the anterior and internal face of the sphenoid portion, articidates Mith the posterior edge of the orbital portion of the frontal bone. Where the large AA'ing separates beloM- to form the inferior edge of the upper sphenoidal fissure, the suture is continuous betM-een the small Ming and the frontal bone.

Where the frontal bone terminates, the anterior edge of the body of the sphenoid portion articulates A\ith the posterior edge of the cribriform plate. The posterior edge of the perpendicular plate of the ethmoid bone lies along the sphenoidal crest, and the beak of the sphenoid bone insinuates itself into the cleft of the vomer. Finally, the perpendicular portion of the palate bone descends, in fi'ont, on the inside of the internal plate of the pterygoid process, and its pyramidal portion insinuates itself into the pterygoid fissure.

In this manner the basilar bone articiilates Math aU the bones of the skull, and M'ith five of those of the face.

§ 546. The occipital portion of the basüar bone presents numerous and very various anomalies, M hüe those of the sphenoid portion are rare, and of an entirely opposite character. The original defects of formation of the former consists essentially in its diArsion into several pieces ; this anomaly is most common in its squamous portion. The least anomaly is the existence of a greater or less number of small bones in the lambdoidal suture. We not unfrequently find one of them at the summit of this sutmre, M'here it results from a want of

annexes, in the Journal complémentaire du Dictionnaire des sciences médicales, vol. i.p.211. Spiv has arrived at the same conclusion as ourselves, (Cephalogenesis,p.\l .)

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union of the last pieces of which the squamous portion is composed with the others. It is less frequent that the third piece, on one or both sides, is not united, and forms a large bone, which descends obliquely in the lower part of the lambdoidal suture.

More rarely still the second pair remains separated fr'om the first which is the lowest, by a suture passing obhquely through the middle of the squamous portion.

Finally, the rarest anomaly is where a longitudinal sutirre traverses all the height of the squamous portion fi'om the angle of the lambdoidal suture to the large occipital hole, and divides it into two lateral portions.

So, too, the condyloid portions seldom remain a long time separate from the squamous and basilar portions ; still less do they continue distinct during life.

The condyloid portions and the basilar process vary from the normal state, principally by the existence of unusual processes, which are directed from above downwards, and are often considerably long ; these exist most generally near the occipital foramen, either on one or both sides, and are more or less firmly articidated with the transverse processes of the fir'st cervical vertebra. These processes are much more rarely found before the occipital foramen, between the anterior extremities of the two condyles.(l)

II. OF THE TEMPORAL BONES.

§ 547. The temporal bones {ossa temporim) (2) are situated on the sides of the head, and are separated from each other below by the basilar bone, and above by the parietal bones. They occupy part of the middle region of the base of the skull, and the inferior part of its lateral faces. We distmguish in it a part which is more sohd and thick, and which may be compared to the bodies of the vertebrae, and the lateral parts, or the arches, from whence processes arise. Each of these bones, however, only represents the half of a vertebra. The rock, ox petrous portion (pars petrosa) is the body ; and the squamous portion {pars squamosa), which reaches above the last, is the arch. Usually, this bone is divided into three parts, — the squamous, Ûxq petrous, and the mastoid portion. The last, however, is only an appendage of the second.

§ 548. The most important part of the temporal bone is that which corresponds to the body of the vertebræ, — the petrous portion, and is so called from the hardness which characterizes it when perfectly developed. It is also called the pijramid, from its triangular form. Its base is turned outward and backward, its summit forward and inward. One of its three faces looks forward and upward, a second backward and inward, and a third downward. The first and the second are separated

(1) Meckel, De rhonstr. duplic. p. 24 . — Deutsches Archiv für die Physiologie, vol. i. part iv. p. 6.

(2) We shall not mention here the internal structure of the temporal bone, nor the little bones of the internal ear. These will be described when speaking- of the organ of hearing.

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DKSCRIPTIVE ANATOMY.

from each other by the upper, the second and the third by the inner, the third and the first by the outer angle.

§ 549. The internal organ of hearing is situated within the petrous portion. The internal carotid artery passes through it to penetrate the skull, and the facial nerve to go to the face. On its surfaces and edges we can trace these two passages. We see also others which correspond to the anastomoses of the nerves, and to the venous sinuses of the dura-mater.

§ 550. The most important of these marks relate to the organ of hen ring.

Near the centre of the upper face, we find a large transverse ridge, formed by the projection of the upper semicircular canal of the labyrinth, which is here naked during the early stages of uterine existence, at winch period it is not yet covered with a plate of bony substance ; and we remark above it a deep fossa, which receives the dura-mater, the traces of which are gjaduaily effaced after birth.

In the middle and forward, we see on the internal face a considerable rounded opening, depressed from above downward, in which the auditory and the facial nerves are situated. This is the iniernal auditory foramen {porus acusticiis internus). This opening leads into a cavity, divided by a transverse portion into two openings ; a superior, which is smaller, and an inferior, which is larger ; the former leads into the Fallopian canal {aqueductus Fallopii) by several openings, the other to the labyrinth.

Below this opening, on the boundary between the inner and the lower face, we find the triangular orifice of the aqueduct of the cochlea; behind which we see, at the same height, the orifice of the aqueduct of the vestihide, which is turned back and flattened.

On the limit between the upper and the lower face, are two imperfect bony canals, separated from each other by a bony projection.. The inferior, which is also larger, is the osseous portion of the Eustachian tube {tuba Eustachiana ossea). The upper is smaller, and gives attachment to the tensor muscle of the membrane of the tympanum {musculus tensor tympani).

The external portion of the inferior face, which is the most extensive, forms an elliptical canal, the osseous portion oj the auditory passage {meatus audit orius osseus), which opens externally by a broad orifice, called the external auditory foramen {foramen s. porus ßcusticus externus).

The Fallopian canal proceeds first obliquely from above dowmward, and from within outward ; then from Ijehind forward, and from below upward, to arrive at the inferior face, where it terminates in the stylo-mastoid foramen {foramen siylo-mastouleum). It gives passage to the facial nerve.

On the upper surface, along and over the canal for the tensor tympani muscle, is a fissure leading to a canal which opens with the aqueduct'of Fallopius.

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At the anterior extremity of this surface, above and within the anterior orifice of the carotid canal, we observe a semicircular and superficial depression, which corresponds to the nerve of the fifth pair.

§ 551. The traces of the vessels are, 1st, the canal of the internal carotid artery {canalis caroticus internus), which curves from below upward and from within forward, of which the external orifice {foramen caroticuni externum inferius) is found in the centre of the inferior face, while the internal {foramen caroticuni anterius s. siiperius) is seen at the summit of the superior face, where, /his canal, deprived of its upper wall in a considerable extent, forms in reality only a semi-canal.

2d. On the inferior surface, directly behind the orifice of-the aqueduct of the cochlea and the posterior opening of the carotid canal, is a more or less extensive fossa {fossa hidbi venÅ“ jugularis internÅ“), for the sinus of the internal jugular vein ; a fossa which communicates by fissures with the two aqueducts.

3d.. Aj the upper angle, tl^e fissure of the superior jietrous sinus {sulcus^petrosus superficialis) .

4th. On the internal surface of the mastoid process, the fissure of the transverse sinus {sidcus sinus transversi), which is generally directed very far forward and upward, and occupies most of this surface. Very rarely, this fissure is very small, or is even entirely deficient, when the transverse sinus, varying from its usual rout, descends entirely or almost entirely on the occipital bone alone, or follows a longitudinal direction. Of more than fifty well developed temporal bones before us, the fissure is entirely deficient in but one, and extremely small in two only.

5th. We generally see on its posterior face, a little above the centre, the mastoid hole {foramen mastoideum), the internal orifice of a canal which usually extends some lines within the bone, and commences on the boundary between the mastoid portion and the occipital bone, or on the outer face of the mastoid portion.

§ 552. The muscular eminences and depressions are,

1st. The styloid process {processus styloideus), at the posterior extremity of the under edge of the pyramid ; this varies much in length, and sometimes exceeds two inches. This lorocess is sometimes entirely free, and is often composed of several pieces — a curious analogy with animals. It arises between two broad, fiat, bony processes, called the vaginal processes {vaginæ processus styloidei).

2d. Behind the styloid process is the conical mastoid process {processus mastoideus) . The stylo-mastoid foramen {§ 550) {foramen stylomastoideum) is situated between these two eminences.

3d. Behind the mastoid process is the mastoid fissure {incisura stylomastoidea) .

§ 553. The squamous portion is slightly rough on its outer face for the insertion of the temporal muscle. Forward and downward the external face extends in a thin process, flattened from without inward, called the zygomatic jn'ocess {processus zygomaticus jugulis), and of which the external and longer root is placed over the external auditory foramen, the orifice of which it closes above, while the lower, which is

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DESCRITTIVE anatomy.

transverse, and called the articular eminence {tuber articulare), is found ' before the transverse articular cavity {cavitas articularis) of the lower maxillary bone. Anteriorh', it circumscribes this catity \nth which it is insensibly continuous. Behind, the cavity is bounded by a transverse projection, situated before the anterior part of the osseous auditory passage, but entirety separate from it, and which varies much m thickness and height.

Advancing from beliind forward, the zygomatic process separates a little from the squamous portion, and its anterior extremity reaches over the anterior edge of the same.

The internal smface of this portion of the temporal bone presents digital impressions and mamillary emhrences, and generalty, at its upper parr, a transverse arterial fissure.

§ 554. In the full-grown fetus, the temporal bone is formed of four pieces of bone, the petrous^ the mastoid, and the squamous portions, and the ring of the tympanum {anmdus membranœ tympani). This last is the onty vestige of the osseous auditory canal. It is elliptical in fonn, longer from above downward than from before backward, is not entfrely closed at its upper part, is attached to the petrous portion immediately before the carity of the tympanum by almost its whole external cfrcumference, and to the lower part of the squamous portion by its tAvo upper extremities, is broader and thicker before than behind, and offers, at its internal chcumference, a deep fissure, in Avhich the membrane of the tympai^um is mserted.

Some ti^re after birth, these four parts are fused together. The separation Avhich existed betAveen the upper extremities of the ring of the tympanum and the squamous portion disappears first. The trace of separation A\-hich continues the longest is betAveen the petrous and the squamous portions, especially on the mternal face ; for, although the marks of separation betAveen the squamous and the mastoid portions disappear entirely on the outside, Ave see through life a suture which exists, in most of its length, betAveen the mternal face of the squamous, and the upper face of the petrous portion. This suture, called the squamo-pijra^idal suture {sutura squamoso-pyramidalis), extends forAvard, AAmere it is called Ûx& fissure oi Glaser {Fissura Glaseri), passes mtder the articular cavity, before the bony portion of the auditory canal, through all the substance of the bone, and terminates in the caATify of the tympanum.

The ling of the tympanum gradually enlarges, and unites with the petrous portion on all èides, and, increasmg out of proportion Avith the other parts of the bone., from a simple ling rounded and flattened from A\tithout inAvard as at first, it becomes a canal half an inch long and compressed from before backAvard, the osseous portion ofi the auditory canal, w'hich remams hoAvever for a long time imperfect and cartilaginous at the loAver part of its circumference, backAvard.

HoAvever, the petrous and squamous portions increase also very much, by the development of the mastoid process. At the same time, the squamous portion is not only higher, but becomes more convex ex

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ternally, instead of being straight as hitherto. The zygomatic process also changes its form ; it throws itself outward, separates very much from the squamous portion, and extends beyond its anterior edge in the same proportion. A remarkable change supervenes also in the situation of the glenoid cavity and of the articular process, which, previously plain, very broad fi'oin before backward, and very obhque from above downward and fi'om without inward, become almost transverse, and are considerably developed, wirich gives more firmness to the tern • poro-maxillary articulation,

§ 555. The temporal bone articulates, 1st, by its mastoid, petrous, and squamous portions, with the basilar bone behind and forward. 2d. By its mastoid and squamous portions above, with the inferior edge of the parietal bones. The first articulation is by a serrated suture, and the secoijcl by the squamous suture (S. squamosa), the twm bones gradually becoming thin to the extent of from four to six lines, and fittmg to one another, so that the squamous portion covers the parietal bones. 3d. The temporal bone articulates with the malar bone by a dentated suture, and 4th, with the lower maxillary bone which moves upon it, by hgaments.

III. OF THE PAPHETAL BONES.

§ 556. The parietal bones {ossa hregmatis, s. verticis, s. panetalia'), are only portions of a vertebra. We ought to consider them as the complements of the lateral parts of the temporal bones and of the sphenoid bone, between which they are wedged in. They stand together on the median line and are often imited in a single bone, They occupy the upper part of the lateral faces and the summit of the skull, have an almost regular quadrilateral form, and are flat in every part.

§ 557. The edges which circumscribe them are the upper, inner, or sagittal edge (^margo sagittalis), the anterior, frontal, or coronal edge {inargo frontalis, s. coronalis), the inferior or squamous edge {margo squamosus), and the posternor or occip>ital edge {margo occipitalis). The angles formed by the union of these four edges are called, the upper and anterior or the frontal angle {angidus frontalis), the upper, posterior or the occipital angle {angidus occipitalis), Xheloiuer and ante,rior or the sphenoid angle {angulus sphenoideits), and the loicer and posterior or the mastoid angle {angulus mastoideus).

§ 558. They appear especially on their outer face, and, more particu' larly, in young subjects, formed very distinctly of two portions, united at an obtuse angle, the upper, which is larger, and the inferior, w'hich is smaller. The skuU is broadest where these twm portions join ; this partis called the parietal protuberance {tuber parietale). The Upper is smooth, the lower is slightly uneven, and separated from the other by an arched rim, whence it has been called the semi-circular surface {planum semi-circulare) .

The internal face,_beside3 the usual cerebral and digital impressions, presents ascending and branching channels, which lodge arteries and

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DKECIIU'TIVE ANATOMY.

veins {sulci meningei), called, from their arrangement, the ftg-lcaf. We also remark, especially in old subjects, along the upper and internal edge, slight depressions { foveÅ“ glandidares), which sometimes extend even to the external table. At the inferior and posterior angle, a transverse furrow {sulcus iransversus), constantly exists and completes that seen on the occipital and temporal bones (§ 551) ; along the sagittal edge is a slight fossa, which, united to that on the opposite side, forms the/ossa of the upper longitudinal sinus {sulcus sinus longitudinalis).

Near the sagittal edge, we usually perceive on one or both of the parietal bones,' the parietal foramen {foramen parieicde).

§ 559. Each parietal bone develops itself by a single point of ossification, which first appears in the parietal protuberance.

§ 560. These bones articulate with each other upward and inward, along their upper edge, by the sagittal suture {suture sagittalis), which goes directly from before backward on the median line ; backward, with the occipital bone(§555) ; downward, with the temporal bone, by most of their squamous edge, and with the large wing of the sphenoid bone (§ 555) by the rest of this edge, as also by the sphenoid angle ; finally, with the frontal bone, by their anterior edge and by the coronal suture {sutura coronalis).

§ 561. The sagittal suture is sometimes wholly or partially effaced, and the two parietal bones become one, although all the other bones remain separate and distinct.

On the other hand, we sometimes, but much more rarely, see one or both of them divided by a transverse suture into an upper and a lower portion. ,We do not know that they are ever divided by a longitudinal suture into an anterior and a posterior portion.

IV, OF THE FRONTAL BONE.

§ 562. The frontal or the coronal bone {os frontis) occupies the anterior part of the skull. It corresponds to the squamous and condyloid portions of the occipital bone. We observe also, in the place corresponding to the large occipital foramen, an analogous opening, which however is not closed behind, because the frontal bone has no basilar proeess. Perhaps this last is represented by the body of the sphenoid bone.

§ 563. This bone is divided into a frontal portion {P. frontalis), an orbitar portion (P. orhitalis), and a nasal portion {P. nasalis).

§ 564. The frontal portion is by far the largest. It corresponds to the squamous portion of the occipital bone in form and situation. Like that, it is composed of two parts, united at an obtuse angle, the upper being more extended than the lower. Where both of these join is the part where the bone projects the most, and presents on each side the frontal tubercle {tuber frontale). Below these eminences, we find on each side also, directly above the upper edge of the orbit, and inward, another protuberance separated from it by a depression, called the superciliary ridge {tuber superciliare, supra-orbitale), where the two

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tables of the bone are separated from each other to form the frontal sinuses {sinus frontales). The triangular space on the median line which separates the two ridges is called the glabella. But a small extent of the region of the anterior face, that which looks a little outward, and completes the semicircular surface of the parietal bone (§ 558), is rough.

The inner face is divided into two lateral parts by the frontal crest {crista frontalis). This, which is found on the median line, forms sometimes a very considerable projection, and terminates upward by a furrow, the commencement of the longitudinal fossa {sulcus loiigitudinalis). These two portions are uneven, like those of the internal face of the parietal bones.

§ 565. The orhitar 'portion, which unites with the preceding at a right angle, is separated from it externally by a projecting and round edge called the orhitar arch {margo superciliaris, s. supra-orbitalis). At the internal extremity of this edge passes the frontal fossa or canal {sulcus s. canalis frontalis), exïending from the under face of the orhitar portion to the external face of the frontal portion. This edge enlarges outwardly, as does also the inferior part of the anterior face of the frontal bone, to produce the short Wt strong malar protuberance {tuber jugate).

The orhitar portion, which forms the arch of the orbit, is contracted from before backward, convex upward on the side of the skull, concave downward on the side of the orbit, and very thin. At the internal part the two tables separate from each other (§ 564).

The inferior face presents, outward and forward, the lachrymal fossa, which is usually superficial ; inward and forward, a small eminence or depression, called the trochl trochlearia).

§ 566. Between the frontal and orhitar portion is the nasal part, which is properly only the most internal part of the two others, and is in the form of a horse-shoe. It is composed of two portions, which unite anteriorly in an arch below the middle of the fi'ontal portion, and the tables of which, very widely separated, especially iir front, contain the access to the frontal sinuses, aird are separated by the ethmoidal fissure {incisura eihmoidalis) . The nasal spine {spina nasalis), which often forms a separate piece of bone, arises from their place of union. Between this spine and the inferior extremity of the frontal crest, we observe a considerable opening, improperly called the foramen cæcum.

§ 567. The froirtal bone is developed at the second month in two lateral pieces, separated longitudinally on the median line, the union of which generally begins during the first year, and is finished toward the end of the second. These two pieces by their mutual articulation produce the frontal suture {sutura frontalis), which has the same direch tion as the sagittal suture, and whose lower part is always effaced the last.

§ 568. The frontal portion of the frontal bone articulates above, 1st, with the parietal bones, by the coronal suture {sutura coronalis) (§ 560) ; 2d, the orbitar portion articulates downward and backward

mr spine or fossa {spina s. fovea

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DESCRIPTIVE ANATOMY.

with the small and large wings, as well as with the body of the sphenoid bone (§ 545), by the malar process; 3d, with the malar bones (§ 595), by the lateral parts of the nasal portion ; 4th, with the ethmoid bone (§ 574), by the anterior part of this portion and by the nasal spine ; 5th, -with the proper bones of the nose ; and 6th, on the outside of these with the upper maxillary bones.

§ 569. The most usual anomaly presented by the frontal bone, and which is not rare, consists in the want of union of its lateral portions. The frontal suture then remains during life. More rarely the frontal sinuses are not developed.

V. OF THE ETHMOID BONE,

§ 570. The ethmoid or cribriformhone {os elhmoideum B.crihriforme) is found at the anterior and middle part of the base of the skull. It slightly resembles a vertebra in its thin and perpendicular middle layer, and in its two lateral portions, which are folded on each other in different ways. We might rather consider it a bone of the face, and more so because it is wedged in between these bones, among which are numbered some not more perceptible externally than this, and resembling it in form and functions.

§ 571. We distinguish in the ethmoid bone a central and two lateral portions. The first is formed almost wholly by a jjerpoidictdar plate {lamina perpendicularis) much higher in its anterior than in its posterior portion. Behind, where Jhe posterior portion terminates, we see detached from its upper edge a horizontal layer, called the cribriform plate {lamina cribrosa), which extends on both sides. This plate is placed along the perpendicular plate, the upper part of the anterior portion of which consequently rises much above it. This latter, called the crista gcdli process, projects within the cranium ; it is much thicker than the part below.

The cribriform plate presents two series of oblong openings, the largest of which are situated inward, along the crista galli process and in the same direction from before backward, while the smallest are found along its external edge. The anterior and middle are the largest, and are oblong, often three or four lines in extent. Between these two ranges are others, which are smaller and irregular.

All these are the tunnel-shaped orifices of small canals ; the internal pass several lines along the lateral faces of the perpendicular plate, and then divide into others which are smaller, and degenerate into simple fissures, which descend very low in the septum. •

§ 572. The lateral portions of the ethmoid bone, or the labyrinths {labyrinthi), are extremely thin and complicated. Each generally represents a quadrangular cavity, which is longest from before backward, and shortest from within outward. The upper vnill is generally partially or wholly deficient, and is covered by the sides of the nasal part of the frontal bone, which serves as a top to it ; the anterior.wall is also open. The outer side is sometimes, but more rarely, imperfect : it is smooth and straight, and is called the os plarmm, or lamina

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papyracea^ because it has the smoothness of parchment. The inferior wall is very uneven ; the posterior is deficient ; the internal is straight, and rendered uneven by the external range of openings found on the cribriform plate, as also by the*'descending canals and fissures which penetrate its substance by small openings. Posteriorly, this internal wall forms two projections placed one over the other, separated by a deep space, convex within and concave externally, called the upper and middle turbinated bones {concha superior et media). The latter turns on itself anteriorly, hence it is convex externally. The lower turbinated bone forms the inferior wall of the labyrinth.

Transverse, irregular, and partly imperfect plates proceed from the outer to the inner part of the labyrinth, forming a greater or less number of ethmoidal ceUtdes {celhdœ ethmoidales). The anterior cells are also called the orbital or lachrymal (C. or'hitai'iœ s. lachrymales), the middle, the frontal (C. frontales), and the posterior, the palatine (C. palatince).

From the upper edge of the middle turbinated bone a transverse septum proceeds to the posterior edge of the os planum, and closes, but imperfectly, the middle cellules.

This septum and the os planum are extended backward and downward at their anterior and inferior angle into a thin, sometimes a slightly curved process, called the small ethmoidal process {processus minor). Another arises farther forward and inward, from the anterior part of the labyrinth and the transverse septa of the anterior cellules, between the anterior extremity of the middle turbinated bone and the os planum. This varies much hr length, and is called the large or unciform process of the ethmoid bone {jjrocessiis major, s. unciformis, s. haimdus).

§ 573. The ethmoid bone is not developed till the fifth month. The lateral portions appear first, and the middle part is not formed till after birth.

In the full-grown fetus, this middle part is entirely cartilaginous ; the two lateral portions are separated from each other, and but slightly developed, for the external and the internal walls almost touch. However, the eminences we have mentioned, already exist, although, even relatively speaking, much smaller. The cribriform plate is very broad, and broader in young children than in adults; it contracts when the. internal and external walls of the labyrinth are separated from each other. Even long after these three parts are fused together, the middle, which ossifies from above downward, continues to be almost cartilaginous. Its inferior and anterior part, which belongs to'the cartilaginous septum of the nose, always retains this character.

§ 574. The ethmoid bone is articulated ; 1st, forward and upward, by the anterior edge of its perpendicular plate, with the middle nasal portion of the frontal bone and the posterior edge of its nasal spine ;2d, upward, on each side, by the upper wall of the labyrinth, with the nasal and orbitar portions of the frontal bone ' 3d, before, and on the side with the unguiform bone ; 4th,- iljy the posterior edge of its cribriform plate, and by its perpendicufe.r plate, with the middle edge

430

DESCRIPTIVE ANATOMY.

of the upper face of the body of the sphenoid bone and with the sphenoidai spine ; 5t.h, by the posterior part of the labyrinth, with the palate bone; Glh, by the inferior edge of the os planum, with the body of the superior maxillary böue in the orbit, and by the anterior part of the labyrinth, with the ascending process of the same bone in the nasal cavity ; 7th, by the inferior edge of the septum, with the vomer; 8th, by the anterior part of the labyrinth, with the nasal bone ; 9th, finally, sometimes by its large process with the inferior turbinated bone.

§ 575. The os planum sometimes divides into several distinct laminæ, which are generally situated one behind another'.

CHAPTER II.

OF THE BONES OP THE FACE.

§ 576. The/ace is composed of fourteen bones. We may, however, oppose the region of the upper jaw to that of the lower jaw ; for, 1st. The different bones which form the first, are united by the suture which admit of no motion, while the lower maxillary bone is articulated so as to play freely. 2d. Most of the bones of the upper maxillary region may be considered as the appendages of one large piece, the upper maxillary bone. 3d. The lower maxillary bone is not, in many animals, a single bone as in man, but is composed of several, and often of a great number of bones.

§ 577. Most of the bones of the region of the upper maxillary bone, are in pairs. Of these, there are six, viz. 1st, two upper maxillary bones ; 2d, two palate bones ; 3d, two malar bones ; 4th, two 7iasal bones ; 5th, two lachrymalhones] 6th, two tm'hinatedhones]7(h,{h^vomeris a single bone. Both Lietaud and Portal have remarked, after tlie ancient anatomists, that the vomer usually unites early with the ethmoid bone, so that connecting these together we have then only six pairs to describe with the superior maxillary bone. The region of the lower maxillary bone is composed of a single bone. In the face, as in the skull, the unmated bones are situated on the median line, or are composed of two lateral corresponding portions.

§ 578 All these bones are not developed by a single point of

• ossification, but their different osseous nuclei unite, the lateral portions

of the lower maxillary bone excepted, long before those of the skull, and generally before those of most bones ; perhaps, because they are smaller, and not like the pieces of the skull and vertebral column, liecause immediately connected with air organ, in which the formative power exerts all its energy.

I. OF THE UPPER MAXILLARY BONES.

579. The upper 7iiaxilla'ryJ)one.s (o.s.sa maxillaria, s. maiidilmlai'ia superiora, s. inaxillœ siiperioi^ principally determine the form of the

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whole face, because they are the largest, and are situated in the centre of the others.

Their form is almost quadrilateral. We usually distinguish a body and four processes, inclining upward, outward, downward, and inward.

The upper face of the body is smooth; its direction is obliquely downward, outward, and a little forward. We generally observe from before backward, a semi-cai^l, Operr at its upper part, and extending from the posterior edge to about its centre ; this is continuous, after leaving this point, with a perfect canal called the infra-orhital canal {sulcus s. canalis infra-orbitalis) which passes below it, to open oir its anterior face. The track of this carrai is generally indicated also at the upper face of the body of the upper maxillary bone, by a very rrarrow fissure, which does not, however, always extend there, although it did originally. More rarely, this duct forms in its whole length a perfect canal ; and then, sometimes the fissure exists iir its whole extent, and sometimes it is entirely deficient, but oirly in the place where it is found in the normal formatioir. Sometimes also, this fissure is occasionally interrupted, iirdependent of the arrangement of the posterior part of the duct. Finally, it often happens that the semi-canal is extended very far, almost even to the anterior edge of the upper face. These differences are worthy of remark, as they indicate the different degrees in the development of the bone.

§ 580. On the upper face, we generally see upward and inward, the extremity of the fissure described, which leads to the infra-orhital foramen. This hole is rounded, terminates sharply above ; while, below, it is prolonged into a more or less deep depression, and is not far from the anterior edge of the upper face. Sometimes, but rarely, instead of one foramen, there are several : we then find, at a greater or less distance from the usual large foramen, another opening, which is smaller and situated more inwardly ; in which case, the canal is divided sooner or later into two branches. In certain cases, the two holes are more than half an inch apart, and the canal is divided at its posterior extremity ; differences which are remarkable as establishing an analogy with the formation'of the simiæ and cetaceæ.

Below the infra-orbital foramen, we find a deep muscular impression, the maxillary fossa {fossa maxillaris).

The posterior part is convex, and presents below the maxillary protuberance {tuber maxillare).

The inner part is very uneven. We remark anteriorly and about its centre, the inferior turbinated spine {spma turbinalis inferior), an eminence almost straight, which, however, descends a little obliquely forward, ami is very rough. We then see the lachrymal groove {sidcus lachrymalis), which goes downward and backward from the upper edge, and is sometimes changed into a canal in a small part of its extent, when its anterior and posterior edges touch. Further still at the upper part of this face, a large hollow occupies a part of it, which extends almost to the posterior edge, and leads into the antrum Highmorianum.

432

DESCRIPTIVE ANATOMY.

The body is hollow, and its walls, especially the upper, are very thin. The viaxillanj sinus, or the antrum Highmoriauum [antrum maxillare, s. Highmori), which is within it, and opens into the nasal cavity by its internal wall, is often curved with eminences which render its surface uneven.

§ 581. The ascending, upper or 7iasal jyrocess [jwocessus asceiidens, s. 8upe7'ior s.?/as«/is), leaves the anterior and .internal angle of the upper face of the body, and is flattened from within outward. The posterior and smaller part of its external face is separated from the anterior by an eminence sharper below than above, and is continuous with the upper anterior edge of the body. This part is hollowed out, and forms the beginning of the lachnjmal groove. Its internal face is a little concave, and we see on it, near the middle, the ethmoidal spine [spina etiimoidalis), parallel to the inferior turbinated spine ; sometimes when the nasal process is very broad, it is divided by a sharp crest into an anterior and a posterior portion, the latter of which is much more hollowed, and assists in forming the anterior cellules of the ethmoid bone.

§ 582. The palatine process [processus palatinus) detaches itself from most of the inferior edge of the internal face, at a right angle, and goes horizontally inward. Its upper face is smooth, and the under is rough. It terminates backward by a serrated edge, inward by an uneven and broad surface, especially at its anterior part. It is continuous forward with the alveolar process. In this place it is traversed from above downward, and from behind forward, by the palatine or incisony chan^iel [canalis palatinus s. insicior), which usually forms only a simple semi-canal, because its internal wall is deficient, as is the entire length of the external wall, from which a fissure usually proceeds forward and outward, and, in this manner becomes apparent both at the upper and the lower face of the palatine process. Here, particularly, the fissure is longest and broadest, and goes towards the space situated betweentheouter incisorand thecanine tooth. Itrarelybifurcates at its inferior face, presenting an inner which is smaller, between the two incisor teeth. Sometimes, also, a small process is detached which goes backward. The fissure, visible at the inferior face, is the mtem ma.rillarij suture [suhira intermaxilla^'is).

One or more furrows proceed from the posterior edge from behind forward, to the inferior face.

§ 583. The alveolar p^'oeess [processus alveolmds), is a prolongation of the anterior and external face of the body ; it is convex outward and concave inward, forming a considerable edge, and contains cavities for the teeth called the alveolar cavities [alveoli), which are, separated by thin osseous partitions. The alveoli are known externally by the projections, and the intermediate partitions, by the depressions which correspond to them.

§ 584. 'I'he malar o\' jugal pi'oeess [jj7'ocessus malaris s.jiigalis), is very short. It comprises only the broad rough surface, by which the posterior, superior, and anterior faces of the body are united. A portion

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of the bony partition of the maxillary sinus is often deficient in this region.

§ 585. The upper maxillary bones articulate, 1st, on the' median line, with each other, by the internal face of the palatine portion ; 2d, with the frontal bone (§ 568), by tile upper extremity of the nasal process ; 3d, with the external edge of the proper nasal bones, by their anterior edge ; 4th, with the unguiform bones, by their posterior edge and the anterior extremity of the internal edge of the upper face of their body ; 5th, with the ethmoid bone (§ 574), by this same edge, and by the crest of the ethmoid bone ; 6th, with the jalate bones, b_y the posterior extremity of this edge, the posterior part'ofThe posterior and internal face of the body, and the posterior edge of the palatine portion ; 7th, with the inferior turbinated bone, by the inferior turbinated spine ; 8th, with the vomer, by the palatine process.

§ 586. According to Portal, the upper maxillary bone is developed by several points of ossification, — two for the body, one below the infraorbital foramen, and another in the floor of the orbit ; a third in the nasal process, and two or three in the palatine process.

In several fetuses of three months, we have found it composed of three pieces ; of these, the anterior comprises the portion of the palatine and alveolar processes situated before the palatine duct, with the nasal process ; the middle, the body and the central part of the palatine process ; finally, the third placed externally, the posterior part of this same process. The palatine canal, which is still only a simple hole, the incisive ox anterior palatine foramen [foramen incisivtan s. j>alaiinwn anterius), appears enormous. The inner, the upper, and the posterior walls of the body are not yet formed. Then, the anterior portion is separated from the posterior, and a real intermaxillary bone exists, — a curious analogy with what is normally observed in almost all the animals inferior to man. Even when the two segments are not more entirely distinct, in the full grown fetus and afterwards, the line of. separation extends much farther, both in breadth and in length, across the palatine portion, so that it traverses all the breadth of the upper face. It often happens that it does not stop there, but is reflected upward, and insulates a part from the internal face of the body as an internal tliin layer, which is only applied against the external part. Farther, a branch of this upper fissure goes inward, and passes, behind the lachrymal channel, through the antrum Highmorianum, to the posterior face of the body, where it unites with the infra-orbital in the infra-orbital canal. We also find some slight traces of this arrangement in the adult ; it deserves to be remenked, as indicating, even in man, that the portion of the upper maxillary bone, in which the incisor teeth are situated, is separated from the others during the early periods of life, and then forms a real intermaxillary bone [os incisivum, intcrmaxillare)^ We always find in the young fetus the internal branch of the fissure on the under face of the palatine portion (§ 582), and this observation, together with the instances of division of the upper maxillary bone in the full groivn fetus, ( 1 ) seems to prove the primitive existence of a special piece of bone for each incisor tooth.

The maxillary sinus is already ver}'^ large in the full grown fetus, but does not extend so much outwardly.

Considered generally, the maxillary bone in the child, particularly Its alveolar portion, is much longer and broader in proportion to its height, than in the adult.

§ 587. The anomalies of this bon.e are, the non-development of the maxillary sinus, and the shortness of its palatine process, which leaves a greater or less interval on the median line between the maxillary bones, and whence generally results (at least when the division extends to the anterior extremity, or occupies the anterior part of the length of the upper jaws) the insulation of the anterior portion which supports the incisores, or of the intermaxillary bone. On the other hand, it sometimes happens also that the palatine process is prolonged posteriorly to a great extent, and even forms the posterior spine.

II. OF THE PALATE BONES.

§ 588. The 'palate bones {ossa j^alati) should be regarded as the posterior appendages of the upper maxillary bone. They correspond, from behind forward, to the intermaxillary portion of the upper, jaw.

They are thin layers curved on themselves, the upper larger and perpendicular part of which corresponds to the inner wall of the body of the upper maxillary bone, and the horizontal to the palatine process of this same bone, of which they are the continuation and the termination.

§ 589. The internal face of the horizontal portion presents two parallel eminences, separated very much from one another, which extend from the posterior to the anterior edge, and are called the upper and loiver turbinated crests, or the transverse eminences {crista turbinalis superior et inferior, s. line.ee. emmentes transversal). The external face is concave in the points corresponding to these two eminences, smooth in its anterior portion which is the most extensive, and hollowed posteriorly, by one or two longitudinal furrows, called the pterygo palatine fossce {sulci pterygo-palatini), which are continuous with the furrow of the palatine face of the upper maxillary bone.

The rough posterior edge presents downward, backward and outward, where the perpendicular part unites to the horizontal portion, a thick eminence called the pyramidal or pterygoid process {processus pyramidalis s. pterygoideus). The anterior edge is thin, uneven, and extends below the inferior transverse line, in a small projection called the nasal process {processus nasalis). Above, the perpendicular portion divides into two eminences, the anterior called the orbital process (processus orbitalis), and the posterior the sphenoidal process (processus sphenoidalis) .

The first is deeply concave inward, convex upward, backward and outward, straight forward, downward and outward, rough externally, and smooth in all other parts of its surface.

The sphenoidal process is lower than the orbital, a continuation of the posterior edge of the palate bone upward : it is directed toward the posterior part of the orbital process, but rarely meets it.

The space which remains between these two processes, and which is always filled by the dura mater in the recent state, constitutes the spheno -‘palatine foramen {foramen spheno-palatinum).

The* horizontal portion is terminated forward bj'- a sharp, rough and thin edge ; inward by a broad and uneven edge ; backward by a smooth edge. -The last is notched, and terminates internally by a pointed eminence.

§ 590. The palate bones articulate, 1st, with each other by their horizontal portions. The union of the internal eminences of their posterior edges gives origin to the nasal or the posterior joalatine spine {spma palatina posterior) ; 2d,' with the upper maxillary bones (§ 585) ; the anterior part of their perpendicular portion contracts the orifice of the antrum Highmorianum ; the anterior part of the external face of this portion applies itself to that of the thin wall of the maxillary sinus found behind its orifice ; the posterior remains a little distance from it, producing the pterygo-palatine canal {canalis pterygo-palatinus) between it and the edge of the posterior face of the maxillary bone ; 3d, with the ethmoid bone, by the orbital process, so that the internal and concave face of this process covers and enlarges the posterior ethmoid cells, and the posterior extremity of the middle turbinated bone meets the upper process of its internal face ; 4th, with the sphenoid bone ; for the posterior edge of the perpendicular portion embraces the anterior face of the pterygoid processes, the pyramidal process insinuates itself between the two wings of these last, and the posterior face of the orbital processes applies itself to the anterior of the body : the horns of the sphenoid bone frequently make part of the palate bones, and are only an enlargement of the posterior face of the palatine process ; the bone, wedged in between the pterygoid process of the sphenoid bone and the body of the superior maxillary bone, forms or completes with it the pterygo-palatine fossa ( F. pterygo-palatina) ; 5th, with the posterior extremity of the lower turbinated bone, by the lower transverse eminence ; 6th, finally, with the posterior extremity of the lower edge of the vomer, by the palatine crest.

§ 591. At first, the palate bone is situated very low, so that its perpendicular portion is shorter than its horizontal portion, and considerably large, particularly from before backward, in proportion to its other dimensions. We have found it in the fetus of three months, composed of a single nucleus of bone, which appeared as a curved plate.

§ 592. The anomalies it offers consist in the separation of the two palatine portions, existing either alone or attended with a similar division of the upper maxillary bones. This anomaly seems to be

436

DESCniI'ïlVE anatomy.

sometimes although rarely occasioned, and sometimes compensated for, by the extension of the palatine process of the maxillary bones backward, which is extremely remarkable.

III. or THE MALAR BONES.

§ 593. The malar or the cheek bones (ossa jugaUa, zijgomatica, malaria^ malae) have an irregular quadrilateral form ; they are coiivex externally and concave internally. They, are composed of two pieces united at a right angle, the upper, smaller and internal; th^ lower, larger, perpendicular and external. The first is very much grooved upward and forward, and forms the anterior part of the .anterior wall of the orbit. The second is situated outwardly under the skin of the cheeks, and forms, by its projection, the broadest region of the face.

§ 594. The zygomaiic canal (cunalis zygomaiicus), which is generally single, sometimes double, or even multiple, passes through the malar bone. This canal commences by an upper orifice at the anterior face of the superior portion, and terminates, on one side, at the external face of the perpendicular portion, by the external zygomatic foramen ( foramen zygomaticuin externum) ; on the other, at the internal face of this same part, by another opening, called the internal zygomatic foramen ( foramen zygomaticum internum).

§ 595, This bone articulates, 1st, with the malar process of the upper maxillary bone, by the anterior edge of its external portion, also by the internal edge of its superior portion, between which is a rough surface ; 2d, by the posterior part of the inner rough edge of its horizontal face, with the edge formed outward by the union of the anterior and external faces of the large wing of the sphenoid bone ; 3d, by its upper portion with the malar process of the frontal bone ; 4th, by its inferior and posterior parts with the zygomatic process of the temporal bone. We call those prolongations by which this bone articulates with the sphenoid bone, the upper maxillary bone and the temporal bone, the sphenoidal, the maxillary, and the temporal processes.

The greater part of its posterior edge is free.

The articulation of this bone with the temporal bone forms a bridge (zygoma, jugum) above the temporal fossa (fossa temporalis) comprised between the anterior part of the- squamous portion, the large wing of the sphenoid bone and the posterior face of the malar bone ; this bridge varies in form, according to the races.

§ 596. The malar bone appears early, toward the commencement of the third month. We have always found it composed of a single nucleus of bone. The numerous observations and facts on this subject carefully collected, would lead us to doubt the assertion of Portal, that there are three points of ossification.

§ 597. This bone is sometimes entirely deficient ;(1) a striking resemblance with what is seen in several mammalia, as the tanrec, the

(1) Meckel, Bcytrage, vol. i. p. ii. p. 54. — Dumeril, Bull, de la soc. phil. vol. iii.

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sloth, and the ant-eater. It is sometimes divided by a suture into two portions, an anterior and a posterior,(l) or even into three pieces. (2)

IV. OF THE NASAL BONES.

§ 598. The «asa7 bones {ossa nasi, nasalia, nasi propria) are small bones, of an oblong square form, thick at their upper part, thinner and broader downward, which form the upper and anterior walls of the bony frame of the nose. They are situated obliquely from above downward and from behind forward, between the frontal bone, the maxillary bone, and the perpendicular plate of the ethmoid bone. They describe a double curve, whence they are concave forward and convex backvmrd in their upper part, while in their lower part they are convex forward and concave backward. Near their centre, we observe one or more foramina which pass entirely through them.

§ 599. They articulate, 1st, with each other by a rough and very broad surface, which is usually extended into a crest or spine, called the nasal crest or spine {crista, s. spina nasalis) ; 2d, with the ethmoid bone, directly, by the nasàl spine, or indirectly, by a piece of bone interposed between them, which also represents a spine ; 3d, with the frontal bone (§ 568) by their upper and thickest edge; 4th, finally, with the anterior edge of the nasal process of the upper maxillary bone, by their outer edge.

§ 600. Each of them is developed by a single nucleus of bone which begins to appear at the commencement of the third month.

§ 601. Both bones not unfrequently unite in their whole length, or only at their upper part, which deserves to be remarked as offering an analogy with the formation of several simiæ.

« 

V. OF THE UNGUIFORM BONES.

§ 602. The unguiform or the lachrymal bones {ossa lachrymalia, s. unguis) are the smallest of the bones of the face. They are only thin plates of an oblong quadrangular form, situated in the inner angle of the eye between the maxillary, the frontal, and the ethmoid bones, and are frequently perforated.

Their outer face is divided by a longitudinal crest, to which a depression corresponds posteriorly, into two parts, an anterior and a posterior, the proportional extent of which varies much. The posterior part is sometimes very small, and then the papyraceous plate of the ethmoid bone is rather extensive. When, on the contrary, the anterior is narrower, it is made up by the greater breadth of the nasal process of the upper maxillary bone. The anterior part is always much thinner than the posterior, concave externally and convex internally. It forms the posterior wall of the nasal channel {sulcus canalis nasalis), the anterior of which belongs to the posterior part of the external face of the nasal process of the upper maxillary bone (§ 581).

(1) Sanclifort, Obs. anat. pathoL, b. iii. p. 113, iv. p. 134.

(2) Spix, Ccphalogenesis, p. 19.

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DESCRIPTIVE ANATOMT.

§ 603. The unguiform bone articulates, 1st, by its upper edge with the orbital portion of the frontal bone ; 2d, bj^ its posterior edge, with the anterior edge of the os planum ; 3d, dowinvard, by its inferior edge, with the anterior part of the inner edge of the body of thebipper maxillary bone ; 4th, forward, by its anterior edge, with the posterior edge of the nasal process of this bone. All these edges are thin and smooth. The posterior face of the unguiform bone closes the anterior ethmoidal cells.

§ 604. The ossification of the unguiform bone begins in the fifth or sixth month.

§ 605. The unguiform bone is not unfrequently extremely small or entirely deficient. ^It is then supplied by the cribriform plate of the ethmoid bone, or more frequently by the ascending branch of the upper maxillary bone, which becomes broader, or finally by both these at once.

VI. OF THE INFERIOR TURBINATED BONES.

§ 606. The inferior iurhinatecl bones (conchce, conchœ inferiores, ossa iurhinuta s. spongiosa), thus called to distinguish them from the superior and middle turbinated portions of the ethmoid bone, form a very great part of the base of the olfactory organ.

In form and structure they resemble the ethmoidal turbinated bones, but are larger than them, and are convex externally. They are elongated from before backward, higher in the centre than in the other parts, straight, very thin and smooth in their upper portion, bulging in the lov/er portion, and terminate downward by a rounded edge, which is reflected from below upward. Their inferior portion is rough, and on its external face are tubercles, and small blind depressions on its internal.

§ 607. Near the centre, the upper edge, which is sharp, is reflected outward and downward, to produce the broad unciform maxillary process {processus maxillaris), by which it is joined to the lower edge of the maxillary sinus. In front of this process we perceive another, which varies in length, — the nasal or lachrymal process (processus lachrymalis s. nasalis), the direction of which is from below upward ; it articulates with the -lower extremity of the unguiform bones. Between these two eminences, we sometimes see the ethmoidal processes (processus ethmoid ales'), which go to the large and small processes of the ethmoid bone (§ 574).

The anterior and blunter extremity of the bone articulates, 4th, with the lower transverse eminence of the upper maxillary bone (§ 585), and the posterior with the corresponding eminence of the palate bone (§ 590).

§ 608. Ossification appears first in the fifth month, at its centre, where there is only one nucleus. We have never found several.

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VII. OF THE VOMER.

§ 609. The ploughshare (vomer) is an irregularly quadrilateral bone, situated on the median line to which it imperfectly corresponds, and downward and backward divides the nasal cavity into two portions. Its upper edge, which is the thickest and also the shortest, is divided into two lateral processes, called the wings (alÅ“ vomeri), between which is a furrow. These wings embrace the spine of the sphenoid bo'ne, and are covered by the vaginal processes of this bone. The upper and anterior edge, the longest of all, is also cleft, but much thinner ; it is articulated posteriorly with the posterior edge of the perpendicular plate of the ethmoid bone, and forward with the inferior edge of the cartilaginous septum of the nasal fossæ. The inferior, which is the third in extent, articulates with the palatine crest (§ 585). The posterior is free. Thus the vomer articulates with the ethmoid bone, the sphenoid bone, the upper maxillary bones and the palate bones.

§ 610. In the fetus of four months, there is already formed only a single bone, which is much lower,%r proportion to its length, than in the adult, and is composed of two ÿates, of equal thickness in every part, separated in almost all their height, and united only at their lower part, loose around the cartilage of the septum of the nasal fossæ, and having the appearance of a single plate reflected on itself. It is then proportionally and absolutely much broader than in the adult. This form is found even in the full grown fetus, where the lateral plates are no where turned outwardly. We have never found several points of ossification, which Portal asserts exist.

§ 611. When the nose is not completely developed, the vomer is some times deficient, or is perforated by an opening.

VIII. OF THE LOWER BIAXILL.iRY RONE.

§ 612. The lower maxillary bone (maxilla, s. mandihida inferior, os muxillare inferius) is situated opposite the upper. It has a parabolical form, resembling a horse-shoe. We may, for the convenience of study, divide it into the central, alveolar, or horizontal portion (pars alveolaris, ramus horizontalis), and the articular, lateral or ascending parts (partes articular es, rami perpemliculares).

§ 613. These three parts are marked with muscular impressions, which render the surface uneven. In the centre of the anterior and posterior faces of the central portion are two longitudinal eminences, called the external and the internal mental crests (crista mentalis externa et interna). At some distance on this crest, equally on both faces, we perceive on each side a line, the direction of which is almost the same as that of the upper edge : these are called the external and internal oblique lines (linea obliqua externa et interna). This line extends from before backward, to the second small molar tooth.

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Below this same tooth, about the centre of the bone, is the mental or anterior maxillary foramen [foramen maxillare anticum, s. mentale).

§ 614. The ascending branch is divided upward into two processes, of which the anterior, called the coronoid 'process [processus coronoideus), is greater, thinner, and more elevated than the posterior, flattened from without inward, and pointeil. The second, called the condyloid procsss [processus condyloidtiis), is broader from one side to the other than from before backward. Its direction is a little oblique from without inward and from before backward, s'o that the the two articular surfaces converge toward each other backward. Its upper face is rounded, and usually divided, by a transverse line, into an anterior and a posterior part.

This process, which is the broadest part of the lower maxillary bone, is about six lines broad from one side to the other .; its height and thickness are about three lines. The thick and contracted part which comes after it is its neck. The sio-moid notch (incisiLra semilunaris, s. sis;moidea) is that part of the upper edge which is found between the two processes and the angle of the jaw [angulus maxillaris) is the place where the posterior and inferior edges are united with each' other. A little above the middle of the internal face is a large opening, the posterior maxillary foramen [foramen maxillare ‘posterius), which leads into the maxillary canal [canalis maxillaris). This last penetrates into the bone nearer its lower than its upper edge, opens externally by the « mental hole, but still continues as far as the median line, and furnishes, at its upper jiart, some small canals which go to the roots of the teeth. A small fissure proceeds from this posterior maxillary foramen along â–  the internal face, wdrich is called the myto-hyoid fissure [sulcus maxillÅ“ inferioris, s. mylo-hyoideus). Sometimes, but rarely, this fissure is converted into a real canal, either at its origin or in one or several ]iarts of its course ; more rarely still, it divides into two branches at the moment of its origin.

§ 615. The lower maxillary bone does not articulate, except with the temporal bones, on which it moves.

§616. We have found this bone formed, in the earliest periods, of but two lateral pieces, united on the median line by a cartilaginous substance. In fact, Autenreith pretends that it developes itself by three or four points of ossification, belonging to the condyle, to the coronoid process, to the horizontal portion, and to the angle.(l) Even before him, Kerkring said he had found the coronoid process at least, developed separately. (2) Very recently still, Spix(3) has admitted not only the osseous nuclei pointed out by Autenreith, but has also described and figured a fifth, a plate which closes the alveolar edge internally, and which, according to him, remains separate and distinct until the fourth month. But, however carefully we may have examined even the youngest fetuses, we have never found, either during or after pre (1) Wiedemann, Archiv f hr Zoologie und Zoolumie, vol. i, pt. i. p. 39.

(2) Opp. omn. anal. p. 233.

(3) Vcphalogenesis, p. 20.

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paration, more than a single plate in each portion of the lower maxillary bone. It is true that the alveolar edge is not closed at first internally by the osseous substance ; but there is no special nucleus of bone formed in this part : there is developed a process, the direction of which is from before backward, which becomes an anterior portion of the bone, and is at first separated from it by a small posterior fissure. When it has arrived at the region of the ascending branch, it unites to its internal face by a bridge, and forms the posterior maxillary foramen. In the commencement, the maxillary canal is not yet closed at its upper part, and is connected with the dental edge.

We always find, even in the full-grown fetus, two openings at least, in the place of the posterior maxillary foramen ; one much more ample, leads to a furrow which exists at the bottom of the posterior alveolar process, and Vhich ceases at its anterior extremity. The other, smaller and inferior, leads to a canal which passes under the alveolar process, and which goes to the internal extremity of the half of the jaw. The furrow and the canal communicate* by several openings, and all lead to the anterior maxillary foramen ; but the furrow more directly.

A pretended line of demarkation, pointed out by Spix, between the plate and the rest of the lower maxillary bone, is only the mylo-hyoid fissure (§ 614), which is extensive in the fetus, because of the great development of the mylo-hyoid branch of the fifth pair of nerves.

We shall speak of the development of the alveolar edge, when treating of the teeth.

The two lateral parts are straighter and nearer to each other, in proportion to the youth of the bone. The ascending branch, especially the articular process, is more depressed, so that the alveolar edge does not project in the fourth month of pregnancy. There is less difference between the direction of the posterior edge of the ascending branch, and the inferior edge of the horizontal portion ; and, also between the anterior edge of the first and the upper edge of the second; and, fourthly, the articular process is contracted from right to left.

In the full-grown fetus, the lower maxillary bone does not resemble the formation which distinguishes it in the adult, except in regard to the fourth condition. As to the first, the bone, in the early periods of the fetal state, differs more than the lower maxillary bone of the adult, since its form is then rounder. This, it is true, depends partly on the greater projection of the alveoli ; but this circumstance is not the only cause. The maxillary bone, however, is still much flattened at this period ; its edges are very round, and the whole bone is very broad. Finally, it is perfectly developed very early, since, in the fetus of three months even, it is the largest bone in the whole body.

The union of the two lateral portions commences in the first months after birth. Generally, however, in the course of the second year we observe always at the upper edge a small fissure, the direction of which is from above downward, whence the fusion takes place from below upward. This peculiarity is very remarkable, because the bones

VoL. I. 56

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DESCRIPTIVE ANATOMY.

situated below the lower maxillary bone, the sternum, and the hyoid bone, also often unite in the median line, while those found above it, the upper maxillary bone and the other accessory bones of the face, remain separate during life ; and the lower parts of the two pieces of the frontal bone are also the last in which this fusion takes place.

Sometimes the two portions are already united in the full-grown fetus ; this union, in certain cases, seems to take place_ at the expense of the formation of the other bones of the head.

Sometimes, also, there is developed between these two halves, either a single. bone or two small bones, a right and a left, which unite on the median line : not long since, we observed this anomaly in a child three months old ; or, this horizontal branch is divided still farther back into two large halves ; a striking analogy with the development of the upper maxillary bone, and with the constant arrangement of the lower maxillary bone in birds, in reptiles, and in the mammalia.

§ 617. The two portions of the inferior maxillary bone do not, to our knowledge, ever continue separated, although this arrangement exists, in the normal state, m many animals, and is a very frequent anomaly in the superior maxillary bone.

An unfrequent anomaly is the union of the articular process with the temporal bone. This prevents mastication (1).

IX. OF THE HYOID BONE.

§ 618. The hyoid bones or the hyoid bone {ossa hyoidca, s. os hy~ oides){2), forms an arch which is convex forward. It is situated behind and below the lower maxillary bone, at the root of the tongue and at the upper part of the neck. It is generally considered a single bone, and is divided into a central portion or body, and four hoftis, two on each side. But, as these parts remain distinct through life, it is better to admit five distinct hyoid bones,, a middle and four lateral bones.

I. OF THE CENTRAL HYOID BONE.

§ 619. The central hyoid bone, or the body {os hyoides medium, s. basis), the largest of all, is situated transversely.

Its anterior face is slightly convex, and the posterior very deeply grooved.

The anterior face is divided into a larger inferior ascending and uniformly convex portion, and a smaller superior portion which is also arched from right to left, but more or less grooved from above downward, which is also divided into two lateral portions by a small eminence between.

(1) Sandifort, Obs. Anat. Patlio. vol. 1, p. 102. tab. vi. vol. ii. p. 117.

(2) Sec, on the hyoid bone considered in all vertebrated animals, the memoir

on the anterior bones of the ciiest, by G. F. St. Hilaire, {Philosophie Anatmmquc, p. 139). Ho admits seven pieces in the hyoid bone of the mammalia, and refers to it alscj the styloid processes of the temporal bones. F. T.

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The upper and lower edges are sharp, the two lateral are somewhat broader.

At the end of the upper part of the anterior face, there is on each side a small plain articular surface covered with cartilage.

II. OF THE INFERIOR HYOID BONE.

§ 620. The inferior hyoid hone, called also the inferior horns, the large horns of the hyoid bone [ossa hyoidea lateratia inferiora, cornua inferiora, s. magna), is the direct continuation of the preceding, and forms the largest posterior part of a horizontal arch. Eaclr of the two pieces of which it is composed, is longer than the central hyoid hone, but it is much weaker. Their anterior part is the broadest. They then gradually contract, and terminate backward by a rounded bulging edge. These two pieces usually diverge from before backward, but they rarely incline a little toward each other posteriorly.

Their anterior broader edge is slightly concave and covered with cartilage. The inner end of the upper part of their anterior face ha.s also an articular facet, which is smooth and covered with cartilage.

They often, in the same subject, vary considerably in form and size on the different sides.

They articulate with the central piece by a fibro-cartilaginous mass, and sometimes unite in the later periods of hfe m one bone.

III. OF THE SUPERIOR HYOID BONE.

§ 621. The two pieces of the superior hyoid bone, called also the superior or small horns of the hyoidbone (ossa hyoidea,s.cormM superiora s. minima), have a more or less rounded and oblong form. They gradually grow thin from one extremity to the other ; are oblique from below upward, and from within outward ; and are situated in the place where the middle and inferior bones unite, being connected with them by a loose capsular ligament.

They are always very thin, and usually much shorter, but sometimes also much longer, than the inferior bones. Their length varies from two hires to an inch and a half In the latter case, it often but not always happens, that each is composed of two separate pieces.

Of all bones, these present the greatest differences in respect to form and length, not only in different individuals, but also hr both sides of the body in the same individual. We not unfrequently find them twice as long on one side as on the other, and this side is almost always the left, at least according to our observations. We have never found this to be the case on the right side, although we have examined many hyoid bones ( 1 ) .

§ 622. The hyoid bones articulate writh one another at the places pointed out (§ 619, 620, 621), and farther upward, with the styloid

(1) The remark, that this arrangement is constant, is more probable, because Duvernoy has made the same remark. — {Comm. Feirop., vob vii. p. 216.)

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process of the temporal bone, downward with the centre of the upper edge and the superior horns of the thyroid cartilage.

§ 623. They begin to ossify about the end of pregnancy, and sooner in the lower lateral hyoid bones than in the central bone. The upper lateral hyoid bones do not ossify till several months after birth.

§ 624.' These bones continue on the neck, the chain of bones formed in the head by the lower maxillary bone ; in the chest, by the ribs and sternum; in the pelvis, by the ^mphysis pubis. We may then consider them as corresponding to thlc ribs and sternum, and call the central part the bone of the wec/r, and the lateral parts the cervical ribs.

CHAPTER III.

GENERAL REMARKS ON THE BONES OF THE HEAD.

§ 625. The bones of the head (ossa capitis), taken collectively, may be considered, 1st, in regard to the general form of the whole, and the differences in respect to age, sexes, and races ; 2d, as regards the characteristics of certaiir parts of the head, to produce which, several bones concur, having regard principally to the relations between these parts and the other organic systems.

I. REMARKS ON THE GENERAL FORM OF THE HEAD.

§ 626. The head has, as a whole, a rounded form. This however is more evident in the skull than in the face ; for this last resembles, properly speaking, an irregular square, furnished however with numerous depressions and elevations, of which we see but slight traces, so long as the portions of the other organic systems which cover them are not removed. Further, the skull itself is not round and regular. Its anterior, superior, posterior, and lateral portions, are, it is true, plain and smooth, except a few inconsiderable asperities ; but its lower part, or the base {basis cranii), is extremely irregular, because of numerous muscular impressions, and large or small holes, through which pass vessels or nerves, of which we find but slight traces in its other regions.

The skull contains a cavity, generally inclosed with very thin walls, which is convex externally and concave internally in the different regions which have been mentioned. The internal face corresponds with tolerable exactness to the external. On the contrary, not only its lower part is not uniformly concave internally, and convex externally, but the external and internal faces do rrot correspond.

The general differences between the external and the internal faces of the skull depend on their relations with the organs with which both are connected.

1st. The greater part of the internal face, especially the anterior part of the base, presents numerous digital depressions and mammillary eminences (§ 526).

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2d. On the internal face of the lateral and superior parts, numerous fissures {sulci meningei) arise from the middle part of the base, in which are situated the cerebral arteries.

3d. This same face presents other fissures for the veins (sulci venosi), which are broader, and are situated in the upper part of the skull on the median line; and in the lower part, on both sides of this line, they are the traces of the sinuses of the dura mater.

4th. The internal wall of the base presents several depressions, which are the largest of any, and which correspond to the difierent divisions of the encephalon.

The elevations and projections which render the internal face uneven, serve partly for the attachment of the dura mater. Others circumscribe several of the depressions which we have mentioned ; and others still, as the petrous portion of the temporal bone, possess an independent existence.

§ 627. The form of the skull is not exactly round. If cut perpendicularly and horizontally, it represents ellipses, of which the greater diameter is backward, the smaller forward. The skull is much longer from before backward, thair from right to left and from above downward. The proportion between its greatest length from the glabella of the frontal bone to the spine of the occipital bone, its greatest breadth from the squamous portion of one temporal bone to that of the other, and its greatest height, is nearly : : 3.3 : 2.3.

If we examine the interior of the skull, we perceive that this cavity, uniform in parts, divides, especially downward, into three portions situated successively from before backward, the anterior^ the middle, and the posterior.

The anterior, which is the smallest in every dimension, occupies the most elevated region. Its sides are formed by the orbital portions of the frontal bone ; its centre by the central part of the ethmoid bone, and its posterior part by the small wings of the sphenoid bone. Forward, and on the sides, it is imperceptibly continuous by a rounded edge with the lateral faces of the skull ; while backward it is separated from its central part by a sharp and grooved edge. Its form is then almost semicircular. Downward, on both sides, where it forms the roof of the orbits, it is strongly bulging, and projects into the cavity of the skull, while it presents a considerable depression in almost all its central portion, which is formed forward principally by the cribriform plate of the ethmoid bone. The crista galli process (§ 571) arises from its centre; before this, the internal frontal crest arises (§ 564), between which and the process is the foramen cæcum (§ 566).

The anterior extremities of the anterior lobes of the cerebrum and the olfactory nerves, the threads of which pass through the holes of the cribriform plate, rest upon this portion. To the crista galli process and to the frontal ridge is attached the lower anterior extremity of the large falx of the dura mater.

The central portion, which deserves this name both from its situation and from its extent, has the form of a figure 8 placed trans

416 DESCr.îPTlVE ANATOMY.

versely ( oo ), for it is much narrower in the centre than on the two sides. It is formed by the body the large wings and the posterior and inferior portions of the small wings of the sphenoid bone, and by the squamous and the large anterior part of the temporal bones. Its anterior edge, formed by the small wings of the sphenoid bone, consists in two large lateral arches and a central arch which is smaller : the lateral is insensibly continuous with the lateral face of the cranium ; the posterior is composed of a central, smaller, and straight portion, the upper edge of the sloping part of the sphenoid bone, and of two much more extensive, sharp, and almost straight edges, which proceed from within outward and from before backward, the upper angles of the petrous portion of the temporal bone. This portion is grooved, but its central part, the sella turcica, is much more elevated than the lateral portions, which are more extensve than it.

In its centre is situated the pituitary gland, and on the two sides the anterior part of the posterior lobes of the brain.

The posterior portion, which is the largest of all, has an almost circular form. It is for the most part composed of the occipital portion of the basilar bone, forward and on the sides by a small part of the temporal and of the sphenoid bones. The posterior edge of the second portion separates it from the last forward. In every other direction it is gradually continuous with the other walls of the skull.

It lodges the cerebellum, the medulla oblongata, and the inferior part of the venous sinuses of the cerebrum. The anterior edge of the tentorium is attached to its anterior and sharp edge.

§ 628. The base of the skull, considered in regard to its external and its internal faces, ascends from its posterior to its anterior portion, which is the larger. The .first is formed by the posterior and inferior part of the squamous portion of the occipital bone. The occipital foramen is situated almost horizontally a little behind the centre. After leaving this point, the body of the sphenoid bone suddenly rises, then curves forward above the sella turcica : this last is almost horizontal. From thence the internal face of the base of the skull divides into an upper and inirer and an outer and lower portion. The first elevates itself again, but slightly, before the anterior edge of the sella turcica ; the second, which comprises the wings of the sphenoid bone and the lower part of the ethmoid bone, turns perpendicularly downward, to assist in forming the nasal fossæ.

§ 629. The facial portion of the head represents a very irregular square or triangle, which is much higher forward than backward, and is situated below the anterior half of the cranium, extending a little in front of it. Of the fourteen bones which compose it, thirteen are firmly united, either with each other or with the adjacent bones of the skull, by broad dentated surfaces, by sutures, or by smooth, sharp edges. One alone, the lower maxillary bone, is movably articulated with the temporal bones.

Instead of a single large cavity, like that of the skull, the bones of the face, form (not however alone, but with those of the skull) other

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and more open cavities and depressions, which are connected with the radiations of the nervous system the organs of sense, or with the movable organs of mastication.

The cavities of the first kind are situated forward ; those of the second are found on the side, and are farther backw'ard. The first are the cavities of the orbits, the nasal fossæ, and the cavity of the mouth ; the second are the temporal fossæ.

I. OF THE ORBITS.

§ 630. The orbits {orbitæ) have the form of truncated, short pyramids with unequal faces, of which the very broad and almost perpendicular base looks forward, and is directed a little from before backward and from within outward, while the summit corresponds to the posterior extremity. Both orbits converge very much backward, so that they are for the most part, if not entirely, turned forward and a little outward.

The outer and lower faces are straight. The internal and the upper, especially the latter, on the contrary, are very concave.

The upper face, called the vault of the orbit {lacunar orbitæ), is formed, in most of its anterior part, by the orbitar portion of the frontal bone. We observe, in a small part of its posterior portion, the inferior face of the small wing of the sphenoid bone. It is insensibly continuous, by a rounded edge, with the internal and the external wmlls of the orbits.

The external wall in the direction of length is oblique from without inward and from before backward, in that of height it is directed from without inward and from above downward, and its length exceeds its height very much. Its anterior and smaller part is formed by the malar bone, and the posterior and largèr portion by the large wnng of the sphenoid bone ; it is separated backward and upward from the upper by the superior sphenoid fissure, backward and downward by the inferior sphenoid fissure.

The lower face is irregularly triangular, and mostly formed by the upper face of the body of the upper maxillary bone, forward by the malar bone, and inward by the orbital portion of the palate bone. It descends a little from behind forward and from within outward.

The inner face is formed at its central part, which is the most extensive, by the lateral plate of the ethmoid bone, forward by the lacrymal bone, and backward in a small portion by the body of the sphenoid bone. Its direction is a little from before backward and from within outward, and it descends obliquely downward and outward.

The nasal canal commences at its anterior extremity.

The anterior opening of the cavity of the orbit is almost quadrilateral ; its breadth however exceeds its height, and it is circumscribed by rounded, grooved edges, which are insensibly continuous with each other.

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This cavity is connected with the cavUy of ihc skull, with the nasal cavity, with the ‘pterygoid fossa, and with the anterior part of the face.

1st. With the cavity of the skidl, by the optic foiamen, which is found at its posterior extremity, always a hltle within its axis (§ 541) ; more anteriorly, by the superior sphenoid fissure (§ 541) ; forward, by the anterior and posterior ethmoid foramina {foramina ethmoidalia anleriora et postcriora), situated between the orbital part of the frontal bone and the upper edge of the os planum of the ethmoid bone,

2d. With the nasal fossa, by the anterior ethmoid foramina and the nasal canal.

3d. With the pterygoid fossa, by the inferior sphenoidal fissure.

4th. With the anterior part of the face, by its large anterior opening, the infra-orbital canal, and the foramina of the malar bone.

§ G31. Seven bones concur in its formation, viz. the frontal bone, the sphenoid bone, the upper maxillary bone, the malar bone, the palate bone, the ethmoid bone, and the unguiform bone.

§ 632. In youth the orbits are proportionally deeper, and their walls are more concave ; the internal, which does not even exist in the fetus, is much lower ; the inferior is concave and almost straight, or less oblique from above downward and from behind forward ; finally, the anterior opening is more or less transversely elongated. Considered as a whole, the breadth of the orbital fossa exceeds its height very much. Its external edge, formed in a great part by the malar bone, projects very much from above downward and from behind forward, while afterward it descends almost perpendicularly. These remarkable differences are greater in proportion as the fetus is younger. They depend on the fact that the face is at first low, and lengthens gradually.

II. OF THE NASAL FOSSÆ.

§ 633. The lias«/ fossa {cavium nasi, nares internÅ“){l) is situated below and between the two cavities of the orbits (§ 624 — 629) ; but it extends also above them, by some of its prolongations. It has a very irregular form ; it is however on the whole quadrangular, and similar to the form of the face. A perpendicvlar septum {septum narium), directed from before backward, divides it in its broadest part into two halves, a right and a left. We may divide it into the proper nasal fossa, and into secondary or accessory cavities.

§ 634. In (he proper nasal fossa we distinguish an anterior and a posterior opening, the floor, the upper wall or the vault, and the lateral walls. The accessory cavities comprehend the three nasal sinuses.

The anterior opening {aperlura narium anterior, s. faciei pyriformis) is elongated and pyriform. It terminates in a point at its iqrper part, enlarges downward, but again contracts toward its inferior extremity. It is single, because the bony septum does not extend entirely forward. The lines which circumscribe it arc always arched externally. It is

(1) Ziervogcl, Diss. de narihws internis, Upeal, 176Ü.

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not exactly perpendicular, but, regarded from above downward, it projects a little backward. At its lower part, it projects a little from without inward, and from behind forward, and in the middle of the inferior edge we see the anterior nasal spine {spina nasalis anterior). It is formed above by the inferior edge of the nasal bones, and in almost all its lower part by the nasal process and the body of the upper maxillary bone.

The posterior aperture [apertura nasalis posterior) is lower^ but much broader than the anterior. It represents a somewhat regular square, and is always double, because the septum, which terminates by an oblique and serrated edge, extends to the posterior extremity of the nasal fossa. It is formed by the inner plate of the pterygoid processes of the sphenoid bone, the vomer, and the horizontal portion of the palate bone.

The floor of the nasal fossa is almost straight, and slightly conca\"e, for it is a little elevated on each side, internally and externally, toward the septum and the lateral walls. It terminates forward in a triangular edge, and backward in another edge semicircular on both sides, having two deep notches. We observe in the centre of the first the anterior nasal spine, and in the ceijti-e of the second the posterior nasal spine. The floor is formed by thè horizontal part of the upper maxillary and palate bones.

The upper wall, which is the smallest, is formed upward by the cribriform plate of the ethmoid bone, downward by the frontal bone and the nasal bones.

The posterior wall exists only at the summit of the nasal fossa, and is formed by the sphenoid bone.

The lateral walls of the nasal cavity are very irregular. They elevate themselves in an almost straight direction, but generally are a little convex externally, and present on their internal portion considerable projections, which render the surface very uneven, and also openings which lead into the accessory cavities.

The dh'ection of the eminences projecting internally is from before backward. They are convex internally, concave externally, and are situated one above the other. Their upper edges are attached, and their lower edges are free. We usually count three ; 1st, the rqjper ; 2d, the middle turbinated portion of the ethmoid hone (§ 572) ; 3d, the mferior turbhiated bone (§ 606). We usually remark, besides, a smaller process, situated at the rqjper and posterior part, — the upper turbinated portion of the ethmoid bone.

The depressions or semi-canals between these projections, which are directed from before backward, and always ascend from behind forward, are the superior the middle., and the inferior meatuses of the nose,which extend equal distances backward, but not forward.

Tire superior meatus is generally found between the upper and the middle turbiilated bones. It is the least elevated, the narrowest, and the shortest, for it does not project forward nearly as far as the two others. The sphenoidal sinuses open into its posterior part ; the cel VoL. I. 57

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Iules of the ethmoid bone, of the palate bone, and of the upper maxillary bone, in its central pari.

The middle meatus is much higher, and is the most uniform of the three in its height. It extends between the middle and the inferior turbinated bones, projects much farther forward than the upper, and receives in its anterior portion the frontal sinuses, and in its centre the maxillary sinuses.

The inferior meatus, the longest of all, is higher in its anterior part, but much lower in its posterior part than the middle meatus, and is situated between the inferior turbinated bone and the floor of the nasal cavity. It communicates with no accessory cavity ; the lachrymal duct, however, opens in its anterior extremity.

Besides these three channels, we always remark a fourth longitudinal depression, between the superior turbinated bone and the whole internal wall of the labyrinth and of the cribriform plate ; this depression extends much farther forward than the superior meatus. Finally, we usually discover a fifth, which is much smaller, the most superficial and the shortest of all, between the most superior and the upper turbinated portions of the ethmoid bone.

§ 635. The nasal fossa sends upward, oif the two sides and backward severed processes, prolongations, OÏ accessory cavities {sinus, antra).

1st. The upper prolongations are the frontal sinuses (§ 564), which open into the middle meatus by an orifice, which gradually narrows, and the direction of which is from before backward and from above downward.

2d. The lateral prolongations are the maxillary sinuses (§ 534), the largest ; they open by a very narrow orifice, in about the centre of the middle meatus.

3d. The posterior are the sphenoidal smuses (§ 536), which also open by a narrow orifice into the posterior part of the superior meatus.

§ 636. The nasal cavities communicate upward with the orbits and the cavity of the skull by the orbital holes, and with the cranium by openings in the cribriform plate ; backward, with the pharynx, by their posterior openings ; forward, with the cartilaginous nasal fossæ, by their anterior openings ; downward, with the oral cavity, by the anterior palatine foramen.

§ 637. They are formed by nine different bones ; 1st, the upper maxillary bones ; 2d, the palate bones ; 3d, the sphenoid bone ; 4th, the ethmoid bone ; 5th, the inferior turbinated bone ; 6th, the vomer ; 7th, the nasal bones ; 8th, the unguiform bones; and 9th, the frontal bone. Of all these, the upper maxillary bones contribute the most to their formation, as they form most of the floor and of the lateral walls. The ethmoid bone belongs to them entirely, forming their upper wall. The palate bones complete their floor, and contribute to fomi their lateral walls. The unguiform bones form part of their lateral walls, as does also the inferior turbinated bone. The sphenoid bone concurs to form the posterior part of the posterior wall and the lateral walls, by its pterygoid })roccsscs and its sinuses. The frontal bone and the nasal bones

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terminate their upper wall forward. Finally, the vomer forms the inferior and posterior part of the septum of the nose, while its upper wall is composed of the perpendicular plate of the ethmoid bone and of the spine of the sphenoid bone.

§ 638. The nasal fossas are much less spacious, proportionally speaking, in the early periods of life. From the smallness of the whole face, they are much lower and narrower, so that their anterior and posterior openings are proportionally much broader and lower; for the height of the posterior is one half greater than its breadth, the anterior in the-full grown fetus is not more than one half as broad as it is high, and its shape is not pyriform, but irregularly quadrilateral ; and again, the ethmoid cellules and the accessory cavities are not entirely develo]3ed at first, but acquire their normal size only at puberty.

In the early periods of life, and at the commencement of the third month of fetal existence, the nasal fossae are not entirely separated from the oral cavity at their lower part, for the floor gradually develops itself from without inward.

in. OP THE OEAL CAVITY.

§ 639. The bony oral cavity is a parabolic space, convex forward, terminated posteriorly by a straight edge, and situated below the nasal fossæ, from which it is separated by their floor (§ 631). The lower face of this last forms wdrat is called its roof or the bo7iy palate {palatum osseum, s: stabile), which is slightly concave and almost quadrangular. The anterior and lateral parts of the walls of the oral cavity, which are insensibly continuous with it, are formed upward by the alveolar edge of the upper maxillary bone, a small part of their posterior portion by the broader extremity of the pterygoid processes, and downward, by the whole inferior maxillary bone. A posterior and inferior wall does not exist, so that the bony cavity of the mouth is entirely open in this direction. The lateral walls are separated by a large hollow, which divides them into an upper and a lower part ; for the lower maxillary bone is not i.inited to the other bones of the head, but is movably articulated with the temporal bone (§ 633, 615), so that the oral cavity may open and close at different degrees in front, and it may vary considerably in height in all its extent. This peculiarity distinguishes it from all the other cavities of the head.

§ 640. This cavity is formed by four bones, the upper and lower maxillary bones, the palate bone, and the sphenoid bone. It is connected posteriorly with the pharynx, anteriorly with the anterior part of the face, by the mouth ; finally upward with the nasal fossæ, by the anterior palatine foramen, and with the pterygoid fossa by the posterior.

§ 641. Like the nasal fossæ it is lower the younger the subject is, as the teeth are not yet developed, and from the shortness of the ascending process of the upper maxillary bone it is proportionally shorter and broader.

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IV. OF TUE TEMPOBAI, FOSSA.

§ 642, The temporal Jossa (fossa temporalis^ ju^alis, zygomalicajis, the inferior and anterior somewhat contracted part of the lateral surface of the skull and the face.

It is open on all parts upward, backward, and downward, and also outward in most of its extent, and even on this point it is but imperfectly closed near the centre of its height by an almost transverse eminence, the direction of which is from before backward and slightly arched outward, which passes over it like a bridge. This is the zygomatic arch (zygoma, arcus zygomaticus, jugalis) which extends from the temporal bone to the face, or, to speak more precisely, to the upper maxillary bone.

It is much flatter at its upper than at its lower part, where it is depressed inward. Its internal wall descends at first a little obliquely from without inward, but in its lower portion it is perpendicular. The anterior is almost straight and very slightly grooved. The zygomatic arch anteriorly is broader than it is posteriorly.

§ 643. The temporal fossa is formed from four bones, viz. 1st, the sphenoid bone ; 2d, the temporal bone ; 3d, the upper maxillary bone ; and 4th, the malar bone. The larger and under wing of the sphenoid bone constitutes almost all of its inner wall : the upper and posterior part, which is less extensive than the rest, is formed from the anterior part of the squamous portion of the temporal bone. The zygomatic arch is formed by the zygomatic process of the temporal bone, and by the malar bone. This last and the upper maxillary bone form the anterior wall of the fossa.

§ 644, The temporal fossa communicates with the orbit by the inferior sphenoidal fissure, with the pterygoid fossa by the pterygo-palatine channel, and with the oral cavity by the posterior palatine foramen.

§ 645. The temporal fossa, from the greater breadth of the skull and the lowness of the fhce in the early periods of life, is much lower, planer, and narrower from above downward and from within outward, but longer on the contrary from before backward than in the adult.

II, COMPARISON OP THE BONES OF THE HEAD WITH EACH OTHER, AND WITH THE OTHER BONES.

§ 646. The bones of the head differ very much from each other, and from the other bones of the body, in regard to their forms ; there are however great traits of analogy between them and the latter. Certain bones of the skull, considered separately, or several together, more or less evidently resemble the veitebræ.(l)

(1) J. P. Prank first recotrnized the analog-y between the skull and the vertebrîo (Sammlung auserlesener Abhandlungen, vol. xv. p. 267; Epit. de curandis horn, morbis, b. ii. p. 42) ; he deduced it from the I'elation between the brain and the spinal marrow. Burdin (Cours d'études médicales, Paris, 1803, vol. i. p. 16) also thought that the head is only a vertebra more complicated than the others. This was also the

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We must regard the occipital portion of the basilar bone considered as one bone, the sphenoid portion united to the frontal bone, and the two temporal bones taken collectively with the parietal bones, as forming three systems, each corresponding to a vertebra, so that the skull is composed very evidently of three vertebræ, placed one after another from behind forward. It is easy to demonstrate the justice of

opinion of Keilmeyer (A. L. Ulrich, Annotationes quÅ“dam de sensu ac significatione ossium capitis, Berlin, 1816, p. 4). But as J. F. St. Hilaire remarks it was necessary to have had as clear an idea of this analogy as we now possess to discover it in the midst of a scries of foreign ideas, among which it was thrown as if by accident. Duméril has developed this idea still farther ( Considerations générales sur l'analogie qui existe entre tous les os et les muscles du tronc dans les animaux ; in the Magasin Encyclopédique, 1808, vol. iii). Having attended to the articular surfaces to which the muscles of ihe spine were attached in man and the mammalia, he thought he could perceive that the posterior parts of their skull presented eminences, processes, depressions, and cavities like the posterior parts of t!ie vertebræ, whence he concluded, in his public essay, that the head is a vertebra immense in its dimensions. He established that the occipital hole corresponds to the spinal canal, of which it ia the origin ; that the basilar process, and very often the body of the sphenoid bone, correspond, in their structure and uses, to the bodies of the vertebræ ; that the condyles represent their articular facets ; that the occipital protuberance and the spaces below it are analogous to the spinous processes and their bony plates; finally, that the mastoid processes are exactly like the transverse processes. Thus Duméril presented his theory of analogies ; but the éxact resemblance which he had perceived was scarcely remarked or at least appeared but trifling, doubtless because it did not coincide with the exact and consequently too confined meaning attached to the word vertebra. At the same time, the German anatomists were led to the samâ views by comparative anatomy. The celebrated Goethe conceived the idea that the head contained several vertebræ {Zur Xaturwissenschaft, vol. i. p. 250); he admitted six of them, three of which, the occipital, the anterior and the posterior sphenoid vertebræ envelop the brain, and the other three, the palatine, the superior maxillary, and the intermaxillary vertebræ, comprise that portion of the face in which the organs of sense are situated. Oken ( Ueber die Bedeutung der Schädelknochen, Jéna, 1817) admits three cephalic vertebræ, the auricular, composed of the occipital bone, to which is attached the petrous portion of the temporal bone, the styloid process of which corresponds to the sacrum, and the hyoid, which represents the pelvis ; the maxillary, of which the posterior sphenoid forms the body and also the transverse and oblique processes, and the parietal bones the spinous process, which also represents the upper and lower extremities, since the squamous portion stands in the place of the scapula and the iliac bone, the pterygoid i rocess, of the clavicle, the malar bone, -of the arm and the fore-arm, the upper maxillary bone, of the hand and fingers, the inter-maxillary bone, of the thumb, the maxillary condyle, of the femur, the coronoid process, of the leg, and the anterior part of the bone, of the foot. The ocular, composed of the anterior sphenoid ; its spinous process is the frontal bone ; while the vomer, the ethmoid bone, the inferior turbinated bones, the palate bones, and the nasal bones unite to represent the thorax. These ideas have been brought forward and modified by Oken (/s-ts, 1820, No. 6, p. 552; Esquisse d'un système d' anatbmie, de physiologie et d'kistoire naturelle, Paris, 1821, p. 41). lu this last treatise the author increases the number of the cephalic vertebræ to four, viz. 1st, the auricular vertebra, which has for its body the basilar process, for transverse processes the lateral occipital, and for a spinous process the upper occipital process ; 2d, the lingual vertebra, having for a body the posterior sphenoid, and for a spinous process the parietal bones ; 3d, the ocular vertebra, having for a body the anterior sphenoid, for transverse processes the small wings of the sphenoid bone, bone, and for a spinous process the frontal bone ; 4th, the nasal vertebra, having for a body the vomer, for transverse processes the ethmoid bone, and for a spinous process the nasal bones. According to him, the extremities may also be traced in the head, to wit, the arms in the upper maxillary bones, and the feet in the lower maxillary bone. All these views have been adopted and the last especially fully developed by J. B. Spix {Cephalogenesis, seu capitis ossei structura, formetio et significatio per omnes animalium classes, familias, genera et Å“tates digesta, Munich, 1815). Spix, not content with calling the cranium a prolongation of the vertebral system, con

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this analogy in regarding the forms, the mode of development, and the functions of these pieces of hones.

1st. The analogy is no where more evident than in the occipital portion of the basilar bone. This bone forms, like every vertebra, a ring, of which the central part is thick and spungy, while the lateral

eiders it a second formation representing all its parts, so that according to him, the being is formed by two complete sections, the one anterior and re.strained in its development, the head; the other posterior, and nninterruptcdly developed, the trunk: and as tlic latter has its extremities, the limbs, so the skull has similar extremities, the component parts of the face. Farther, he admits but three cephalic vcrtebiæ, called the occipital, the parietal, and the frontal vertebræ, fioin the parts which predominate, or the cranial, the thoracic, and the abdominal vertebræ, from the parts of the trunk to which lie supposes they correspond, or finally, the anterior, the central, and the posterior vertebræ, also from the analogies which he admits between tlic different parts of the licad and trunk; so that reserving the face, ho avails himself of three corresponding sections, the anterior, the central, and tho posterior, to form the appendages or the extremities of the cephalic portion of the animal. According to him the first cephalic vertebra, the occipital, presents all the parts of tho pelvis in the temporal bones; and all those of the inferior limbs in the lower maxillary bone ; the squamous portion of the temporal bone is the ilium, tho small bones of the car arc the pubis, and the ring of the tympanum is the ischium ; the maxillary condyle corresponds to the femur, the coronoid process to the tibia, tlic aiwlc to the fibula, the tubercle -above the posterior dental canal to the tarsu.s, the internal oblique line to the metatarsus, tlie alveolar process to the phedanges, and the teeth to the nails. In the second cephalic vertebra, the nasal bone corresponds to the sternum, the malar bone to the scapula and to the clavicle, and the upper maxillary bone contains all the parts of the upper extremity; finally, in the third, the ctlunuid bone represents the cricoid cartilage, the unguiform bone tho thyro'id cartilage, tlic palate hone and the internal wing of the pterygoid process the hyoid bone. Ãœlricli (Loc. cit.) continues these researches, but does not compare the jaws except to the upper 1 iinbs, and does not trace the inferior extremities in the head.

Cuvier (Régne animal, vol. i. p. 73) adopts the principle of the analogy between the head and the spine, neglecting always the term vertebræ, and admitting but three vertebræ, or, to use lii.s own expression, rings (ceintures), of the skull, the anterior of which is formed by the two frontal bones and the ethmoid bone, the central by the parietal bones and the splicnoid bone, the posterior hy the occipital bone. Blaiiiville also recognizes this principle of a.m\\ogy (Bulletin de Za soc. jji/iiZ., 1816, p. Ill, and 1817), and declares himself in favor even of the accessory comparisons established by £>kon and Kpix, at least as far as wc can judge from the vague manner in whicli lie expresses himself. Carus gave a new support to the doctrine of the three cranial vertebræ, ' y dividing the brain itself into three distinct portions and endeavoring to de'ermine the bones belonging to each of them in the vcrtcbrated animals. Ills work also is one of the most extensive wiiich has been published on tills sulijcrt (Lehrbuch der Zootomie, Leipsic, 1818, p. 164). Meckel (Beytrac'c zur vergleichenden Anatomie, vol. ii. p. 74-82), proposes to consider the whole sphenoid bone as a second vertebra, to make the third in the ethmoid bone and the frontal bone and to regard the temporal bone as a vertebra cut in two. Schultz (Be primordiis syslcmalis ossium et de evolutione epinæ dorsiin animalibus. Hallo, 1818 p 13) refuses to admit any analogy between the bones of the face and the vertebræ ' lîoianus (Isis, 1818, p. oOl ; 1819, p. 1364), admits four cephalic vertebræ, the first o'r the auricular, the secbiid or the gustative, the third or tlie oci//ar, and the fourth or tho olfactory, the body of which he formed in the vomer, tlie axis m the ethmoid bonc,‘and the spinous process in the nasal bones. At the same time, he considers the hyoid bones as the ribs of the first, the pterygoid processes as t hose of the second the external wings of these same processes as those of the third, and the bones of the palate as those of tlic fourth. Finally, he traces the upper extremities in the mastoid, the tympanal, the squamous, the malar, and the upper maxillary bones, and the lower extremities in the lower jaw. Burdach ( Vierter Bericht von der anatomischen Anstalt zu KÅ“nigsberg, Leipsic, 1821) endeavors to prove there are but three cephalic vertehrÅ“, and that the other bones ol the liead are only secondary parts of vertebræ. Finally, .T. F. St. Hilaire, wishing to settle so many uncer amHes, asserted that wc ought to begin by dctcrmming strictly tlic characters and the conditions of a vertebra. Neglecting the conditions founded on adults and assuming

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and posterior portions are thin and extended in processes ; a rounded opening exists in it through which a portion of the central mass of the nervous system passes.

Its squamous portion and its condyloid parts correspond perfectly to the semi-arches, and the basilar process to the body of the vertebra, in

higher considerations, he demonstrated, that a vertebra is not simply a transverse section placed against other transverse sections, thus producing an accumulation of parts to which as a whole the term column is applied ; in a word, that it is not a single bone, but an osseops system formed of nine elements, which may or may not be united, and essentially continue ;he same {Considerations gencT ales sur la vcrlèbre; in the Mémoires du Muséum, vol. ix. p. 89 . — Sur le système intra-vertébral des insectes, in the Annales de la médecine â– physiologique, vol. ii. p. 233). These elements "are an unmated and central nucleus, the cycléal, to W'hich are adapted two rings, an upper and a lower, which contain the first a section of the medullary system, and the second one of the sanguineous system. Each of these rings is composed of four pieces, namely, the upper of tw-o périal and two épiai, and the inferior of two paraal and two cataal. general, one of the two increases always at the expense of the other, and when the excess is extreme, the elements of the smaller ring appear as very small processes. Like the difi'erence between the two extreniities of the central axis of the nervous system, one of which is attenuated, the other, on the contrary, increased and enlarged like a ball, tliis difference not only requires an increase in the surface of the principal pieces, but also, and â– with equal influence, the concurrence of all of them which must then combine uniformly, without any dismemberment of external parts or projccticns, that is, simply become pieces of the external septum. J. F. St. Hilaiie thus explains the defect of projections and processes, which forms one of the distinctive characters of the largest skulls. The osseous system having then only to inclose a medullary mass, it maintains as few external relations as possible, while farther on, having to protect only a very small mass, the spinal marrow-, it becomes rough externally, and all its superficial points are formed of strong processes for each njuscular part. Leaving these general ideas, to which it was necessary to arrive to determine this question, and to deduce true philosophical conclusions in regard to the cephalic bones, J. F. St. Hilaire concludes {Composition de la tête osseuse de l' homme et des animaux, in the Annales des sciences naturelles, vol. iii. p. 173) lo consider the hqad, leaving out the lower jaw, as formed of seven vertebra?, which are named and composed as follows : 1st, the cerebelloid {cérébelleuse) vertebra comprising the basi-sphenal (the posterior segment of the basilar bone), two superoccipital (the upper occipital bones), tw-o stapedial (the stapes), two ex-occipital (the lateral occipital bones), and two incudal pieces (the incudes) ; 2d, the auricular vertebra, comprising the otosphenal (anterior section of the basilar bone), two parietal, (the parietal bones), two tympanal (the rings of the tympanum), two petrous (the petrous portion of tire temporal bones), and two malleolar (the mallei) ; 3d, i\\o optic or quadrijumal vertebra, comprising the hyposphenal' {the posterior body of the sphenoid bone), two cotyleal, two pterygoid (the large wings of the sphenoid bone), two temporal (I he squamous portion of the temporal bone), two serrial (the large portions of the tympanum) ; 4th, the cerebral vertebra, comprising the ento-sphenat (the anterior body of the sphenoid bone), two ingrassial (the wings of Ingrassias), two ad-orbital (the orbital portions of the maxillary bong), two jugal (the ma-[ar botres)j two herisseal (the internal pterygoid processes) ; 5th, the ocular vertebra, comprising the ethmosphenal (the body of the ethmoid bone), two frontal (the frontal bone), two ad-guslal (the external pterygoid processes), two palpebral (the tarsal cartilages), and two ethmophysat (the upper turbinated bones) ; 6th, the nasal vertebra, comprising the rhinosphenal (the plate of the ethmoid bone), two nasal (the bones of the nose), two palatal (the palate bones), tv.-o lachrymal (the unguiform bones), two rhinophysal (the inferior turbinated bones) ; 7th, the labial vertebra comprisiuo- the protosphenal, two ad-nasal (the intermaxillary bone), two vomeral (the \'omer)° two addcntal (the dental parts of the maxillary bone,) and two protopliysal (the cartilaire of the nose. As to the lower jaw J. F. St. Hilaire says, independently of the seven cephalic vertebrae, admits in each of these branches seven pieces at most, viz. the subdental, the sublachrymal, the subpalpebral, the subjugal, the subtemporal, thesuùTupéal, and the sub-uccipital. Thus, according to him, the head is composed of seventy-seven bones, the skull and face of sixty-three pairs, and seven which ate tmmated, and the lower jaw of seven pairs. F. T.

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regard to form and situation. The squamous part represents the spinous process, and the condyloid portions are analogous to the transverse and articular processes.

The different parts of which it is composed are developed like those of the vertebræ ; the squamous and the condyloid portions appear before the body, and the different pieces which form the posterior and lateral portions fuse together before they unite to the body.

The body unites with the central portion of the sphenoid bone forward, and its lateral parts articulate with the cervical vertebra backward, in the same manner as do the analogous portions of the vertebræ with each other.

Similar muscles are attached to the occipital bone and the different vertebræ. So too this bone contains like each vertebra a part of the central portion of the nervous system. Between it the first vertebra backward and the temporal bone forward we find the same foramina as between the other vertebræ, and these holes give passage to he same nerves and vessels.

As the bodies of the other vertebræ most generally fuse with each other in some parts at an advanced age, so the bodies of the occipital and the sphenoid bones always unite in a single bone. Their fu.sion however takes place sooner. Finally, as the last lumbar vertebra often unites to the sacrum, so the occipital bone tends very much to unite in different ways with the first cervical vertebra.

2d. The sphenoicl portion of the basilar bone and the frontal bone taken together, represent the- second of the anterior vertebræ composing the skull. We may also consider them as composed of several imperfect vertebræ.

In regarding them in the first point of view, the body of the sphenoid portion corresponds to that of the vertebra. Its two wings and the frontal bone represent its lateral portion. Most of the frontal bone and the large wing of the sphenoid bone are in fact analogous to the posterior and superior part of the semi-arches, as the malar process of the frontal bone and the inferior pterygoid process correspond to the articular and the transverse processes of the vertebræ. We must consider the frontal bone as belonging to the anterior ^rtebra of the skull, because the lateral parts of the sphenoid portion a^ne do not curve to meet one another, and do not unite with the body to form a ring inclosing the anterior part of the brain, while this ring is produced by the assistance of the frontal bone.

The very complicated ossification of this vertebra occurs according to the same laws as that of the vertebræ of the trunk. Those pieces which correspond to the lateral parts ossify long before the body of the sphenoid portion ; and it is a normal condition, that the two lateral halves of the largest portion of the arch of the frontal bone unite in the same manner as the semi -arches of the â– (i'ertebræ. If the lower part of these lateral pieces unites earlier with the body of the sphenoid portion, thus differing from what occurs in the vertebræ, this difference is made uj) by another circumstance, viz. that the body

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of the sphenoid portion does not completely develop itself, or does not acquire its sinuses, until the pieces of the frontal bone are fused.

Several smaller vertebræ may be demonstrated in this large anterior vertebra of the skull. In fact, we can imagine the sphenoid portion formed of two vertebræ ; a posterior, which is larger, and represented by the body and the large wings, and an anterior, which is smaller, and formed by the small wings ; and we can suppose the frontal bone either as a portion of this anterior vertebra, wdrich would then be much larger than the posterior, or as the arch of a vertebra of wdiich the body is not developed, since the arches of the true vertebræ are always formed before their bodies.

The central vertebra of the skull is formed by the temporal and the parietal bones. The temporal bones represent a vertebra divided at its lower portion into tw'o parts by the basilar bone. The parietal bones and the squamous portion with the zygomatic and the mastoid processes of the temporal bone, represent the semi-arches and processes ; while the petrous portion of the temporal bone corresponds to the body of the vertebra. But we may also, as in the anterior vertebra of the skull, consider the parietal bone only'- as the rudiment of a particular vertebra, and regard the temporal bones as two halves of vertebræ, entirely distinct from each other.

Here also the parts of the arches are developed sooner than that of the body, and it is remarkable that of all the sutures, the sagittal suture is most frequently and the soonest effaced ; so that the semi-arches unite on the median line before they blend with the other portions.

The ethmoid bone differs so strikingly from all the other bones of the skull, that at first view we cannot perceive the least relation between them. We may, however, represent it as a fourth anterior and inferior vertebra of the skull, which, pressed in between the others, would not be developed in a ring, and would be flattened from one side to the other. We may, however, consider its perpendicular plate as the body, and its lateral portions as the semi-arches.

Here, as in the rest, the lateral portions ossify before the central part.

§ 647. In the bones of the face, the analogy' with the vertebræ is less easily demonstrated. One great point of resemblance is here deficient, viz., the relation with the central pan of the nervous system. We may, however, consider, in some measure, the upper maxillary bone as a large facial vertebra, of which the other bones of the face are a compliment. Y/e may also compare the lowmr maxillary bone with the upper part of the sternum and the upper ribs, and the styloid processes and the hyoid apparatus with the lower part of the sternum and the lower ribs ; for their semicircular form, their convexity forv ard, their concavity backward, their movable articulation with the skull, and their situation before it, establish a general correspondence with the sternum and with the ribs, in regard to form and connections ; and more so, because the upper ribs are united with the upper part of the sternum more intimately than the lower ribs are with the lower part of this bone ; precisely the same as the lower maxillary bone constitutes a single bone,

VoL. I .58

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while the hyoid bones and the styloid processes always form several distinct pieces.

We may also add, in favor of this analogy, that as the lower maxillary bone and the ribs are among the bones which are developed the first, and as the ribs form long before the sternum, so, too, the lower maxillary bone generally corresponds to the ribs fused together, and is composed only of two halves, the intermediate cartilage being gradually effaced. When two special nuclei are formed in this cartilage, as sometimes but rarely happens, the analogy is still greater ; since these nuclei, which correspond to the pieces of the sternum, arise long after the lateral portions.(l)

§ 648. Finally, we may compare the whole bony head to a large vertebra, composed of several, which are smaller and immovably articulated with each other, and accompanied by some rudiments of ribs fused together. This method of considering it is much more admissible, because the bones of the skull and sonre of those of the face tend to unite in a single jriece ; and even irr young subjects, we not unfrequently find all the sutures effaced, and then the head is composed of three bones only, which move on one another, — the lower maxillary bone and the hyoid bones anteriorly, and the collection of the bones of the skull and face posteriorly.

§ 649. The differences of the head at different periods of life are very great.(2)

They regard principally 1st, /orm ; 2d, mass; Zà, number; 4th, //le mode of union of the hones ; 5th, the form of the ichole ; 6 th, the proportion between the sJcuU and the face.

1st. The form. The bones of the head are much less rough and uneven, and their eminences project less, the younger the organism is. But those of the skull, or at least the occipital bone, the parietal bone, and the frontal bone, differ at different periods of life, inasmuch as from the fourth month of pregnancy to the end of the first year of existence, they are much less uniformly bulging than at anterior and subsequent periods ; but they project considerably at their central part, where the point of ossification develops itself ; so that the upper and lower portions there unite at an almost right angle. Before the fourth month, the bones of the skull are much flatter than in the rest of life, and more so as they are smaller.

2d. The mass. The boires of the head increase in extent, thickness, and weigr4, from the commencemeirt till the termination cf their development in the adult age ; but after this time, and till old age, they always diminuh in these three relations. Hence, in advanced life they are thinner, oftea perforated in several parts, especially where they are

(1) It seems less proper to compare the jaws to limbs, and the hyoid hones to the pelvis, as Oken has done> although it is not diflBcult to trace the cavity of the chest in the nasal fossæ, and that of the abdomen in the oral cavit y. It is perhaps from the considerable development oI the cephalic vertebræ and brain, that the other bones of the head can become only the rudiments of the ribs and sternum fused together.

(2) Recherches sur le crMic humain, by Tenon; in iifém. de L' Instil, sc. phys. et math., vol. i. p. 221-233. — Spix, Cephalogenesis, Munich, 1816.

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naturally thin, as the external and anterior part of the large wing of the sphenoid bone, and the orbital portion of the malar bone ; from this cause, the malar bone is frequently separated from the sphenoid bone in this place ; the sphenoidal fissure is often very extensive ; the maxillary bones are narrower by the entire height of the alveolar edges; and filially, the skull becomes lighter and smaller.

The différence of weight between the skulls of old men and those in mature age is much greater than that of volume. The skull of a female seventy years old, now before us, weighs fourteen ounces, and that of a girl twenty years of age weighs twenty-four ounces ; the first is nearly one half lighter than the second.

3d. The number of the bones of the 'head differs at different periods of life. At first the number is smaller, because ossification does not commence in all parts at the same time. Next, the bones are more numerous, because some bones are developed by several points of ossification, whence result separate pieces, which gradually unite.

4 th. The connection of the bones of the head is much looser the younger the subject is ; because the bony pieces are less extensive and are separated by larger intermediate cartilages. In very old persons, the bones which are united, during the greater part of life, by a simple immovable cartilaginous substance, almost always fuse together. This is the case particularly with the parietal bones which unite with each other, or with the frontal and the occipital bones, and it is true also of the ethmoid bone which joins with the inferior turbinated bone, while the latter is fused with the upper maxillary bone.

5th. In the early periods of life, the whole form of the head is much rounder than at an advanced age, which is particularly owing to the small development of the fece which the skull overreaches in every direction, and which is proportionally much smaller the younger the fetus is. In fact, the difference between the greatest length and breadth of the head is much greater the younger the fetus is, but it bulges more in all parts of its circumference, which makes its general form more round. We remark especially, during the early periods of uterine existence, that the skull is much broader aird less compact in the region of the temples thair it is afterward, and that the frontal bone, the parietal bone, and the occipital bone, are much more bulging. In a later period the bones sink remarkably.

The more rounded form of the skull during the early periods of pregnancy also results from the slight development of its base. In fact, this is shorter and narrower, and forms with the lateral and posterior faces a more obtuse angle.

§ 650. The form of the bones of the head, and consequently of the whole bony caAty, varies very considerably in the different races.(l) The differences in this point of view are more or less evident in all directions and in all regions. Hence the facial angle of Camper (§51)

(1) Blumenhach, / lecades collectionis suæ craniorum diver sarum gentium illustrât«, Gottingen, 1790-1814.

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Avill not measure them exactlj^, since it indicates only the direction of the anterior part of the skull and face, and gives only a general idea of the profile. We must then, at the same time, employ other means to determine it. Thus, on the one hand, we practice .the method recommended by Blumenbach,(l) that is, we embrace as much as possible all the peculiarities with a single glance, looking from behind forward, while the head rests on the lower maxillary bone, so that the malar bones may be horizontal ; 2d, we follow Cuvier's method, which consists in looking at the head from above downward and from before backward, to judge of the relations of capacity between the skull and the face.

We have already mentioned (§ 34) the results of these measurements, which furnish the principal distinctive characteristics of the human races.

The difference between the skull and the face in the relation of their respective capacities, is most important. The difference is most favorable to the skull in the European race ; and most unfavorable to it in the Ethiopian. Thus, the skull of a negro, compared with thirtysix skulls of Europeans, contained less wmter than any of them (2). •

Besides these differences of races, there are others which establish a difference more or less remarkable in the skulls of different people belonging to the same race.

The nations of the south, in whom we see the purity of the Caucasian race, or those which are most allied to it, as the Gieeks and Turks, differ from all other nations belonging to this race by their very round heads. (3)

CHAPTER IV.

I. GENERAL REMARKS ON THE ANOMALIES OF THE BONES OF THE HEAD.

I. OF THE CONGENITAL DEVIATIONS OF FORMATION.

§ 651. The congenital deviations in the formation of the bones of the head, affect their number^ forin^ connection, and size, and are for the most part more or less dependent on their mode of development. These four conditions are almost always united. We can, however, refer to one or another of them, only the essence of every deviation of formation of a bone of the head, since the number of these last never increases, like those of the trunk and extremities, by the formation of new pieces, but by the division of the primitive bones into several, so that we remark proportional differences in the form, connections, and size of the bones, the division of which has increased the whole number.

(1) De variet. gen. hum.nat., Gottingen, 1794, p. 203.

(2ÃŽ Samnarez, Principles of Physiology, London, 1798, p. 163.

(2) For other differences which are less constant, see the work by Bluincnbach already cited, and Soemmerings Osteology.

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I. ABSENCE AND SMALLNESS.

§ 652. The bones of the head are entirely deficient in aceplialia vera. In those cases of acephalia which are somewhat more perfectly developed, we rarely find a slight rudiment of a head composed of several bones.(l)

After this state, comes, as regards its external form, the acephalia falsa, in which the base of the skull and the face are generally regularly developed ; but in which also the bones, or the portions of the bones which form the vault of the skull, are entirely deficient, or are very small.

Next comes that state of the bones of the skull which exists in encephalocele, when several of these bones, or one only, (generally the occipital bone,) is but slightly developed ; and a portion of the brain, or serum collected between it and its envelops, projects through the opening.

Next follows the arrangement of the bones of the skull in hydrocephalus, where they are more or less distant from one another, and are often separated by unossified spaces.

The next state is the permanence of the fontanelles, which sometimes remain, in one or several parts, during life.

The state which is the least abnormal, although usually attended with some degree of imperfection in the intellectual faculties, on account of the corresponding state of the brain, is the smallness of the head, characterized by the flatiress of the anterior portion cf the skull, aird by its narrowness in the trairsverse direction : this is principally seen in ideots(2).

I. SEPARATION OF THE BONES OF THE HEAD. ,

§ 653. The best name for the abnormal bones, resulting from this division is, that of honès of the sutures {ossa stdurariim).{3) This in fact is the only general character we can assign to them, since they are not developed, except at the circumference of the concave bones ; and never, or at least but very rarely, within them. When the latter is the case, the abnormal bones form only between those parts of bone wirich are transiently separated, as between the different pieces of the occipital bone ; and usually unite when the development is finished. The terms triangular bones {ossa triquetra) and ivormian bones (4)

(1) Curtius, De monstro humano, Leyden, 1762. — .YIeckel, Handbuch der pathologischen Anatomie, vol. i. p. 151.

(2) Grediug', in Ludwig-, Adv. med. pract., vol. ii. and iii.

(3) Berlin, Traité d'ostéologie, vol. ii. p. 470. — Bose, De suiuris cranii, Leipsic, 1763. — Monro, Asfndluncommonjbrtiœnumber and size qf the ossa triquetra, in the Edin. med. essays, vol. v. no. 16. — Van Doever^i, Spec. obs. acad., cb. viii. — Sandifort, De ossiculis suturarum, in Obs. anat. path, book iii. chap. ix. and book iv. chap. X. p. 136-141.

(4) These boneä have been called also intcrcalia or epactalia. One of them occurs frequently in the posterior fontanelle ; it is the proper epactal bone, the triangular hone of Blaes, the os epactale, s. gccthianum of Fischer. (G. Fischer, Observata qucedam de os epactali sen Goëthiano palniigradorum, Moscow, 1811. — Adversar.

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{ossa rrormiana)^ are less suitable when considered generally. The hrst term, however, is not perfectly appropriate, as the division of the frontal bone into two lateral portions also enters into this anomaly, although the relations of this bone with those around it are not changed.

These bones are remarkable in several respects. In fact, 1st, their formation is governed by very precise laws ; 2d, they depend, in great part, on the normal development of the bones ; 3d, for the most part they establish striking analogies with animals.

1st. These bones are formed according to constant laws. The following circumstances prove it :

a. They are usually arranged more or less symmetrically, so that we rarely find them on one side of the bod}' only ; and when unmated, they usually extend as much on one side as on the other.

b. They occur more particularly in the cranium, and much more rarely in the face.

c. They are not equally common in all parts of the skull. They are observed most frequently between the occipital bone on one side, and the parietal and the temporal bones on the other. They are most generally situated in the lambdoid suture, more rarely in the mastoid suture. The parts in which they are next most freciuent, are the squamous suture, especially at its anterior extremity, between the large wing of the sphenoid bone, the squamous portion of the temporal bone, and the frontal and the parietal bones. They are more rare in the sagittal suture, where they are seen principally between the two parietal and the frontal bones, consequently at the anterior extremity of this suture. They are least common between the sphenoid bone and the adjacent bones.

In the face, th^ bones of the sutures are met with principally between the os planvTjff|.Df the ethmoid bone and the frontal, the unguiform and the upper maxillary bones, and also between the latter and the unguiform bones. They are more rare between the two upper maxillary bones. It is equally unusual to find the lower maxillary bone or the malar bones composed of two parts.

d. We may state as a general rule, that they are developed most frequently in the places where large cavities are to be filled. They are very frequent in the fontanelles, and are most common in the posterior, and next in the anterior lateral, middle lateral and the posterior lateral fontanelles.

e. They vary much in size. Sometimes they are only small pieces of bone, and sometimes the whole bone is divided into two equal parts. Thus, the occipital bone is sometimes divided into an upper and a lower portion, and the frontal bone is formed of two lateral portions of equal size. There are numerous degrees intermediate between these two extremes.

anatoviica, Moscow, 1819. Another, almost as common, is situated in the temporal fossa. Beclard proposes to call it the crofophal bone. The others occupy the occipitoparietal suture, .the place of the posterior and inferior fontanelle and the parietal suture. !*'â–  •

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f. The cause of the abnormal want of union between the parts of bone, is not always manifest. Although the anomaly is usually attended with an accumulation of serum within the skull (hydrocephalus), and with the distention of the ossifying surfaces ; we cannot, however, say it is owing to this distention, and suppose, with Blumenbach(l) that the fetus has been affected with hydrocephalus, which has been cured.

2d. The formation of these pieces of bone depends, in great part, on the normal development of the bones of the head. In fact ,

а. The separation of the frontal bone into two portions is normal from the origin of this bone till the first year of life.

б. The occipital portion of the basilar bone forms gradually by the union of eleven pieces (§ 543), and these are the pieces which are abnormally separated.

c. The temporal bone is also formed by four nuclei (§ 554) ; and these are the nuclei which remain more or less sensibly distinct.

d. The small bones of the sutures are most usually formed by the natural development of the bones of the head, since new nuclei always form on the circumference of the primitive germs of bone, which are smaller and more distinct, and which unite with them in one mass when the development proceeds regularly.

All the bones of the sutures however, do not depend upon the abnormal division of the separate pieces of bone, which form only one piece in the normal state ; and we cannot consider them all as resulting from an imperfect development. In fact, those in the large and the anterior lateral fontanelles, and in the squamous suture, and also the division of the squamous portion of the temporal bone and of the frontal bone into two parts situated one above the other, are not normal, but are distinct and special formations.

3d. It is generally very easy to trace the analogy between these abnormal bones and the structure of animals.

а. In most animals the frontal bone is composed of two lateral halves.

б. The separation of the occipital bone in different osseous pieces is also an arrangement which remains in many animals during life, and in others until birth. In many reptiles this bone is divided during life into a basilar, an articular, and a squamous portion, and this last itself into an upper and a lower portion. It is true that the first three parts and the squamous portion unite in a single piece in the mammalia ; but in many animals, as also in the fishes, the squamous portion is divided into two parts.

c. The mastoid portion of the temporal bone forms a distinct bone in the mole.

d. The primitive arrangement, that is, the insulation of the different nuclei of bone, remains during hfe in the gecko. (2)

(1) Knochenlehre, p. 180.

(2) Cams, Anatomic und Physiologic des Nervensystems, Leipsic, 1821.

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DESCRIPTIVE ANATOMY.

However, the other bones of the sutures, which constitute positive anomalies, do not appear in animals.

From what precedes, it follows that our views upon the origin of these bones are more extensive than certain anatomists have thought,(l) since we can say, tha't most of them are produced by a development deficient in energy.

§ 654. The development of these bones forms an unusual number of sutures, since its essence consists in increasing the number of pieces of bone at the expense of the normal bones.

The slightest deviation from the normal state is the existence of a suture called the frontal suture {sutura frontalis) between the disunited portions of the frontal bone, which sometimes extends through the whole bone, and sometimes exists only at its upper or lower part, more fi'equently in the former. As this suture is continuous with the sagittal suture, and cuts the coronal suture at a right angle, those heads which have them are termed capita cruciata. The other supernumerary sutures arising from the same source are usually small and imperfect, and do not extend the whole breadth or height of the bone. Sometimes, however, we find the occipital bone and more rarely the parietal bone entirely divided by a transverse suture into an upper and a lower half

We must remark, in regard to this, that the division is most frequent in the frontal bone ; it is more rare in the squamous portion of the occipital hone, and still less frequent in the parietal bones ; so that its degree of frequency is in direct ratio with the time during which the bone remains in its primitive form, or, more particularly, with the occurrence of deviations of formation in the primitive pieces.

If the number and situation of the bones of the sutures be such as to form along one of the usual sutures a chain corresponding to the normal form of the corresponding edges of the bones, which are wedged in between them, we then have double sutures {suturœ duplices), which are generally seen between several bones of the same skull, since these bones are usually developed in several regions of the skull in the same subject, but not in the same number.

The unusual distance between the bones of the skull, which is caused by hydrocephalus, is allied to the abnormal development of separate bones formed at the expense of the normal bones. Theq we have developed not only a greater or less number of bones of the sutures, but these are also separated by large unossified spaces.

Finally, we must arrange here the want of union between the palate-bone and upper maxillary bone on the median line, which essentially constitutes hare-lip. Another“ anomaly allied to this, and dependent on the same proximate cause, is the imperfect ossification of the skull-bones, which present from space to space hollow's filled with cartilaginous substance only. This anomaly is also seen in hydrocephalus, and is sometimes primitive and sometimes consecutive.

(1) Hildebrandt, Lehrbuch der Anatomic, vol. i. p. 21C.

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III. OF THE ABNORMAL UNION OF BONES OF THE HEAD.

§ 655. The state opposite to that which we have examined supervenes usually at an advanced age ; but it is not rare in young people, and is frequently seen in hydrocephalus, in consequence of the disappearance of the cartilaginous layer interposed between the adjacent bones.

These anomalies are also subject to certain laws :

a. The pieces of bone which remain separate and distinct beyond the proper periods usually fuse with the adjacent bones sooner than these unite with one another.

b. Of all the bones of the skull, the parietal hones unite soonest and most frequently : their union commences generally, but not always, in the centre of the sagittal suture. The temporal bones and the occipital bone unite less frequently, and the frontal bone still less so ; in regard to which we must observe that the central portion of the coronal suture is usually the first to disappear. The union of the frontal and the temporal bones, of these latter with the sphenoid bone, and of the ethmoid bone with the adjoining bones, is more rare.

In the face, the inferior and the middle turbinated bones fuse with the upper maxillary bone, the vomer unites with the sphenoid bone, and the two nasal bones with each other.

§ 656. The bones of the skull sometimes become unusually large. This state generally attends hydrocephalus, and the anomaly becomes very striking when we regard the base of the skull at the same time, since we there see more or less sensible marks of the compression caused by a mechanical power acting from within outward.

§ 657. The bones of the skull vary also in thickness. In advanced age they are thinner than during the early periods of life. The same thing is seen in hydrocephalus. However, at the end of life they become thicker, but also very spungy. They are also thicker in ideots ;(1) although then the relation of causality between this state of the skull and that of the brain probably is not always the same, since the excessive development of the bones from within may be a primitive anomaly, and cause a compression of the brain which is injurious, or their unusual increase may depend upon a want of nutrition and on the shrinking of the brain. Besides, the thickening of the bones of the skull is attended sometimes with an increase and sometimes with a diminution in the density of their tissue.

§ 658. The bones of the skull are sometimes abnormal by a defect in symmetry, so that they, and consequently the whole head, appear oblique. This state depends perhaps upon a primitive congestion of serum in the skull, and upon the unequal pressure exercised by the fluid. It sometimes attends mental derangement.

(1) Grediiig, iu Ludwig', Adv. med. pract., yol. ii. p. 456, vol. iii. p. 600. VoL.I. 59

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The bonos of the skull present other anomalie.s, especially in cretinism.(l) Although the form of the head in cretins is not always exactly the same, the skull however is generally low, less bulging particularly in the frontal and the occipital regions, and on the contrary unusually broad from side to side ; the base from before backward is short and somewhat compressed ; the sutures are more or less completely effaced, and filled with numerous bones of the sutures. In regard to particular bones, the basilar bone differs most from the normal state ; it is small, flat and even concave at its upper part, while its articular parts and the occipital foramen are more or less oblique and sometimes almost perpendicular, so that the articular portions look directly forward, and the basilar process and the body of the sphenoid bone are straight and very elevated. s

It often happens also that the skull is more or less oblique, especially in the moderate degrees of cretinism, which obliquity seems to depend upon the existence of the anomalies on one side only.

§ 659. The consecutive or accidental deviations of formation in the bones of the head are,

1st. The solutions of continuity. Sometimes these are fssur es {fissura), which are often extremely small, and are then termed capillary openings. They difier from the normal or abnormal sutures in being straighter, in the periosteum not adhering with as much force as usual, in not having cartilage upon their edges, and in being seen in the places upon which the wounding cause has acted. We call these counter-fissures {contra-fisstirœ) when they supervene on the side opposite to that on which the blow has been struck. Both extend from one bone to another, passing over the sutures. Sometimes there are depressions (depressiones), when there is no solution of continuity, but a piece, wholly or partly detached, is pressed in. Depressions can take place without a fracture in youth, because of the thinness and the elasticity of the bones of the head.

2d. The separation of the connections of the bone {dia.stasis), which, if the sutures are perfeetly developed, can be caused only by a very violent mechanical action.

SECTION III.

OF THE BONES OF THE EXTREMITIES.

§ 660. The bones of the upper and lower extremities correspond not only on the right and left sides, but also upward and downward ; so that the lower limbs are a repetition of the upper, in respect to number

(1) J. F. Ackermann, Ueber die Kretinen, cine besondere Menschenabart in den Alpen, Gotlia, 1790. — Poderé, Essai sur le goitre et le crétinage, Turin, 1792. — Michaelis, Ueber die Kretinen ira Salzburgischen, in Blumenbacli, Med. Bibl., vol. iii. p. 658. — Joseph and Charles Wenzel, Ueber den Kretinismus, Vienna, 1802. — H. Reeve, Some account of cretinism, in the Edin. med. journ., vol. v. 1809, p. 31-36. — Iphofen, Der Cretinismus, philosophisch und medicinisch untersucht, Dresden, 1817.

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and form, and the mutual relations of the different sections of which each limb is composed.

§ 661. Each is composed of four grand sections : the first is formed principally by one large bone ; this is the scapuhr portion {Portio scapularis) in the upper limb, and the iliac portion {P. iliaca) in the lower; the second includes one cylindrical bone, the humerus in the upper extremity and the femur in the lower ; in both, the longest and the next section is composed essentially of two bones, which are the radius and the ulna in the fore-arm, and the tibia and the fibula in the leg ; the fourth comprises, in the upper extremity, the bones of the hand, and below, those of the foot, which correspond with each other almost perfectly in number, form, and divisions.

CHAPTER I.

OF THE BONES OF THE UPPER EXTREMITIES.

ARTICLE FIRST.

OF THE BONES OF THE SHOULDER.

§ 662. We find on each side two bones in the region of the shoulder : the larger is flat, situated backward and a little on the side ; the smaller is cylindrical and is situated at the anterior and superior part of the shoulder ; the former is termed the scapula, the latter the clavicle.

I. OF THE SCAPULA.

§ 663. The scaptda (omoplata) has in general the form of an equilateral triangle, the base of which looks upward, and it extends, when all the muscles which unite the bones of the trunk and those of the superior extremities are inactive, from the second to about the seventh rib, and its internal edge is nearly an inch distant from the lateral portion of the spinal column.

§ 664. It has three edges ; the internal is longer than the external, and hence is called the base {basis scapidÅ“). In its upper fourth, its direction is from above downward and from without inward, and it is more or less convex. After leaving this point, it proceeds almost directly downward and outward, and is parallel to the external. The latter, which unites to it at an acute angle, is most prominent at its lower part, where it is straight and very thin, while it is slightly concave and much thicker at its upper portion ; so that the anterior and posterior faces of. the scapula, particularly the latter, pass much beyond it. The upper extremity of this edge enlarges still more, to form a superficial oblong cavity, which is narrower upward, and is called the glenoid cavity {cavitas glenoidea), and which projects very far outward. The upper edge is oblique from within outward and from above

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downward, and it is slightly concave at its uiiper part. Toward its internal extremity, we see a semicircular grove {indmira semilutiaris, himda), which is more or less distinct, but always distinguished from the rest of the concavity by a greater depth. This fissure is sometimes changed into a foramen by a slip of bone.

Where the superior and external edges unite, the scapula extends into a process curved upward and forward, the coracoid process {processus coracoideiis) . The upper face of this process is turned inward and its lower face outward.

§ 665. The posterior and external face of the scapula is divided into two portions by an eminence which extends obliquely from the internal to the external edge, and is called the spine of the scapida {spina scaptdÅ“) ; the upper is smaller, and is termed the fossa supra -spin at a ; the inferior portion is much larger, and is termed the fossa infra-spinata. The whole external face of the scapula is a little convex backward, particularly in the fossa snpra-spinata. The spine itself begins near the internal edge, by a small, triangular, broad elevation, which inclines downward very much, and gradually enlarges from within outward. It does not go directly backward, but is inclined a^t the same time from below upward and from before backward, so that it makes an acute angle with the supra-spinal portion, and an obtuse angle with the infraspinal portion.

It does not extend as far as the external edge, but stops at some distance from the posterior edge of the articular surface ; so that an interval exists betwmen this and the last, which is the neck of the scapida {colluni scaptdce). The direction of the spine now changes, and it enlarges very much from without inward. This part, which is found about an inch distant from the glenoid cavity, and v/hich projects upward and inward, is called the acromion process ; it is the highest point of the scapula. It confines the motions of the head of the humerus inward and upward, as the coracoid process limits thbm forward and upward. Its posterior edge presents, immediately behind this upper extremity, a small straight surface which is covered with cartilage.

§ 666. The anterior face is more uniform. It presents only a slight depression, which corresponds to the spine ; and we can distinguish on it also a supra-s]rinal and an infra-spinal portion. This latter usualty presents three small ridges, which ascend upward and outward from the base, and which unite nearly in the centre, and between which are superficial depressions. All the anterior face is slightly concave.

§ 667. The infra-spinal portion of the scapula is the thinnest. The bone becomes thicker toward its edges, but principally toward the internal, and on the side of the articular eminence. It is a little thinner in the coracoid process, and still more so in the spine, although this is thicker than the fossæ.

§ 668. The scapula first appears toward the end of the second month of pregnancy, as a flat and irregularly quadrilateral bone, on the surface Off wdiich the spine is not yet vi.fible ; this is developed at the

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third month of pregnancy, and extends from its origin beyond the upper edge.

In the full grown fetus the processes appear, hut are still almost entirely cartilaginous. The spine never develops itself by a single point of ossification, but appears as a prolongation backward of the posterior face. Gradually, however, we see a distinct germ of bone for the coracoid process, which exists even in the full grown fetus, or at least appears in the first year. It is, however, usually united with the rest of the scapula in subjects fifteen years old. At the point of union, and about the period when it is finished, there is developed, above and at the base of the coracoid process, a rounded nucleus of bone, which remains separate and distinct longer than the other processes. Afterward, when the coracoid process is united, we see also special nuclei of bone for the upper part of the acromion process, for the lower angle, and for the base ; these do not unite to the principal portion until the growth of the subject is matured. The size of the osseous nucleus of the acromion process varies much ; for sometimes it is only a narrow band, and sometimes forms most of this process.

§ 669. The deviations of formation in the scapula are particularly its continuance in an early stage of development. Thus, sometimes the portion of the acromion process remains separated during life, being united to the rest of the bone only by cartilage.

Sometimes the process of ossification is not perfect in other points, so that a greater or less portion of the fossa infra-spinata remains cartilaginous, which is singularly analogous with what is observed i)i many mammalia, especially the pachydermaia.

II. OF THE CLAVICLE.

§ 670. The clavicle {clavicida^ clavis, os jugidi, furcula, ligiila) is situated on the line of separation between the neck and the chest, between the sternum and the scapula. It extends a little obliquely from before backward, from below upward and from within outwarA It is turned like an italic 6', so that the outer half is convex backward and concave forward, while the inner half is concave backward and convex forward.

We distinguish in this bone a body, a sternal exiremify, and a scapidar extremity.

The body is contracted from above downward. It, however, presents more or less distinctly three faces;' a posterior, smooth and concave from above downward ; an upper, oblique from above downward, and from behind forward, and very rough ; finally, a lower, straight or slightly concave, smooth or slightly rough. Among the angles, the upper, which forms at the same time the upper edge, is the only one which is seen distinctly. It is also rounded. We usually find one and sometimes two foramina of nutrition on its posterior face.

The anterior or sternal portion {pars sternalis) is the thickest, and mo.st evidently triangular portion of the clavicle'; it terminates by

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DESCRIPTIVE ANATOMY.

i mostly triangular, cartilaginous, but uneven surface, the base of

which looks upward, and sometimes has a more irregular and rounded form. At the beginning of this sternal portion, we often find on its anterior face a considerable and rough depression, and further outward a rough elevation.

The posterior or scapular portion {pars scapularis) is the broadest portion of the bone, and the flattest from above downward : on its upper face are muscular impressions ; on the lower, are asperities to which the ligaments are attached ; and at its external extremity is a larger or smaller cartilaginous articular surface.

§ 671. The clavicle is very remarkable in the history of the development of the organism, because it is one of those parts most proper to demonstrate the great difference which is presented in the form, and particularly in the proportional volume of one and the same organ at different periods of life. Notwithstanding its smallness, it appears very early, if it is not the first of the bones which develops itself Towards the middle of the second month of pregnancy, its length is about three lines, and it is four times as large as the humerus and the femur. At the third month of fetal existence, it is nearly twice as long as these bones ; and at the end of the month it continues larger than them. The humerus is larger in the fourth month ; in the full-grown fetus it is only one-fourth longer, while it is twice as long in the adult. The division of the clavicle into a body, a sternal and a scapular extremity is founded solely on the different dimensions of these regions, and on their relations with the adjacent parts, but not on their mode of development : for the clavicle arises by a single point of ossification, excepting always a very thin nucleus of bone, which forms very late on the anterior face of its sternal extremity.

§ 672. This bone is also one of those in which the sexual differences of the skeleton are most manifest. It is generally .straighterji and proportionally smaller in the female than in the male. Its greater straightness depends particularly on the lesser curve of its external portion, while in man it extends far backward and then comes forward The internal anterior half presents nearly the same curve in both sexes. The clavicle of the female is rounder than that of the male ; we however find clavicles of females perfectly like those of males, and vice versa. Sometimes of the two clavicles in the same body, one is constructed in the type of the male, and the other in that of the female. These two anomalies are a slight degree of hermaphrodism.

§ 673. The clavicle is articulated by its anterior extremity with the handle of the sternum, by its posterior extremity with the acromion process of the scapula, and also with the scapula and with the first rib by fibrous ligaments

§ 674. Sometimes a portion of the clavicle, particularly the external, is deficient, even when the upper extremity is otherwise normally developed ; and it is then replaced by a process of the scapula, which however is always thinner(l).

(1) Martin, Déplacement naturel de la clavicule : in Roux, Journal de Med., vol. xxiii., p. 458.

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471

ARTICLE SECOND.

OF THE HUMERUS.

A. NORMAL STATE.

§ G75. The arm-bone or the humerus {os hume7-i, os brachii) the third in size of the round bones, forms alone the bony foundation of the arm. Its body is slightly twisted ; it gradually becomes thinner from above downward, but is broader at its lower extremity. Its three faces are more marked at the lower than at the upper part, which is rounded rather than triangular. These faces are, when the arm is extended along the body, an anterior, a posterior, and an external. The first two are almost straight ; the upper part of the posterior face alone is convex, and its lower part is straight. The internal edge, which terminates the anterior and posterior faces, is very rough in the upper part of the bone where the anterior and posterior edges are hardly perceptible, while they are very distinct in the inferior portion, and become more so when examined still lower. The irpper extremity of the body enlarges considerably, particularly inward and backward. The foramen of nutrition, which is single, is found at the commencement of the lower third, on the anterior face near the internal edge, sometimes even on this or on the posterior edge.

It is extended into an upper process, the direction of which varies a little inward and backward from that of the body. Its greater posterior, inner, and upper portion forms a semi-spherical head {caput humeri), covered with cartilage, which is surrounded with a slight and somewhat rough depression. On the outer and anterior circuit of this upper process, are two eminences for the insertion of the muscles, the tuberosities {tubercula) of the humerus, one of which is three times as large as the other, is situated outward and forward, and is called the external, anterior, or larger tubercle {tubercidum majus, anterius, externum) ; while the other, smaller but more projecting, is called the smaller, posterior, or internal tubercle { T. minus, posterius, internum). From each of them proceeds a rough line, of which that of the large tubercle {spina tuberctili majoris) terminates in the internal edge, and that of the small tubercle {spina luberctdi minoris) is not more than a third or a fourth »as lon g as the body of the humerus, and disappears at this height. A groove, which varies in depth, exists between the tubercles ; this goes downward, forward, and outward, and soon disappears on the upper extremity of the internal faceof thebody ; this is Ûiebicipital groove.

The lower extremity is more complex than the upper. The bone is here a little broader, but is much thinner than at its upper end ; and is consequently flat. It terminates downward by an oblong, round, and cartilaginous projection, the surface of which is very uneven from several eminences and depressions. Its anterior or external portion is rounded, and extends much higher on the anterior or internal side of

472

DESCRIPTIVE ANATOMV,

the bone, than on the posterior or external ; it is the inferior head {eminentia cajnlata). The posterior or internal part is much larger, extends as high backward as forward, and is composed of two semicircular eminences, of which the external or anterior, situated at the side of the former, and separated from it by a fissure, is much smaller than the internal or posterior, Avhich is also separated by a considerable depression. These two eminences form the jmlley [trochlea ossis humeri). We observe over the inferior head a slight depression, called the small anterior fossa [fossa anterior minor) ; above the pulley and forward, another deeper depression called the great anterior fossa [fossa anterior major) ; finally backward, and also above the pulley a third depression, deeper than the other two, called the largest or Ûiq posterior fossa [sinus maximus, s. fossa posterior). .The last two cavities not unfrequently communicate by a large opening in the bone, which generally exists upon both sides of the body. The bone, too, is sometimes perforated with a large rounded opening over these articular eminences.

Besides these articular processes in which the lower extremity of thehumerus terminates, its anterior and posterior edges present two emmences which are not so deep, but serve as attachments to muscles : these are the condyles (condyli). The anterior and outer condyle is much smaller, and is termed also the epicondyle [condylus ßexorus). Most of the flexor muscles of the hand are inserted in it, and also in that part of the anterior face of the humerus over it. The posterior and internal condyle or epitrochleus, [co7idylus extensorius), which is three times as large, gives attachment to the extensor muscles of the hand.

§ 676. The humerus begins to form about the middle of the second month of pregnancy. Toward the end of this month it is still small, only about a line long, and flat. Perhaps it develops itself by two points of ossification, situated one at the side of the other, which grow together rapidly ; for in young fetuses we have seen a fissure extending from its upper extremity to its central portion. Even till the last month of fetal existence, the body only is ossified ; but at this period ossification commences also in the extremities, and first in the inferior.

This presents at birth only one nucleus of bone, which is not situated in its centre, but in the small head. Sometimes, and most generally, the body gradually extends into the pulley, or a single nucleus of bone is developed in the pulley, which fuses first with the head, then with the body. Some months after birth, we see an osseous germ in the upper extremity or in the place of the head, with which a second, in the large tubercle, unites afterward, and usually at the end of the first year ; these two nuclei fuse together before the whole extremity joins the body. Still later, the internal or posterior condyle develops itself by one point of ossification, which fuses sometimes with the body and sometimes also with the rest of the inferior extremity. This last unites with the body sooner, long before the subject is perfectly grown, while the upper remains distinct and separate until after this period. The

OSTEOLOGY.

473

internal tubercle fuses with the body much sooner than the upper, but much later than the lower.( 1 )

§ 677. The humerus forms, by its head, with the glenoid cavity of the scapula, an arthrodia ; its lower extremity is united with the two bones of the fore-arm.

B. ABNORMAL STATE.

§ 678. The humerus is sometimes entirely deficient, from a primitive deviation of formation, or in a greater or less portion when the upper limbs are more or less imperfectly developed. The degrees of this anomaly are very various ; for sometimes a very small stump only appears ; sometimes, when the development is more advanced and the fore-arm and hand only are deficient, the humerus becomes thin at its lower extremity, and terminates in one or two processes. (2)

We have already mentioned (§ 673) the union of the larger anterior and posterior fossæ.

ARTICLE THIRD.

OF THE BONES OF THE FORE-ARM.

A. NORMAL STATE.

§ 679. The bones of the fore-arm ar^ two, the radius and the cubitus or ulna^ which are nearly equal in s ize, are situated on the same plane, and are both articulated with the humerus ; but which are capable of executing very different motions, on account of the forms of their articular surfaces.

I. OF THE ULNA.

§ 680. The idna (ulna s. cubitus, canna major, focile majus) is longer than the radius, and this extra length extends above it. It deserves then to be examined first, partly on this account and partly because being less movable, it forms the basis of the bony frame of the fore-arm.

Its body gradually diminishes in thickness from above downward, and it is slightly curved in the form of an S ; for near the centre it approaches the radius, then separates from it, and again approaches it at its lower extremity. Its upper portion, which is the longest, presents very distinctly three faces ; these are, when the fore-arm is at rest, a posterior, an anterior, and an internal face ; but they disappear at its lower portion, where the bone becomes rounder. The posterior and the anterior faces are almost straight ; sometimes however the anterior is

(1) Albinus has pointed out, but very imperfectly, the order in which the nuclei of ossification are developed and united.

(2) Bonn, Thes. oss. murb. Hov., Amsterdam, 1783, p. 120.

VoL. I. 60

474

DESCRIPTIVE ANATOMY.

divided by a longitudinal eminence into two broad furrows. The internal face is always slightly grooved. The anterior edge, which limits the external and the anterior faces, and which looks toward the radius, projects the most and is called the crest of the ulna {crista ulna). At the upper extremity of the anterior face is a large eminence, which gives attachment to certain muscles, and is called the tubercle, or head of the ulna {tuber ulnœ).

The foramen of nutrition is usually situated a little above the centre of the bone, at the side of the crest, on the anterior or on the internal face. The upper extremity has the form of a hook, is the largest part of the bone, and is much thicker than the lower part. The upper and posterior part of this hook, the olecranon process {olecranon, processus anconæus), is directed perpendicularly from below upward ; it is slightly rough, and convex at its upper and posterior part, and its anterior portion is concave and faced with cartilage. Where the upper face is continuous with the lower, is formed the tuberosity of the olecranon {tuber olecranii). The anterior part of the hook, the coronoid process ( processus coronoideus), has a horizontal direction and is much lower. It presents an upper cartilaginous and concave surface, which is continuous at a right angle with the anterior face of the olecranon process, and is separated from it by a transverse fissure, which backward and inward usually presents no cartilage. These two cartilaginous surfaces form by their union a very deep cavity, called the large sigmoid cavity {cavitas se^ni-lunaris, sinus sigmoidcus, sinus lunatus mq;or),whieh is divided in its whole extent by a prominent line into two portions, of which the posterior is broader. Next to the anterior horizontal portion of this articular cavity, and joined to it at a right angle, we find, on the anterior face of the upper end of the ulna, the small semilunar cavity {cavitas semilunaris, sinus sigmoideus, sinus lunatus minor), which is much flatter, transverse, and also covered with cartilage.

The lower ami rounded extremity of the bone swells out a little, and hence is called the head {capitulmn idnae). Its inner and anterior part is covered with cartilage ; the external is extended into a small rounded process, separated from the rest of the surface forward and backward by a groove, which is called the styloid process {processus styloideus). The inferior face of the head is slightly channeled.

§ 681. The ulna appears as early as the humerus (§ 676), or shortly after it. In the full grown fetus it is composed of a single nucleus of bone, which comprises all the upper process. Later, and rarely before the sixth year, nuclei of bone are developed above and below it. We first see the nucleus of the lower extremity which forms the base of the head, with the lateral faces and the styloid process. A little later, there are are developed in the upper end the three nuclei of the olecranon process. Two of these are situated inward, one at the side of the other, and extend transversely from before backward ; the posterior is much larger than the anterior ; the third, which is the largest of all, is found externally, and very much resembles the patella, both in situation and in its round form ; these three nuclei concur but slightly to form the upper extremity of the ulna. They are not united with the body even at puberty ; the upper unite with it much sooner than the lower, which remains separate until the subject has attained its growth,

§ 682. The ulna articulates at its upper extremity with the posterior part of the articulating surface of the lower end of the humerus, or the pulley, the elevations and depressions of which correspond perfectly to those of the large sigmoid cavity. In a state of extreme flexion, the anterior and most projecting part of the internal edge of the coronoid process engages itself in the larger anterior fossa of the humerus ; when the fore-arm is extended, the olecranon process is received into the posterior fossa of this same bone (§ 675). The small lateral fissure of the upper extremity receives the commencement of the head of the radius, the inferior extremity of which turns around the convex and cartilaginous portion of the head of the ulna.

II. OP THE RADIUS.

§ 683. The radius {radius, facile minus) is much shorter than the ulna, and differs from it in being much thicker in its lower than in its upper part. It occupies the anterior region of the arm when in a state of repose along the body, and the external region when this limb is turned outward. It is considerably curved ; for its central part is convex forward and concave backward, while the upper and lower portions are almost straight.

We distinguish in the body three faces and three edges. The internal face is the broadest, slightly concave upward, and convex downward ; the foramen of nutrition is situated a little above the centre of the bone. The anterior face is very concave, the external is almost straight. The posterior edge, or the crest of the radius {crista radii), projects considerably, especially at its central part ; the anterior and external edges are very round, so that the inner face is insensibly continuous with the anterior, and this with the external, while there is a well defined limit between the external and internal faces. Near the upper extremity of the bone, we see on the internal face the tuberosihj of the radius {tuberositas radii), a considerable rounded, oblong eminence, which gives attachment to certain muscles and in which the posterior and the anterior edges unite. Above this point the bone slightly contracts, becomes round, and forms a-neck {collum), which is rather long, and follows a similar direction. The neck enlarges at its upper extremity, and with it is connected the head {caput radii), which is round, slightly concave above, and covered with cartilage in every part.

The body gradually increases while descending, and finally becomes very thick. It spreads especially from before backward, and supports the lower triangular process, the base of which is turned backward, and the summit forward. The summit projects a little beyond the inferior face, and this forms a small prominence, called the styloid process {processus styloidcus). The lower cartilaginous face is divided, by a small eminence, the direction of which is from within outward, into a posterior portion, which is square, and an anterior and triangular part. The posterior lateral face is also covered with cartilage, slightly excavated, and forms the semilunar notch {mcisura semilunaris). The anterior is almost straight. The external is convex, and has a large projection in its centre. On both sides of this projection is a considerable tendinous groove, which extends from above downward, and which contains another smaller.

§ 684. The radius appears at the same time as the ulna. It is already developed in the full-grown fetus, but is composed of only one part, the body. At this time its lower part does not much exceed that of the ulna in size, because this last is much thicker proportionally than it is afterwards. The osseous nucleus of the inferior process appears in its anterior portions first, but rarely before the end of the second year. The upper extremity does not begin to develop itself till towards the age of seven years ; it however fuses with the body long before the subject is fully grown, while the lower remains separate even after this period.

§ 685. The radius articulates by the upper face of its head with the small head on the lower articular surface of the humerus ; by the lateral face of this head, which is covered with cartilage, with the small semilunar cavity of the ulna ; by the semilunar notch of its low'er extremity with the cartilaginous surface of the head of the ulna ; finally, by its inferior face, forward with the scaphoid bone, and backward with the semilunar bone of the wrist.

§ 686. By the arrangement of the corresponding articular surfaces, the radius possesses the motions of flexion and extension with the ulna, but can also partially turn on its axis, while the ulna changes its position very slightly. It is so connected with the wrist, that the hand follows all its motions. If the radius turns from before backward and inward, crossing the ulna obliquely, the posterior edge being directed outward and the internal face backward, the back of the hand is carried forward and the palm backward, the arm hanging beside the body ; this is called pronation (pronatio). The opposite motion, which brings the radius and the ulna on the same plane, carries the back of the hand backward and brings the palm forward, is called supination {supinatio). In both cases the upper and lower extremities of the radius turn on the corresponding lateral faces of the ulna, which are faced with cartilage.

B. ANOMALIES.

§ 687. Sometimes one of the bones of the fore-arm is deficient, sometimes both. In the latter case, the hand is generally deficient ; in the former, the hand is often well formed.

ARTICLE FOURTH. OF THE BONES OF THE HAND.

A. NORMAL STATE.

§ 688. The hand comprises three regions, the carpus, the metacarpus, and the fingers. That face which looks outward when the arm is hanging down is called the back {dorsum manus), and the opposite face the palm ( palma, vola) : the former is convex, the latter slightly concave. The edge turned forward in the same posture of the arm is called the I'adial edge {mar go radialis), and the opposite edge is the idnar (JVf. cuhitalis). The faces of the different bones of the hand are then distinguished into dorsal, palmar, radial, and ulnar.

I. OF THE BONES OF THE WRIST.

§ 689. The lorist {carpus) is the uppermost and the shortest region. It is composed of eight, sometimes of nine bones, which are very irregular, do not ossify till after birth, are very closely united with each other, and articulate with the bones of the metacarpus. Beside the four regions which it has in common with all the bones of the hand, we distinguish in it a brachial face {facies brachialis) and a digital face {F. digitalis). The bones which form it are arranged in two rows, a posterior or upper, and an anterior or lower.

I. OF THE BONES OF THE FIRST CARPAL RANGE.

§ 690. The posterior range of the carpal bones comprises four, which are, counting from before backward, or from the radial to the ulnar side, the scaphoid bone, the semilunar bone, the pyramidal bone, and the pisifomn bone.

I. OF THE SCAPHOID BONE.

§ 691. The scaphoid bone {os naviculare, s. scaphoideum) does not perfectly deserve this name, for its form is very irregular. In fact it is boat-shaped in its upper and posterior portion ; but forward is a large projection, which makes almost one half of its mass. It is composed of two parts, which are separated by a narrower portion, and it may be compared to the figure 8. Its upper posterior part is broader but flatter than the inferior anterior portion. Its^ brachial face is convex and covered with cartilage.* The digital face is concave and divided by a rounded projection mto two semicircular portions, a posterior, smaller and plane, and an anterior, which is larger and very concave. The first may be considered the uhiar face ; the second extends to the anterior part. The brachial and palmar faces of this part are not covered with cartilage, although the radial and digital faces form a triangular surlixcc covered with a cartilage, which is divided by an eminence, the direction of which is from before backward, into two parts, the one longer and triangular, which is found outward, the other smaller, in form an oblong square, and turned downward.

§ 692. Although the scaphoid bone is one of the largest of the carpal bones, it does not begin to ossify till several years after birth.

§ 693. The scaphoid bone articulates, by its upper and cartilaginotis face, with the anterior triangular portion of the lower face of the radius (§ 685) ; by its ulnar face, with the semilunar bone (§ 696) ; by the posterior digital face, with the os magnum (§ 709) ; by its radial face, with the trapezium ; finally, by the anterior portion of its digital face, with the trapezoides (§ 704).

II. OF THE SEMILUNAR BONE.

§ 694. The semilunar hone (os lunatum s. semilunare) has a convex brachial face, which is covered with cartilage. This face is insensibly continuous with the convex palmar face, which has no cartilage, and with the straight dorsal face. The radial face is semicircular and entirely covered with cartilage. The ulnar face has the same form ; it is destitute of cartilage except on its upper, posterior, square portion. These last faces are straight. On the digital face is a deep cavity, which is covered with cartilage.

§ 695. Ossification commences as late as in the scaphoid bone.

§ 696. The semilunar bone articulates, by its brachial face, with the posterior square portion of the lower cartilaginous face of the radius (§ 685) ; by its radial face, with the scaphoid bone (§ 693) ; by its ulnar face, with the pyramidal bone(§699); and by its digital face, with the os magnum.

III. OF THE PYRAMIDAL BONE.

§ 697. The pyramidal bone (os triquetrum, trianguläre, cunéiforme) has its base forward and its summit backward. The internal and anterior smaller portion of its brachial face is covered with cartilage in a triangular space ; its radial fixee is straight and plane, and is every where covered with cartilage ; most of the digital face is a little concave, and also mostly covered with cartilage ; lastly, the palmar face is rough and slightly concave in its inner half ; its outer half is straight and covered with cartilage.

§ 698. Its ossification advances equally with that of the two preceding.

§ 699. It articulates by the cartilaginous pol-tion of its brachial face with the triangular intermediate cartilage, by its radial face with the semilunar bone (§696), by its digital face with the unciform bone(§714), and by the cartilaginous part of the palmar face with the pisiform bone (§ 700).

IV. OF THE PISIFORM BONE.

§ 700. T\\q pisiform bone {os pisiforme, articulare, subrolundnm) is the smallest bone in the wrjist. Its form is rounded and oblong, and it is situated entirely above the palinar face of the other bones in the posterior range, which are almost all on the same level except the anterior part of the scaphoid bone, which also projects considerably into the palm of the hand. The dorsal face of this bone is straight and covered with cartilage, and is the articulating surface, uniting it with the pyramidal bone (§ 699). It does not begin to ossify till after the age of six years. It forms with the scaphoid bone (§ 690) the upper eminences of the carpus.

II. OF THE BONES OF THE SECOND, THE INFERIOR OR ANTERIOR, CARPAL RANGE.

§ 701. The second carpal range includes the largest and most irregular bones of this region. The first three bones of the upper range, however, are larger than the two anterior of the second. The bones of the latter, counting from before backward, are the trapezium, the trapezoides, the os magnum, and the os unciforme.

I. OF THE TRAPEZIUM.

§ 702. The trapezium {os multangulum, majus trapezoides, trapezium, rhomboides) has a very irregular quadrilateral form. Its quadrilateral, transverse, brachial face is divided by a sharp ridge, which extends from the palm of the hand to the palmar edge, into two slightly concave surfaces, having the form of an irregular square, situated one at the side of the other, and covered with cartilage. The digital edge is transverse, concave from behind forward, slightly convex from the back of the hand to the palm, and also covered with cartilage. The dorsal, palmar, and radial faces are very uneven and rough.

§ 703. This bone is still entirely cartilaginous at the age of six years.

§ 704. It articulates by the anterior part of its brachial face with the scaphoid bone (§ 693), by the posterior with the trapezoides (§ 706), by its ulnar face with the metacarpal bone of the index finger, by the digital face with the metacarpal bone of the thumb.

II. OF THE TRAPEZOIDES.

§ 705. The trapezoides {os multangulum, s. trapezium minus, s. pyramidale) represents a short and irregular pyramid, the base of which is toward the back of the hand and the summit toward the palm. The dorsal and palmar faces are rough, destitute of cartilage, and slightly concave.

§ 706. Ossification always begins in it later than in the trapezium.

§ 707. It articulates by its brachial face, which is but slightly concave, with the scaphoid bone (§ 693) ; by the radial edge which is a little convex, with the trapezium (§ 704) ; by its digital face, which is triangular, convex from before backward, and concave from above downward, with the metacarpal bone of the index finger, and by its convex ulnar face with the os magnum (§ 710).

III. OF THE os MAGNUM.

§ 708. The os magnum {os magnum s. capitatum) is the largest of the carpal bones. Its form is pyramidal, and it is so situated that its greatest diameter extends from its brachial to its digital face, the latter representing its base and the former its summit. Its brachial face is covered with cartilage, is rounded, and very convex. Its radial face is also covered with cartilage, and divided by two eminences, which extend from the back of the hand to the palm, into three parts, of which the posterior, larger than the other two, is convex and rounded ; the central is also a little convex and square ; finally, the anterior, the highest, is concave. The anterior face is triangular and a little concave and is also covered with cartilage. The ulnar face is i^ugh in its anterior part, and its posterior is almost straight and covered with cartilage. The dorsal and palmar faces are slightly concave and have no cartilage.

§ 709. In the full grown fetus this bone is ossified in its centre, but not very perceptibly ; most of it is cartilage. Its ossification is not completed till the tenth year.

§ 710. It articulates by its brachial face with the semilunar bone (§ 696), by Uie upper part of its radial face with the scaphoid bone (§ 693), by its central portion with the trapezoides (§ 707), by its anterior face with the metacarpal bone of the third finger, by the cartilaginous portion of its ulnar face with the os unciforme (§ 714).

§ 711. A ninth carpal bone sometimes exists between this bone and the preceding,(l) a curious analogy with the formation of apes, in which we find, between the trapezium and the os magnum, a ninth bone, which seems to arise from the division of the trapezoides into two portions.

IV. OF THE 03 UNCIFORME.

§ 712. The unciform bone (os hamatum, s. os unciforme) has an irregular triangular form, the base being turned toward the back of the hand and the summit toward the palm. The latter portion, which is flat from one side to the other, forms the hook. The unciform process causes this bone to project very much inward beyond the central two, as the trapezium does outward, and produces, with the latter, the inferior eminences of the carpus, winch, united to the superior (§ 700), foiin the walls of a groove, through which pass the tendons of the flexor muscles of the hand and fingers.

(1) Salzmanu, Uccas.obs. illastr. anaL, Strasburg, 1725, p. 3.

The brachial face of the unciform bone is covered with cartilage, and is oblique, convex, and oblong. The external portion of the radial face is plain, and covered with cartilage ; the internal is rough. The digital faces are slightly concave fi'om without inward, a little convex from before backward, and divided by a slight ridge, which extends from the unciform process to the palmar side, into a small anterior and a larger posterior portion. The dorsal face is a little convex and rough. The palmar firce, which is almost destitute of cartilage, is continuous by its external edge with the unciform process.

§ 713. We discover also in this bone, in the full grown fetus, an osseous nucleus, situated near the centre, larger than that of the os magnum, although the unciform bone itself is smaller than this bone. Ossification is completed at the same time as in the preceding bone.(l)

§ 714. The unciform bone articulates by its brachial face with the pyramidal bone (§ 699), by its radial portion with the os magnum (§ 710), by its digital portion with the metacarpal bones of the fourth and fifth fingers.

II. OF THE METACARPAL BONES.

§ 715. The metacarpus is composed of five cylindrical bones, which vary in length, but are all formed after the same model. The bodies are rounded, or slightly triangular, convex on the dorsal side, concave on the palmar face, and a little broader toward the anterior end than near the posterior extremity. We distinguish in them three faces and three edges, which, except in the first metacarpal bone, in the anterior and posterior halves are situated differently. In fact the anterior or inferior portion presents a dorsal, a radial, and an ulnar face ; also an internal, inferior, or palmar edge, a radial, and an ulnar edge, of which the first is more prominent. The posterior or upper half, on the contrary, presents two lateral faces, but not a superior, which is replaced by an inferior or palmar face ;^o palmar edge, but a dorsal, external, or upper edge ; because the t* lateral edges unite at the central part of the bone, and after leaving this point, a. sham edge extends on the back of the latter to its poster ior extremity.

The posterior extremity or the base {basis) is triangular or irreâ– gularly quadrangular, and covered with cartilage at its posterior portion, which is generally plain. The lateral parts are also mostly covered with cartilage. Before and between the cartilaginous points of the lateral faces, are very considerable rough depressions, which are succeeded by similar projecting eminences . these are the vestiges of the connections of the metacarpal bones with each other and with those of the carpus, in such a manner as to admit of but very slight motion on account of the arrangement of their articular surfaces, of the number of means of union, and of the substance which forms them.

(1) Albinas, followed by all the anatomists, says : “ Singulacarpi ossa cartilaginea in fÅ“tu sunt, nee nisidiu post nativitatem osinchoantf' which is incorrect, according to our numerous examinations of full grown fetal skeletons. We always find nuclei of bone in the semilunar and unciform bones: they are more imperfect than those of the tarsal bones, proportionally smaller, and not infiltrated with blood, but yellowish.

The anterior extremity is rounded, almost entirely covered with cartilage, and from its form is called the head (capitulum). It is a little compressed from one side to the other, and terminates backward on each side, both on the dorsal and palmar faces by two tubercles {tubercula), between which, on each side, is a large depression (sinus). These depressions and tubercles trace the insertion of the ligaments.

§ 716. Ossification of the metacarpal bones commences at the third month of pregnancy. They do not all appear at once : we see the second, then the third, and then the others appear. Towards the end of the third month each contains an oblong nucleus of bone. In the full-grown fetus, the body' only is ossified, and the two extremities are still entirely cartilaginous. They do not begin to ossify till very late ; we see only one nucleus of bone in the head towards the end of the second year. This nucleus remains separate from the body for a long time, sometimes until the subject is fully grown. We have never seen it in the posterior extremity, except in the metacarpal bone of the thumb, which seems to have none in its head, at least we have never been able to see it in this part. The posterior or upper nucleus of the fii'st metacarpal bone remains separated from the body as long as the anterior nuclei in the other four.

§ 717. The metacarpal bones articulate by their posterior cartilaginous faces, with the anterior range of the carpal bones: by the cartilaginous parts of the lateral wall of their bases, partly with these bones, and partly with each other ; by their heads with the corresponding bones of the posterior phalanges.

I. OF THE FIRST METACARPAL BONE.

§ 718. The first bone of the metacarpus, or the metacarpal bone of the thumb (os metacarpi pollicis), varies from the others in size and in form. It is much shorter, but thic^r and broader than the others, and relatively and absolutely flatter, wile the latter are compressed, that is, are narrower from one side to the other, than from above downward. The dorsal face, the broadest of all, extends the whole length of the bone. The two lateral faces, of which the ulnar is the most extensive, unite at an angle much more obtuse than in the other metacarpal bones. The base is more broad than high, and has no cartilage on its two sides. Its posterior face is covered with cartilage, slightly concave from the radial to the ulnar side, a little convex from the dorsal to the palmar face, open on the two sides, and bounded only upward and downward by a slight projection. These particulars, and the extreme looseness of the capsular ligament, allow this bone much more motion than the other bones of the metacarpus. The head also is broader, but lower than in the others.

§ 719. The first metacarpal bone is one of those which is developed the last. In the fifth month of pregnancy, it is still, in proportion to the others, much shorter than it is afterward, since it is not more than one half shorter than the fifth, which, when the body is perfectly developed is only one-seventh longer. Its mode of ossification differs from that of the others in a peculiarity mentioned above (§ 716).

§ 720. This bone articulates with the trapezium (§ 704).

II. OF THE SECOND METACARPAL BONE.

§ 721. The second bone of the metacarpus, or the metacarpal bone of the index finger, is generally the longest of all, and extends backward farther than the others. The next one is seldom as long : the second is thinner than the third. Its posterior extremity has a triangular articular face mostly faced with cartilage, which is very concave, and corresponds exactly to the convex digital face of the trapezoides (§ 707). On its radial face upward and backward, is a small plain cartilaginous surface. The ulnar face has another which is larger, occupying all the height of the bone, and divided by a slight projection into a smaller posterior portion, and an anterior part which is larger. This bone articulates by the cartilaginous part of its radial face, with the trapezium ; by the posterior part of that of its ulnar face with the os magnum (§ 710) ; and by the anterior part with the third metacarpal bone.

III. OF THE THIRD METACARPAL BONE.

§ 722. The third bone of the metacarpus articulates with the os magnum (§710) by its posterior face, which is irregularly quadrilateral, broader above than below, convex from above downward, and covered with cartilage ; with the second metacarpal bone, by the radial face of its base, which is covered with cartilage at its posterior part ; finally, with the fourth, by two flattened cartilaginous surfaces, situated one above the other, as is seen in the ulnar side of the same part.

IV. OF THE FOURTH METACARPAL BONE.

§ 723. The fourth bone of the metacarpus is much shorter and thinner than the third. Its posterior articular surface is narrow, irregularly quadrilateral, straight, and covered with cartilage, and corresponds to the anterior portion of the digital face of the unciform bone. Two small plane surfaces, which are covered with cartilage, and situated one above the other on the radial side of the base, are fitted to the corresponding surfaces of the ulnar side of the third metacarpal bone (§ 722). Another narrow surface, extending as high as the bone, is found on the ulnar side, and corresponds to a similar one on the radial side of the fifth metacarpal bone (§ 724).

V. OF TIIF, FIFTH METACARFAL BONE.

§ 724. The fifth metacarpal bone, is shorter, but thicker than the fourth. The articular face of its posterior extremity is quadrangular, convex, and covered with cartilage, and articulates with the anterior portion of the unciform bone. It articulates, by a small cartilaginous portion of its radial face, with the ulnar face of the fourth metacarpal bone (§ 723). The upper articular face presents, on the ulnar side, a blunt and rough tubercle.

Iir. OF THK BONES OF THE FINGERS.

§ 725. Thefingers contain fourteen bones; each one,exceptthe thumb, has ihTeephalanges(phalanges,articnli,internodia). All thebonesof the fingers are elongated, flattened from their dorsal to their palmar face ; consequently more broad than high, convex from before backward on their dorsal face, concave on their palmar face, broader and stronger at their posterior than at their anterior extremity ; and presenting, at least in the former, a slightly concave and cartilaginous articular surface.

§ 726. Ossification begins in the bodies of these bones later than in the metacarpal bones, and not until towards the end of the third month of pregnancy. The osseous nuclei of the first and third phalanges appear before those of the second. All these bones are developed by two points of ossification only ; a larger for the body, and the other for the posterior extremity. This last begins to ossify about the age of five years ; it remains separated from the body a long time, often even until the subject is perfectly developed. No special nucleus of bone exists in the anterior extremity.(l)

I. OF THE PHALANGES OF THE FIRST RANGE.

§ 727. The phalanges of the first range are the longest and strongest. The dorsal face of their bodies is very convex from one side to the other ; the interior or palmar face is less so, but presents, in its centre, especially in the bones of the three middle fingers, a radial and an ulnar edge, which project very muc^r into the centre of the hand, and are turned upon, themselves. This projection is seen only in the first phalanx of the thumb. The posterior extremity presents a rounded articular process which is almost jilain and covered with cartilage, and which articulates by arthrodia with the heads of the metacarpal bones. On the lateral parts, and below them, is on each side a very projecting edge. The upper face is rounded and triangular, and covered with cartilage, having in its centre a longitudinal furrow which gives it the form of a pulley. On each side we observe a depression {sinus), behind which is a slight tuberosity.

(1) Albinus says that the two piece,? of bone fuse tlirectly with each other. {Ic. oss. foet., p. 120.) We have never observed a fact to support tin's proposition. Loder is likewise mistaken (Anatomie, p. 264) in saying' that the anterior extremity also develops itself by a single osseous germ. Albinus bad alrcad)' given a correct description of the progress of ossification.

Of these five bones that of the middle finger is the longest ; those of the second and fourth fingers are nearly equal in length, and so too of the first and fifth ; the latter however is a little longer than the other. That of the thumb is proportionally the broadest and flattest, which serves to distinguish it from that of the little finger.

XI. OF THE BONES OF THE SECOND PHALANX.

§ 728. The bones in the second phalanx very much resemble those in the first, but they are flatter and broader in proportion to their length, especially in their posterior portion. The edges project very much in the central part of the second, third, and fourth, but less so than in the first phalanx. The posterior articular face fits into the pulley of the first phalanx ; it is also divided by a projecting line into two small and slightly concave lateral facets ; the interior has sbghtly the form of a pulley. In this range of bones that of the middle finger is the longest and the sti'ongest ; next come those of the fourth and second fingers, the shortest is that of the fifth finger.

III. OF THE BONES OF THE THIRD PHALANX.

§ 729. The third phalanx differs from the others, as its bones present an articular surface faced with cartilage only in their posterior parts. This face is much broader in proportion than their anterior extremity. The latter is less bulging, rough, rounded, and terminated by a tubercular edge. Besides, the bones in the third phalanx are much shorter than those of the other two ranges. Their posterior face is concave, and by a slight edge hollowed into two lateral cavities.

The upper face is smooth, the inferior very rough, especially near the extremities. The phalangÅ“al bone of the thumb in this range is much longer and thicker than the rest, which are smaller and nearlj^ equal ^ in length, but of different thicknesses ; that of the little finger is much smaller than the rest.

B. OF THE ANOMALIES IN THE BONES OF THE HAND.

§ 730. The bones of the hand are sometimes partly or wholly deficient, which results from an imperfect development. In the formercase, there are sometimes whole parts of which we can discover no traces, sometimes only portions of these parts are deficient, as for instance one or several bones of the phalanges.

So too the number of the bones is sometimes increased by one or more ; this increase takes place in the number of the fingers, or of the other parts of the hand.

Sometimes the bones of two or more fingers are fused together.

A disease, which does not belong exclusively to the bones of the fingers, but which very often attacks them, is a swelling, with a dimiution in the density of their substance. This disease results from inflammation, and is called pœdarthrocase, because observed most fre» quently in children, particularly those whose constitutions are feeble.

CHAPTER II. OF THE BONES OF THE LOWER EXTREMITIES.

ARTICLE FIRST.

OF THE ILIAC BONES.

A. GENERAL REMARKS ON THE ILIAC BONES.

§ 731. The iliac or coxal bones {ossa coxartm, s. pelvis lateralia, s. innominaia) correspond in form and situation to the shoulder-bones of the upper extremity. 1st. In form ; being composed generally of two parts, one elongated and smaller, the other broader and larger. 2d. In their situation ; they are placed between the abdominal extremities and the lower part of the vertebral column, in the same manner as the bones of the shoulder are, between the second section of the pectoral limbs and the upper part of the vertebral column ; their broad portion is situated backward and on the side, and their long portion forward, where the bones of the two sides meet, while the arrangement in the posterior face of the trunk is different. Comparative anatomy and the history of ossification place this analogy in a still stronger light.

§ 732. The iliac bone is divided into three parts, the ilium (os ilium), the ischium (os ischii), and the pubis (os pubis).

I. OF THE ILIUM.

§ 733. The ilium is the largest of these three portions. It corresponds to the scapula since it constitutes the broadest, the most posterior and the most superior part of the whole bone. Its form is irregular, more however like a triangle than any other figure. Its upper edge is convex ; the anterior is usually straight and is grooved below ; it is continuous with the ischium and the pubis by the anterior part of the latter.

§ 734. The upper convex edge is the largest and the broadest, especially forward and backward. It is called, from its form, the crest of the ilium (crista ossis ilii). We distinguish in it an external and an internal lip, and a middle portion. It terminates forward by a small eminence which projects above the anterior edge, and is called the anterior and superior iliac spine (spina ossis ilii anterior superior)', backward,by two other projections, called the upper and lower posterior iliac spines, which are separated from each other by a small semi-lunar notch (incisura stmi-lunaris) .

The anterior edge, oblique from above downward, and from behind forward, presents two superficial notches which are separated by an eminence, the anterior and inferior iliac spine [spina anterior inferior ) .

In the inferior edge is a large notch ; it forms the posterior and superior part of the iliac notch [incisura iliaca, s. ilica superior).

§ 735. The external and the internal faces are slightly concave, because the bone becomes thicker at its circumference ; the internal however is more concave than the other. The upper part of the inner face is smooth, the posterior and inferior is very rough. The anterior and smaller portion of this rough part is faced with cartilage, elongated, convex forward and concave backward ; it is called the auricular surface [facies auricularis) . The posterior is more uneven and is destitute of cartilage.

The lower and by far the smallest part of the plane portion of this face, curves on the upper at an obtuse angle, and follows an almost perpendicular direction, while the upper extends obliquely from above downward and from without inward.

The angle which separates them forms, at the posterior part both upward and downward, between the smooth and the rough portions of the internal face, the curved line [linea arcuata). It is continuous forward with the posterior and projecting edge of the upper face of the horizontal branch of the pubis, thus producing all around the iliac bone a ridge, called the linea innominatn. Immediately above this crest is found a large foramen through which the artery of nutrition passes to the bone.

The external face is smooth in every part, and divided by two semicircular fines, which project slightly, being concave upward and backward, into two portions, the anterior of which is much greater than the posterior.

§ 736. The ilium is thickest downward and forward, where the inferior and anterior edges meet ; forward and outward it presents a deep fissure, which forms the upper and external smaller portion of the cotyloid cavity [acetabulum). Some anatomists term this part of the bone the body.

II. OF THE ISCHIUM.

§ 737. The ischium [os ischii) forms the inferior central part of the iliac bone. It descends almost perpendicularly from the anterior part of the lower edge of the latter, but goes however a little from above downward and from without inward, following the same direction as the lower part of the internal face of the ilium. In this place its inter nal face is slightly convex backward and very concave forward. The upper part is the broadest and thickest, and has also been called the body. The anterior portion of its external face forms the larger and lower part of the cotyloid cavity.

The posterior edge of the body is sharp ; it forms the anterior part of the iliac notch, and runs backward and inward into the sciatic spine [spina ossis ischii).

The descending branch {ramus descendens) begins in this place. '^I'his branch is slightly compressed, but is very thick, and swells downward into the sciatic tuberosity {ttiber ischiadicum), which is covered with cartilage. A deep furrow is found externally between this tuberosity and the lower edge of the cotyloid cavity. We remark also between it and the spine, on the internal face and posterior edge, the inferior iliac or isckiatic notch (incisura iliaca inferior, s. ischiudica).

The ascending branch leaves the tubercle, and goes inward, forward and upward. This branch is much shorter and weaker than the descending, and is compressed from before backward and from without inward.

HI. OE' THE PUBIS.

§ 738. The pubis (os pubis, s. pectinis) resembles the ischium in form, being also composed of two branches united at an angle. The upper or horizontal branch (ramus horizontedis) begins with the bulging external extremity of the body, by means of which it forms the upper and internal part of the cotyloid cavity ; and then contracting, it also forms in its centre and at its origin a triangle. Toward its inferior extremity, it becomes considerably broad from within outward, becomes thinner from before backward, and thus produces its descending branch (ramus descendens), which goes dowmward and outward, gradually becomes narrow, and finally unites with the ascending branch of the ischium.

The inferior face of the horizontal branch is concave from behind forward and from without inward. The anterior edge, situated between the upper and anterior faces, is blunt. The upper, placed between the posterior and superior faces, forms the crest of the pubis (pecten, s. crista). Both unite, beyond the internal extremity of the horizontal branch and on the anterior face, in the tubercle of the pubis (tubercnlum ossis pubis).

§ 739. d'he ischium and the pubis united repres4nt an irregular ring, which surrounds an opening, closed in great part by a membrane, and called \ho, obturator ox oval foramen (foramen obtnratorium,s. ovale). 'I'his foramen is, however, triangular or irregularly quadrilateral. It has an external, an upper, and an internal edge.

The external edge, formed by the inner edge of the descending branch of the ischium and the outer part of the horizontal branch of the pubis, is longest, and is often divided into two portions, an inferior, which is the smaller, and a superior. The upper part is always very broad, and forms a channel, the direction of which is from without inward and from behind forward, through which the obturator nerves and vessels pass from the pelvis. The abdominal viscera sometimes pass out through this opening, forming a hernia through the foramen ovale.

The upper edge, which is oblique from above downward, from behind forward, and from without inward, is formed by the inferior edge of all the inner part of the horizontal branch of the pubis, and unites at an obtuse angle with the internal.

The latter, oblique from above downward and from without inward, is formed by the upper edge of the descending branch of the pubis and of the ascending branch of the ischium, and it unites at an acute angle with the external.

§ 740. The cotyloid cavity {acetahidum) is situated on the external face of the iliac bone, in the place where the three pieces which form it meet. Its largest inferior portion is formed by the body of the ischium, its smallest anterior portion by that of the pubis, and its posterior part by that of the ilium, that is, by the thickest portion of the iliac bone. It is round, rather deep, and surrounded by a sharp edge {supercilium ace^ tabuli), which presents forward and downward, toward the foramen ovale, a considerable space, called the cotyloid Jissure {incisura acetabidi). Its central and anterior part, the sinus {fovea), terminates anteriorly by a notch, and is uneven and rough, is grooved in several places, particularly in the upper and anterior region, and is destitute of cartilage. The upper and posterior, on the contrary, which is called the semilunar face {facies lunata), is smooth and covered with cartilage ; it extends forward, and forms two horns {cornua) which sun'ound the notch, so that the superior does not always descend entirely to it< The inferior is much more prominent, and forms with it a channel.

§ 741. The iliac bone is developed by three nuclei of ossification, which correspond exactly to the three parts we have described. These three parts are not however formed at the same time. First, the nucleus of the ilium appears in the fourth month, next that of the ischium and lastly that of the pubis. Those parts which are most distant from the median line and from the anterior face are always developed first ; eo that they enlarge from without toward the median line. In the full grown fetus, these three pieces are not only entirely distinct, but the ascending branch of the ischium and the descending brairch of the pubis are but shghtly ossified ; so that there is more than half an inch of cartilage between them. At two years of age they touch, but the cartilage exists till the seventh year. About this period they unite with one another, although the three pieces of the iliac bone are still perfectly distinct, in the cotyloid cavity, in subjects of fourteen years of age. In the sixteenth year there is developed, in the cartilage which joins them in this place, a bone formed like a Y, which unites with the rest to form but a single bone. The formation however is not yet completed ; for afterward, a single oblong nucleus of bone appears in the crest of the ilium, and a second along the inferior edge of the ischium. These do not unite till the age of twenty, and it is then only that the iliac bone is perfectly developed.

§ 742. The iliac bones articulate with the sacrum, with the coccyx, and with each other ; viz. the ilium by its auricular surface and the rough portion behind it, with the sacrum, by synchondrosis ; the ischium, with the sacrum the coccyx, and ilium by the two sacro-sciatic ligaments ; the two descending branches of the pubis articulate together at their upper part by the intermediate fibro-cartilage.

§ 743. From tho description given, the iliac bone differs from the scapula in certain respects ; but the analogy is greater than the differences, and the. latter may be easily explained (§731). In the imperfect state the analogy is more stiiking, as is always the case ; the broad part and the thin part do not make one, as in the adult, but they are separated ; and it is still more remarkable in this respect, that although the pubis and the ischium form after the ilium, they however unite with each other before they join the last ; so that taken together they represent the clavicle. Although the clavicle develops itself before the scapula, while the ischium and the pubis are formed after the ilium, yet this difference is of little importance. So too the difference in the manner in which these bones are articidated with each other and with the vertebral column, as also in the form of this articulation, which always continues, does not deserve notice.(l)

If we place a scapula and an iliac bone side by side, so that the internal edge of the former and the crest of the latter are directed upward, we recognise, without difficulty, that the inner, the anterior, and the outer edges of the scapula correspond to the crest, to the anterior edge, and to the iliac notch of the iliac bone ; the glenoid cavity of the former, to the cotyloid cavity of the latter ; the coracoid process, to the body of the pubis : finally, the spine of the scapida, to the body and descending branch of the ischium ; the rest of the pubis and of the ischium represents the clavicle.

The horizontal portion of the pubis may also correspond to the clavicle, and the descending branch of the ischium to the coracoid process ; since the ascending branch of the latter and the descending branch of the pubis are the costal cartilages ossified, and the fibrocartilaginous mass between the descending branches of the pubis may be compared to the sternum in its unossified state.

B. OF THE ILJAC BONES ARTICULATED WITH EACH OTHER AND WITH THE LOWER BONES OF THE TRUNK, OR OF THE PELVIS.

I. NORMAL STATE.

§ 744. The pelvis{\) is a bony cavity situated at the lower extremity, forming a part of the trunk, and it is composed of the sacrum (§ 491), and the coccyx which form it posteriorly, and by the two iliac bones (§ 731), which circumscribe it in the rest of its extent. The form of this cavity is very irregular, being much broader from one side to the other than from before backward, while it is much higher on the sides and backward than it is forward.

(1) See on this subject our Beylrœge, vol. ii. p. 2. Comparative anatomy also demonstrates how unimportant is this difference.

(2) Ed. Sandifort, De jiclvi cjusque in jmriu dilataLione diss., Leyden, 17.53. — J. Ripping-, Diss. sys. quasdam. depcLvi animadversiones, Leyden, 1776. — C. C. Creve, Vom Baue des weiblichen Bechens, Leipsick, 1794. — J. .1. Watt, Analomico-chirurgicalview of the male and female pelvis, London, 1817. — G. Termanini, Della figura, ampiezza, altezza, situazione cd osse della caviia del pclvi, in Opusculi. scient, di Bologna, vol. i. 1817.

§ 745. It is dmded into the large and iq^per pelvis, and the small or loiver jjelins. The large pelvis is the space circumscribed on both sides bj the upper part of the iliac bones, backward by the upper face of the sacrum, and forward by the upper edge of the pubis, so that it is open forward and downward. It is separated from the lower pelvis by the linea innoininata, or more properly the tinea terminalis, the terminal, marginal, or peripheric line, which follows the anterior edge of the upper face of the sacrum, and by the promontory (§ 495), the boundary between the upper and lower parts of the iliac bones, and by the crest of the pubis. The surface comprised by this line is called the upper opening OÏ strait of the small pelvis [introituss.apertura pelvis superior). The large pelvis is much broader across than from above downward, or from before backward, especially at its upper opening ; for after leaving this point, its lateral walls which are shghtly concave, proceed obliquely downward and inward towards the inferior opening.

We distinguish in the large pelvis an anterior and a posterior transverse diameter {diameter transversa posterior et anterior), indicating the first, the greatest distance between the two iliac crests, and the second, the distance between the anterior and posterior ihac spines.

§ 746. The small or lower j^elvis is more rounded and more elevated than the large. Although broader from one side to the other than in any other dhection, it is however much narrower than the latter ; more surrounded than it by bony walls in all its circumference. Its walls are formed by the greater part of the sacrum, of the coccyx, of the ischia, and the pubes and the lower part of the ilia. The hollows in the walls of the small pelvis are filled by muscles and ligaments.

We observein the small pelvis, the entrance or superior strait (§ 745), the outlet or inferior strait {exitus, s. apertura inferior), and the cavity {cavum), the space comprised between the two straits.

The upper strait has a rounded and oblong or elliptical form, and has a small process forward at its central part. We distinguish in it four diameters, an antero-posterior or sacropubic, the conjugate diameter {diameter antero-posterior), which is measured from the centre of the promontory to the centre of the symphysis pubis ; the transverse or iliac { D. transversa), which extends from one side to the other, falling on the centre of the two sides of the linea innominata; the two oblique diameters { D. obliquÅ“,s. diagonales), which extend from the sacro-iliac symphysis of one side to the union of the pubis and ihum of the opposite side, and are distinguished into right and left. The oblique and transverse diameters are longer than the conjugate diameter.

The walls of the cavity of the pelvis are a little oblique from above downward. We distinguish in this cavity a straight diameter, a transverse and two oblique diameters. The first reaches from the union of the second and third sacral vertebræ to the centre of the symphysis pubis. The transverse diameter extends from the centre of one cotyloid cavity to the same point in the opposite cotyloid cavity. The oblique is measured from the inferior extremity of the sacro-iliac symphysis to the centre of the foramen ovale of the opixisite side : they are the longest, and the straight diameter is longer than the transverse.

The inferior strait, or the outlet, is narrower than the other regions, but it can enlarge an inch, as the bones of the coccyx are movable. It is formed by the lower edge of the eoccyx, the two sacro-sciatic ligaments, the ascending branch of the ischium and the descending branch of the pubis ; so that is composed of three large arches, viz. two lateral, situated between the coccyx and the sciatic tuberosities, and an anterior, which is larger, and is found between the two latter tuberosities. We distinguish in it only two diameters, a straight and a transverse. The straight or cocci-pubic diameter extends from the centre of the lower extremity of the coccyx to that of the lower edge of the symphysis pubis ; the second or ischiatic, is measured from the centre of the lower edge of one sciatic tuberosity to the corresponding point of the other. When the coccyx is pushed back the straight diameter increases in breadth, so that it becomes greater than the transverse ; but otherwise, in the normal state, they are equally long.

Besides these imaginary lines, we admit also an axis (axis, lima directionis pelvis), ( 1 ) that is, a line passing through the centre of the pelvis from above downward, but which, from the irregular form of this cavity, is not exactly parallel to its walls. This line is convex backward, and concave forward. We may suppose it produced by two or three straight lines, which unite at an obtuse angle in the centre of the straight diameter of the cavity of the pelvis ; the upper line is the axis of the superior strait, the lower, that of the inferior strait, and the central one, of the cavity of the pelvis. They are directed, the first from above downward, and from before backward ; the other two from before backward, and from behind forward.

The axis of the pelvis has not the same direction as that of the body, and the angle it forms with this last is not the same in all its extent, for this angle gradually contracts from above downward ; so that it may be estimated about thirty degrees upward, twenty-five in the centre, and eighteen downward.

The surface, near the centre of which these lines are supposed to pass, is called the surface of inclination ; and the difference between the direction of the pelvis and that of the trunk is termed the inclijiation (inclinatio) of the pelvis.(2)

§ 747. The pelvis is undoubtedly that part of the body which varies the most in the two sexes on account of its relations with the function of generation. The differences it offers in this respect, are then very important, and deserve to be examined particularly.

The general characters of the female pelvis are its breadth and depth ; those of the male pelvis are its narrowness and height.

The lateral walls, of the superior pelvis in the female have a more oblique direction downward : they are less deeply grooved from before backward, or from above downward, separate very much from behind forward, and are much broader in this direction than in the male, which makes them appear lower.

(1) J. G. Rcedercr, Dc axi pelvis programma, Gottingen, 1751. — Sommer, Dei Axe des weiblichen Beckens, Brunswick, 1781.

(2) G. G. Stein, De pelvis süu ejusque indinalione diss., Marburg, 1797.

The small pelvis is more spacious, less elevated, and more uniformly broad, than in the male, especially in the transverse direction. The circumference of the female pelvis is more rounded and elliptical, while in the male it is heart-shaped, because its walls fust separate a littlé from each other from behind forward, they then converge and approach insensibly, before uniting forward. The upper part of the sacrum in the male projects much more inward than in the female, a difference depending principally on what is observed in the form of this bon^ (§ 496) and on the greater breadth of the central part of the pubis ih the female.

In the female the iliac bones where their upper and lower portions unite, project very much beyond the sacro-iliac symphysis, while in the male they go almost directly forward. In the female the horizontal portion of the pubis extends almost in a straight line from without inward, after lea\ing the anterior edge of the cotyloid cavity ; instead of which, in the male, it goes directly forward. Hence it follows that the superior strait of the small pelvis in the female is broader, and its transverse and oblique diameters particularly are proportionally larger than the straight chameter.

The small pelvis has nearly the same breadth in every part in the female ; that of the male, on the contrary, becomes much narrower from above downward, because in the female pelvis tire ilium and the ischium descend almost in a straight line, while in the male they approach each other very much while descending ; and also because the sacrum is much straighter in the female, not projecting so far backward m its centre, nor so much inward in its lower portion ; hence the sciatic tuberosities are much nearer each other in the male.

In the same manner, these bones and the pubis, and consequently all the small pelvis in the male is much higher than in the female.

The foramen ovale is much higher and narrower in the male, less elevated and broader in the female ; it is more oval in the former and more triangular in the latter.

Finally, the outlet in the male is mutch narrower than in the female. The distance between the two sciatic tuberosities being much greater, the ascending branches of the ischia and the descending branches of the pubes meet in the female only after describing a large arch {arcus ossium jnibis), while they unite at an acute angle {angulus ossium pubis) in the male. Besides in the male the descending branches of the pubes are turned, so that one of their faces looks, more forward and the other more backward, while in the female the arch they describe causes their anterior face to look more outward and the posterior more inward, an arrangement which renders the difference in the form of the inferior strait still more evident. Thirdly, the branches of the pubes being much thinner in the female, the inferior strait of the pelvis is broader,

The most essential cUfFerence then between the male pelvis and that of the female in respect to breadth and form arises principally from the lower strait, which in the male is not only narrower but also heartshaped and terminated forward in a point, while in the female it is rounder.

§ 748. The important differences in the form and breadth of the pelvis in the two sexes will be more evident from a table of the comparative measurements of the diameters of the cavity of the pelvis, taken from subjects of the same height.(l)

MALE

1

FEMALE

PELVIS.

PELVIS.

Transverse diameter of the large pelvis.

inches. lines.

inches.

lines.

1st. Between the anterior and Buperior iliac spines

7

8

8

G

2d. Greatest distance

8

3

9

4

Transverse

diameter

1

4

G

5

0

Oblique

do.

1

[• of the superior strait . . .

4

5

4

5

Straight

do.

J

4

0

4

4

Transverse

do.

1

4

0

4

8

Oblique

do.

1 of the cavity

5

0

5

4

Straight

do.

J

5

0

4

8

Anterior transverse diameter 1

3

0

4

5

Posterior

do.

do. (- of the outlet . . .

3

U

4

6

Straight

do.

do. J

3

3

4 4

and sometimes 5 in.

II. OF THE ANOMALIES OF THE PELVIS.

§ 749. The anomalies peculiar to the female pelvis (2) arc principally deviations of formation, which are congenital or accidental, and which affect the bones themselves, or their connections. All these deviations are very important as they exert a pernicious influence upon the functions of generation, especially upon parturition.

§ 750. 1st. The anomalies of these bones are seen in the variations presented in their form and situation, or in their continuity.

a. Anomalies in form. The slightest abberration consists generally in an increase or a diminution of capacity.^ which causes a general largeness or narrowness of the pelvis. These two states however, more particularly the second, when existing in a certain extent, are more rare than anomahes in the form of one or more hones, whence the figure of the whole pelvis varies more or less from the ordinary proportions either because only one of these regions is deformed, or because, even when the anomaly extends to the whole pelvis, a single diameter is shortened, so that the cavity is contracted in only one dhection. These different kinds of anomalies are by no means equally common.

(1) The calculations forming" the basis of this table differ a little from those of Chaussier. See Mad. Boivin, Mem dc Vart des accouchemens, p. 26-29.

(2) C. C. Creve, Von den Krankheilen des weiblichen Deekens, Berlin, 1795. — Mad. Boivin, Mém. de Vart des accouch. p. 31-34.

Most usually the antero-posterior or conjugate diameter of the tipper and lower opening of the pelvis is narrower, because the sacrum describes too great a curve, whence its upper and lower extremities irroject too much iuward. At the same time the pelvis is almost always oblique, which renders the oblique diameters unequal. The transverse diameter generally preserves its proper proportions, but is sometimes unusually broad. As to the straight diameter of the cavity,it is often unusually and uselessly long, from the great concavity of the sacrum.

The shortening of this straight diameter however may result also from an anomaly in the form of the iliac bones, they being either too short, or because, although large as usual, they describe an arch which is too convex.

The effect is the same also when the pubes are not properly arched externally, but go directly inward after leaving the ilium. A narrow space is then formed forward which does not assist the passage of the fetus, although the straight diameters are not really shortened.

Sometimes only the conjugate diameter of the outlet of the pelvis is shortened by the ossificatiorr of the ligaments of the coccyx. The shortening of the transverse diameter of the superior strait is rare, but that of the inferior strait, especially backward, is common, from the bending inward of the sciatic tuberosities.

Curvatures of the vertebral column, although extensive, have no effect upon the form of the pelvis, when not resulting from a general disease, as particularly rachitis. We have satisfied ourselves of this by a careful examination of a great marry skeletons of hunch-backs.

b. Anomalies in situation. They cause a change in the direction or in the inclination of the pelvis. This cavity is inclined farther forward, arrd its distance fi'om the horizontal line is greater as its axis is more perpendicular. On the contrary, it slopes very much more backward, and is more obhque as its axis is more horizontal.

c. Anomalies in the contmuity of the hones. These consist in fractures which are not impossible as has sometimes been thought, but are observed in the pelvis even more frequently than in the other parts of the trunk. The part of the walls of the pelvis most frequently broken is the ilium, and the fracture is either transverse or longitudinal ; a fracture of the descending brarrch of the ischium is most unfrequent. The horizontal and descending branches of the pubis and the ascending branch of the ischium almost always break together. Fractures of the sacrum are for the most part transverse ; they are seldom seen except in the body of this bone.

§ 751. 2d. Anomalies in the arrangement of the connections of the bones of the pelvis consist in too loose or too firm a union.

a. Looseness in connection is primitive or accidental. The primitive is seen almost exclusively in the symphysis pubis. It is rarely met with alone,(l) and is most generally attended with an analogous anomaly in the bladder, a fissure of this organ. The bones are then always very imperfectly united by a fibrous ligament, which renders the gait unsteady, and the more as the pubes are generally separated some inches.

Accidental separation results either from external violence or disease, as inflammation and suppuration, by w'hich the ligaments are torn or destroyed. External violence fractures the bone sooner than it destroys the ligaments, excepting always the pieces of the coccyx, which are movably articulated with the sacrum and with each other.

b. Too great solidity of the connections, the fusion of the bones, is caused by the ossification of their fibro-cartilages or of their fibrous ligaments.

This is seen most frequently in the sacro-iliac articulation, especially in that ot the right side, which depends probably on the greater compression of this joint, from the support afforded to the body by the lower extremity of the right side.

It is less common to find a fusion either of a few, more particularly the lower of coccygœal bones, or of all, or finally of the first coccygœal bone with the sacrum. This anomaly is more frequent in males, especially equestrians, than in females.

The ossification of the sacro-sciatic ligaments is still more'rare. That of the symphysis pubis is still more so.(2) It generally but not always results from inflammation and destruction of the cartilage, while that of the other joints supervenes without inflammation, and solely from the gradual change of their proper substance, and of the fibrous tissues which surround them.

ARTICLE SECOND, OF THE FEMUR.

§ 752. The/cwi«r [os femoris) is not only the largest of all the cylindrical bones, but the greatest bone in the body. It is stronger than any other round bone, and so curved at its upper part, that it is convex forward and concave backward. Its upper extremity diSers much from that of the body ; for the almost spherical head which terminates it joins to this last at nearly a right angle, by a short but very manifest neck. Near the centre of the cartilaginous surface of this head, but rather downward than upward, is a considerable depression, which marks the insertion of the round ligament- The neck is slightly compressed fi-om before backward. At the place of its union with the body we remark two large processes, called trochanters {trochanter es). The large, upper, or outer trochanter arises from the upper and outer extre* mity of the body, curves very much backward and downward, and presents on its iirternal face a considerable depression, called the /ossa of the large trochanter. The inner, smaller, or inferior trochanter is situated lower than the preceding, and arises as a small truncated pyramid from the upper extremity of the internal face of the body, and inclines inward. Ridges extend fi-om the large to the small trochanter on the anterior and posterior faces of the bone, and give attachments to certain muscles. These are called the anterior and posterior intertrochanterian lines (linea intertrochanterica anterior et posterior) ; the latter is by far the most distinct.

(1) Walter mentions one case in his work. Von der Spaltung der Schambeine, Berlin, 1ÃŽ82.

(2) E. Sandifort, De ancylosi ossium pubis, in the Obs. anat. pathoL, book i. chap, vi. p. 115-125, tab. viii.

The anterior and external faces are so insensibly continuous with each other on the body, that we cannot trace the hmit between them ; and the bone is here round. The anterior and the internal faces are very distinct, and the external and the internal are still more so, as a very projecting ridge, called the rough line of the thigh bone {linea aspera ossisfenioris), exists between them. This ridge arises by two roots from the large and small trochanters, is more or less evidently divided into two lij)s {labia) in almost the whole length of the femur, and terminates by two branches at the lower sixth of the bone. The base of the body is also divided into four faces ; arr anterior, a posterior, and two lateral faces which are the narrov/est.

The inferior extremity of the body extends into an inferior p'oeess. This, the broadest and straightest part of the bone, has, generally considered, the form of a heart. We notice its two condyles {condyli ossis femoris), an external and an internal, the inferior, anterior, and posterior faces of which are insensibly continuous with each other, and thus form a broad surface, which is convex from before back-ward and from within outward, and is covered with cartilage. These two eminences are separated in every part by a fissure, which is very deep, especially in its posterior portion, where it is not covered with cartilage. This posterior part is the posterior intercondyloid fossa { fovea intercondyloidea posterior). The anterior is much flatter, is covered with cartilage, forms a part of the articular surface, and is called the anterior intercondyloid fossa {fovea intercondyloidea anterior). The two lateral faces of the condyles, which are destitute of cartilage, present elevations which serve for the attachment of the articular ligaments.

foramina of nidrition {foramina nutritia), are found upon and at the side of the linea aspera, but at different heights. We usually observe two, one of which is larger than the other and is always situated higher. Sometimes also there is only one, which is then found near the centre of the femur.

§ 753. The femur appears first toward the end of the second month of pregnancy, at which time its length but slightly exceeds its breadth and thickness. From the third month, however, it not only becomes longer, but its two extremities are evidently broader than its central portion : it however remains straight till birth, and its curve is not apparent till toward the end of the first year, and afterwards gradually increases. In general it is larger in the male than in the female. Ossification does not commence in the lower extremity till the last month of pregnancy ; a single rounded osseous nucleus then occupies the central portion, from whence it gradually extends to the two condyles. Some time after birth ossification begins also in the upper extremity, namely, in the head ; but it is not till the third or fourth year that ossification begins first in the large and then in the small trochanter. The neck, which is simply the body prolonged, is indicated but very imperfectly in the full grown fetus, and only on the inside by the greater breadth of the upper part of the bone, as also by the projection of its upper extremity. These five osseous germs, that of the head, of the body, of the two trochanters, and of the condyles, remain separated a long time after puberty, and are not all fused, even when the subject is perfectly developed. The small trochanter first fuses with the body, next the head, then the large trochanter ; the inferior extremity is fused the last.(l) This marked difference then exists between the ossification of the humerus and femur, that in the latter the lower, and in the former the upper extremity is the last to unite with the body.

§ 754. The femur articulates by its upper extremity with the iliac bone, and by the lower with the head of the tibia. .

§ 755. The greatest anomaly presented by it ii a great increase of its curve forward : this is seen principally in a|yects affected' with rachitis. More rarely the groove in the headrfor the insertion of the round ligament is deficient (§ 752). When the lower oxtremities are very imperfectly developed, this bone is sometimes wholly or at least in great part deficient. j

ARTICLE THIRD. OF THE BONES OF THE LEG.

§ 756. The leg, like the fore-arm, is composed of two bones, which differ in their relations with each other and with the adjacent bones, from those of the bones of the second section of the pectorabmembers. The larger is the iihia^ the smaller the fibula.

I. OF THE TIBIA.

§ 757. The tibia {facile metjus) forms the foundation of the leg, being five times as massive as the fibula. This bone is next in size to the femur, and is longer even than the humerus. It is situated on the inside of the leg.

(1) Albinus mistakes in saying that the two trochanters fuse at the same time, and does not point out the order in which the different nuclei of hone arc developed.

The direction of its body is almost straight ; it is however slightly convex forward and a little concave backward. Its three.faces are perfectly distinguished from each other by projecting edges. The anterior edge, which separates the internal from th-e external face and is directly under the skin, is sharp, and has hence been called the crest of the tibia {crista tibiæ) ; the external is acute ; the smoothest and most rounded of the three is the internal. The external face is concave in its upper two thirds, and is called the peronccal cavity {cavitas peronæa) from the direction of its hollow. The internal and posterior face is slightly convex. Above its central part the body is a little compressed from within outward, but gradually enlarges in its lower fourth and becomes more rounded, because its edges disappear in this portion of it.

There is generally but one foramen of nutrition, situated at the inferior extremity of the first fourth of the posterior face, near the outer edge.

The upper extremity, the thickest and broadest part of the bone, terminates in the condyles of the tibia {condyli tibiæ), which correspond to those of the femur. Both present on their upper faces, which are faced with cartilage, a superficial glenoid cavity {cavitates glenoideœ, externa et interna). Their internal edge alone projects slightly, especially in the centre. Their internal articular face is a little longer from before backward, but narrower in the same proportion from within outward, than the external face. They unite inwardly and produce an unequal elevation {acclivitas intercondyloidea), the direction of which is from before backward, but which is not as extensive as they are. This elevation corresponds to the posterior interconclyloid fossa of the femur. Before and behind it we observe an anterior and a posterior depression {fovea acclivitatis anterior et posterior), which has no cartilage. At the posterior extremity of the lateral face of the external condyle of the tibia is a small, round, smooth articular surface {facies articularis lateralis, s. peronea), faced with cartilage, the direction of which is obliquely downward and backward, to which is fitted the corresponding facet of the upper extremity of the fibula. The anterior face of this upper extremity presents in its centre, at the place where it unites with the body, a considerable projection, call the spine or tuberosity of the tibia {tuberositas tibiæ), which is insensibly continuous with the crest.

The lower extremity forms in its lower convex portion a considerable triangular tuberosity, the angles of which are however rounded ; this is called the internal malleolus {malleolus internus) ; on its posterior face is a groove, more or less deep, and the direction of which is from above downward and from without inward ; it is the interned medleolar groove {sulcus malleoli interni) . The external face of this extremity, on the contrary, is concave and receives the fibula. The lower face, which forms a right angle with the external face of the internal malleolus, is faced with cartilage, slightly concave from before backward to lodge the head of the astragalus, and is sometimes divided into two lateral portions by a slight eminence.

§ 758. The tibia developes itself by three points of ossifieation. The body appears toward the end of the second month of pregnancy. The osseous germ of the upper extremity does not appear till towards the last month, and then is seen in its centre. The inferior is wholly cartilaginous in the full-grown fetus, but begins to ossify immediately after birth. The fusion of these pieces of bone with the body is not completed till the subject is perfectly developed. The lower extremity fuses with the body before the upper extremity.(l)

§ 759. The tibia articulates by the upper faces of its condyles with those of the femur ; by its lateral articular facet with the head of the fibula ; and by its lower extremity with the astragalus.

§ 760. The anomalies of this bone are its entire or partial deficiency, which accompanies the imperfect development of the lower extremities, their curving inward {v(dgi) or outward («an), or rarely forward in those affected with rachitis.

n. or THE FIBUEA,

§ 761. The fibula {perone, facile minus cruris) is the second, and the weaker of the bones of the leg, being situated on its outside. It is nearly as long as the tibia, but does not extend so high above, while it extends a little below the tibia. The body has an irregular form, and it is twisted on itself We however distinguish in it three faces, which are very sensibly separated by as many edges. The anterior is not simply concave, but divided, in most of its extent, by a longitudinal crest into two parallel furrows. The external is concave in its upper part, and slightly concave downward. The internal is flatter, but in its upper part are prominent asperities for the attachments of some muscles. The anterior edge is the most acute, especially near the the central part of the bone, and hence it maybe called the crest of Ike fibula {crista fibulæ). The body of the fibula is much thicker in its centre and towards its upper extremity than in the rest of its extent.

The foramen of nutrition, which is alwaj^s single, is situated a little above the centre of the bone on its internal edge.

The upper extremity, the. head of the fibula (capitidum), represents an irregular scjuare, the upper face of which is directed obliquely from above downward, and from behind forward, and has on its posterior part an articular surface, which is cartilaginous and a little coircave, which corresponds to the lateral articular facet of the tibia (§ 757). This surface presents asperities, more or less distinct, to which muscles are attached.

The lower extremity is triangular, and slightly compressed from right to left; it descends backward a little lower than forward, and forms the external malleolus {malleolus externus). The upper and interior portion of its internal face unites to the lower face of the inferior extremity of the- tibia, at a right angle, to form the articular surface designed to receive the astragalus, and is covered with cartilage. The â– posterior and inferior half is rough, and very concave ; it is called the fossa of the external malleolus {fovea malleoli externi). Above and behind this fossa, and also before and above the articular surface, are two tubercles, a posterior and an anterior {tuberciila malleolÅ“ externæ posterius et anterkis), to which ligameirts are attached. The posterior face of the external malleolus presents a groove {sulcus malleoli externi), which is perceptible with difficulty.

(1) Albinus has neg-lectecl to mention the order in which the nuclei of bone in the tibia are developed and fused.

§ 762. The body of the fibula appears a little later than that of the tibia. In the fetus of ten weeks old, it is only about half as long as this last ; and it is not till the end of the third month that both bones have the same length. On the contrary, even in the full-grown fetus and in the child, the tibia is thinner in proportion to the fibula than at a later period. The two single osseous nuclei of the extremities do not begin to appear till after birth, and fuse only when the subject is fully grown. The inferior unites to the body before the superior, and always sooner on its external than on its internal edge.

§ 763. The fibula articulates upward with the tibia (§ 759), and downward with the astragalus (§ 772).

§ 764. This bone is sometimes deficient when the lower extremities are not perfectly developed, although the tibia may exist ; a curious analogy with some animals, resembling the fusion of the two bones into one as it is seen in several. Its lower part is then generally deficient ; sometimes however, although the tibia and the foot exist, (the latter being very imperfect) the upper part of the fibula is deficient, and only a small portion of its lower part exists, which terminates upward in a point.

m. OF THE PATELLA.

§ 765. H\\e patella ox rotula is a shorter bone situated on the anterior face of the knee joint, between the femur and the tibia. It has an irregularly quadrilateral form. The angle produced by the union of its lower edges is the most acute, and that by the upper, the most obtuse. The anterior face is convex, and presents numerous foramina of nutrition ; the posterior is covered with cartilage in all its upper portion, and is divided by a large projection into two slightly concave surfaces. This part is covered with cartilage, and is fitted to the anterior part of the articular surface of the lower extremity of the femur. The lateral fossæ receive the anterior parts of the condyles, and the central eminence is fitted into the anterior fossa.

The patella is situated in the substance of the tendon of the extensor muscles of the leg, which covers all its anterior face, but extends only upon those parts of its posterior face which have no cartilage. This tendon attaches it to the tuberosity of the tilfia. It corresponds perfectly, both in its situation and in its connection with, this tendon, to the olecÄinon process of the ulna ; and hence the tibia has no process which may be compared with the olecranon. The patella increases the analogy between the bones of the leg and those of the fore-arm.

§ 766. Ossification. of the patella does not commence till after birth. Portai is mistaken in saying that its posterior face is almost perfect in the full-grown fetus, and that it is developed by two points of ossification.(l) A nucleus of bone forms in the centre of the cartilage and gradually and slowly enlarges. We very rarely find several points of ossification ; Rudolphi however mentions an instance. (2)

ARTICLE FOURTH. OF THE BONES OP THE POOT.

§ 767. The foot comprises three divisions, the tarsus, the metatarsus, and the toes {digiti jjedis).

I. OF THE TARSUS.

§ 768. The tarsus is formed like the carpus of short and rounded bones very similar to the carpal bones, but differing from them in several respects, viz. in number ; the bones of the tarsus are only seven ; they are much larger and stronger, their mode of articulation with the bones of the leg differ, and they are arranged, not like the bones of the hand, in two rows, most commonly, but in three. On the other hand, the manner in which they articulate with each other, or with the metatarsal bones, is almost the same as that of the carpal bones, and it is much more exact to describe them as forming two rows.

I. OF THE POSTERIOR RANGE OF THE TARSAL BONES.

§ 769. The posterior range of the tarsal bones comprises the two largest, the astragalus, and the os calcis.

A. OF THE ASTRAGALUS.

§ 770. The astragalus {talus, astragedxis, os tesseræ) has a quadrangular but very irregular form. V/e distinguish in it a bodij, a head, and a neck.

The body is quadrangular, and is the posterior and largest part of the bone. Its upper face is covered with cartilage, is convex from before backward, and slightly concave from within outward. The direction of the upper part of the external lateral face is obliquely from above downward and from within outward, and, like the smaller and upper part of the internal face, it is covered with cartilage. The inferior parts of these two faces which have no cartilage present numerous asperities for the attachment of ligaments. The small posterior face is also uneven, and extends outward into a small tubercle. The inferior is covered with cartilage, is directed a little obliquely from without inward and from before backward, and is very concave. The anterior is not free except in its inferior half, and to a small extent of the outside of the superior ; it is continuous for the most part with the neck, which is short and very narrow upward, downward, and outward. The head is a little higher than the neck and extends much lower, but does not like the neck proceed outward as far as the body. Its upper face is .rough. The anterior is convex from without inward and from above downward, is- much more broad than high, and is covered with cartilage. The latter is usually divided into two portions by a slight eminence, the direction of which is oblique from before backward, and from without inward. Sometimes, but rarely, a portion which has no cartilage divides into two entirely distinct surfaces ; these differences however do not depend on sex,*nor is the arrangement on both sides of the same subject exactly the same.

(1) Anat. Med., vol. i. p. 472.

(2) Anat. physiol. Abh., p. 133.

§ 771. The rudiments of the astragalus appear first in the seventh month of pregnancy. In the full-grown fetus, it is a round nucleus of bone, the body and the head bemg then almost equal in size.

§ 772. The astragalus articulates, by the upper and lateral faces of the body, with the tibia (§ 759) and the fibula (§ 763), forming a ginglymus joint, which, besides the flexion and extension of the foot, admits only of a slight motion inward and outward. It articulates by the lower face of its body and its neck with the os calcis (§ 775), and by the anterior face of its neck with the scaphoid bone (§ 779).

B. OF THE os CALCIS.

§ 773. The os calcis {calcanéum) is the largest of the tarsal and even of the short bones, and is more than double the size of the astragalus. It is situated below the astragalus and proceeds equally as far forward, but extends much farther backward. Its general form is irregularly quadrilateral. Its greatest diameter is from before backward, and the smallest from within outward.

We may distinguish in it a body and an internal process.

The body is compressed laterally. It bulges backward and forms a large tuberosity {tuber calcanea) to which the Achilles tendon is attached, and which terminates downward and forward in two eminences, the internal being larger than the external. The external face is rough ; it usually presents forward two small tubercles which however are not constant, and seldom exist in both bones of the same subject. These tubercles, one of which is situated directly behind the other, form a species of groove. The outer face is generally smooth, the inner is a little concave from above downward and from before backward. The upper face forms two arches, the posterior of which is smaller and flatter, and extends from the upper extremity of the tubercle to the posterior extremity of the anterior arch. 'I'his latter is larger, and is composed at its anterior face of a cartilaginous convex articular surface, having a direction perpendicularly from behind forward, and of another portion situated forward, rough, very concave, and destitute of cartilage. In this place, the bone is much lower than in its posterior portion. Its anterior triangular face is slightly concave and covered with cartilage.

From the upper and internal edge of the anterior portion of the os calcis proceeds an oblong process, not broad, but very strong, which goes inward, and is called the lateral process {'processus lateralis, sustentaculum tali), on which the head of the astragalus rests. This process is separated, backward and upward, from the body, by a deep groove {sulcus sustenlaculi tali inferior). The upper face descends obliquely from before backward ; it is covered with cartilage and is concave. Its anterior part is usually narrower than the posterior, and most generally there is at the commencement of the anterior third a greater or less contraction, which is sometimes converted into a deep furrow, destitute of cartilage, which seems to divide its single face into two parts. This face corresponds to the inferior face of the body of the astragalus. Its division into two is much more common than the same arrangement in the astragalus, and the lower face of the head of this bone is not usually divided, even in those subjects where the separation of the upper face of the lateral process of the os calcis is complete.

The assertion that this articular surface is entire only in the female is incorrect ;(1) on the contrary, its division into an anterior and a posterior part is much more frequent in the female than in the male, where it is rare and less perfect. Farther, in both sexes we not unfrequently find the two arrangements in the two sides of the same subject, so that there are no peculiarities of sex.

§ 774. The os calcis is developed the first of all the tarsal bones. It begins to appear in the sixth month of pregnancy as a single nucleus in the centre of the cartilage. In the full grown fetus, this nucleus is nearly twice as large as that of the astragalus and goes farther forward but very little farther back than the latter, while in the adult the posterior forms almost half of the length of the bone. This difference arises from the fact that three-fourths of the os calcis at least, particularly all its posterior part, is still cartilaginous, and its osseous nucleus is situated directly below that of the astragalus. Afterward, that is from the eighth to the tenth year, there is developed in the tuberosity a single, flat, and rounded osseous germ which is much thicker downward than upward, and which increases from below upward. The lower part of this nucleus fuses with the body much sooner than the upper part. Sometimes also a third point of ossification forms in the upper part of the tuberosity. The perfect union of this nucleus with the body takes place only when the subject is fully grown. The form of the os calcis, its slow development, and its connexions with the Achilles tendon, are circumstances worthy of remark, as establishing an analogy between it and the patella, and the olecranon process of the ulna.

(1) SÅ“minering-, Knochenlehre, p. 410

§ 775. The os calcis unites to the bones of the leg but does not articulate with them, although attached by strong fibrous ligaments. It articulates by the upper articular surface of its body, with the body of the astragalus ; by the upper articular surface of its process, Avith the head of the same bone (§ 772) ; and by the anterior face of its body, with the cuboid bone (§ 782).

II. OF THE ANTERIOR RANGE OF THE TARSAL BONES.

§ 776. The anterior range of the tarsal bones is formed of five bones, which are smaller than those of the posterior range, and of which four articulate with the latter by their posterior extremities, while the fifth is situated between the three internal bones of this range and the posterior range. Two of these bones, the scaphoid bone and the cuboid bone are usually considered as the second range of tarsal bones, because their posterior faces articulate with the astragalus and the calcanéum ; but as the cubgid bone also extends as far forward as the other three which are usually'considered as the third range, and as it articulates like the latter with the metatarsal bones, it is more proper to regard these five last as forming only one range.

A. OF THE SCAPHOID BONE.

§ 777. The scaphoid bone (os navicidare) is situated before the astragalus, behind the three cuneiform bones, and on the inside of the cuboid bone. It makes part of the posterior and internal portion of the anterior range of the tarsal bones. Its breadth exceeds its height very much, and its thickness still more. Its posterior cartilaginous face is concave and smooth ; its anterior is larger and also covered with cartilage, convex, and divided by three eminences which extend from above downward, into four compartments, which diminish in extent from within outward. The upper and convex face is very rough. So too with the inferior which is straighter. At the place where these two faces meet, on the internal edge of the foot, the bone forms a projecting angle, called the tuberosity of the scaphoid bone [tuberositas ossis navicidaris) .

§ 778. Ossification of the scaphoid bone does not commence till after birth, and usually towmrds the end of the first year.

§ 779. This bone articulates by its posterior face with the anterior face of the head of the astragalus (§ 772), and by the four compartments of its anterior face with the three cuneiform bones (§ 784, 793), and also with the cuboid bone (§ 782).

B. OF THE CUBOID BONE.

§ 780. The cuboid bone {os cvhoideumi) derives its name from its form which is irregularly quadrilateral. It is longer from before backward than from one side to the other, and from above downward. Its posterior triangular face is covered with cartilage, and is slightly concave ; the internal is rough in most of its extent ; it is covered with cartilage at its central and upper portion ; this cartilaginous surface is divided into two halves by a process which goes from above downward, of which the external half is the larger, lire anterior face, situated on a short, slightly contracted eminence, is square, covered with cartilage, and also divided by a projection which goes from above downward into two halves, of which the external is the larger. The upper face is almost plane and slightly uneven. The external is the smallest, and in the place where it is continuous with the inferior, it forms a tuberosity which also extends across the whole breadth of the inferior face and which produces the oblique eminence of the cuboid bone {eminent ia obliqua ossia cuboidei). Between this tuberosity and the anterior edge of the face, a deep furrow {sulcus ossis cuboidei) extends in an oblique direction. The portion of the external face situated behind tire tuberosity is also concavp and rough, but less so than the other.

§ 781. Ossification of the cuboid bone commences before birth, but not till towards the end of the eighth month of pregnancy, although it is far advanced in the full grown fetus.(l)

§ 782; This bone articulates by its posterior cartilaginous face, with the anterior face of the body of the calcanéum (§ 776) ; by the posterior half of the portion of its internal face which is covered with cartilage, with the must external and smallest compartment of the anterior face of tho scaphoid bone (§ 779) ; by the anterior part of this same portion, with a part of tho external face of the third cuneiform bone (§ 792) ; finally by its anterior face with the posterior extremities of the two external metatarsal bones.

O. OF THE CUNEIFORM BONES.

§ 783. The three cuneiform bones {ossa cuneiformia), which have received this name from their common resemblance to a wedge, are situated between the scaphoid, the cuboid, and the three inner metatarsal bones. They are all triangular, contracted from within outward, and much broader at one extremity than at the other, where they terminate by a more or less sharp edge. They are not equal in size.

(1) Albinus says Maturo (fœtu) etiam nonnisi calccus et talus -pcrtcm osscam habent, and every anatomist tiaa fallowed him. Itut this is a mistake as may easily be seen by examining' the skeleton of a full grown fetus.

a. Of the first cuneiform bone.

§ 784. The first cuneifionn called also the large or internal cuneifioinn bone assists to form the internal edge of the sole of the foot. It is situated between the inner part of the scaphoid bone and the metatarsal bone of the large toe. It is very much larger than the other two andj from its position, the sharp edge is directed upward. Its free inner larger convex face is very rough. The external is a little concave, is still more rough. We remark along its upper and most of its posterior edge a straight band, \vhich is covered with cartilage and divided forward by a small eminence in two parts ; the anterior is smaller, and is directed a little obliquely from behind forward and from within outward. The inferior face is slightly convex and very rough. The anterior, almost plane, is in the form of an ear, that is, it is surrounded inward by a convex edge, and outward by a concave edge slightly grooved at its central part. The posterior is triangular, concave, and entirely covered with cartilage.

§ -785. In the full grown fetus there is no nucleus of bone for the large cuneiform bone.

§ 786. It is articulated by its posterior face, with the most internal compartment of the anterior face of the scaphoid bone ( §779) ; by the greater posterior part of the cartilaginous portion of the external face, with the second cuneiform bone (§ 789) ; by the small anterior part of this same portion, with the second metatarsal bone (§ 799) ; finally, by its anterior face, with the posterior face of the first metatarsal bone (§ 797).

b. Of «he second cuneiform bone.

§ 787. The second cuncifiorm hone called also the smallest cuneiform bone is about one third the size of the preceding. It is particularly much narrower from above downward and from before backward, so that its extent downward or forward is not so great, although upward and backward it proceeds as far as that. It is situated so that its broad face forms a part of the back of the foot, while its lower, sharper, and wedge-shaped edge looks toward the sole. The upper face is square, convex, and slightly rough ; the posterior and anterior are triangular, strait, and covered with cartilage. Most of the internal edge is also covered with cartilage ; it is destitute of it in but two small slightly concave spaces, the posterior of which extends nearly in a straight line from the centre of the lower edge to the upper, without however reaching it, while the anterior occupies the lower part of the anterior edge. The external face is covered with cartilage in its upper and posterior part, and is uneven and roirgh in its anterior.

§ 788., Ossification does not begin in this bone till after birth, and a little later even than in the large cuneiform bone.

§ 789. The second cuneiform bone articulates by its posterior face, with the second compartment of the anterior face of the scaphoid bone (§ 779) ; by the interior, with the first cuneiform bone (§ 786) ; by the external, with the third cuneiform bone (§ 792) ; and by the anterior, with the second metatarsal bone (§ 799).

c. Of tile tlilrJ cuneiform bone.

§ 790. The third cuneiform hone is about half the size of the first. The form and direction of its faces resemble those of the second very much, but it is a little more contracted from within outward than the last. It is as long from before backward as the first, so that it proceeds equally as far forward ; but as it is lower and does not equal it in height, it does not extend equally 'as far downwctrd.

The larger and upper portion of its triangular and plane posterior face is faced with cartilage ; so, too, of the upper and posterior half of the external face, while its inferior and anterior part, which is more extensive than the other, is uneven and rough. Almost all the internal face is very rough and destitute of cartilage. We only perceive a layer of cartilage some lines broad, along the upper part of its posterior edge, and two others which are smaller and rounded, situated one above tha other, and occupying nearly the same extent along the anterior edge. The anterior face is slightly concave and triangular, and is every where covered with cartilage.

§791. The third cuneiform bone, although much smaller than the first and the scaphoid bone, ossifies before them, and it appears not in the full-grown fetus, but at the end of the first month, as an osseous germ which is very considerable.

§ 792. It articulates by its posterior face, with the third compartment of the anterior face of the scaphoid bone (§ 779) ; by its anterior face, with the third metatarsal bone (§801); by the posterior and cartilaginous part of the internal, with the second cuneiform bone (§ 789) ; by the two anterior cartilages of the same face, with the second metatarsal bone (§ 801) ; finally, by the cartilaginous portion of its external face, with the cuboid bone (§ 782.)

II. OF THE METATARSAL BONES.

§ 793. The metatarsus is composed, like the metacarpus, of five cylindrical bones, which are formed generally after the same type, and are nearly equal in length ; but which, independently of several less important differences, vary much in thickness. Like all cylindrical bones, the body is thinner than the extremities, and presents three faces which are separated by as many edges : the inferior is usually the sharpest. Among these faces, one looks more or less upward, and is called the superior or dorsal {faces dorsalis) : the other two are lateral, an external and an internal. The bone considered as a whole, is sightly arched ; hence it appears slightly convex above and more strongly concave below.

The posterior extremities or the hases {basis), are generally triangular. They terminate backward by more or less plane and cartilaginous surfaces, by which they articulate with the anterior range of the tarsal bones. They are also furnished on one or on both sides with one or more facets, by which they are fitted to each other and to the bones of the anterior range of the tarsus. Besides, part of the lateral faces of these posterior extremities is rough for the insertion of fibrous ligaments.

The anterior extremities or the heads (capiiula), are generally thinner than the posterior, rounded and terminated forward by an articular convex surface, behind which is a depression {sinus) which surrounds all the head. Beyond this depression we observe four tubercles, one at the upper and tho lower part of each side.

As the anterior and posterior extremities of the metatarsal bones extend beyond the body in every direction, we. observe between every two of the metatarsal bones an interval called an interosseous space {interstitium interosseum) .

§ 794. The metatarsal bones gradually form by the union of two pieces of bone. The largest, which represents the body, appears first in the third month of pregnancy, and is perfectly developed in the fullgrown fetus. The processes do not begin to ossify until the second year. These two pieces of bone do not fuse entirely till about the period when the subject is perfectly developed ; but they do not all unite at the same time in all the metatarsal bones. It is remarkable, that here, as in the metacarpus, the first bone differs from the four others, by the development of its second germ in the base, instead of forming in the head as it does in the latter, which renders this and the metacarpal bone of the thumb similar to the first phalanx of the hand and foot.

§ 795. The 'metatarsal bones articulate by their posterior faces, with the anterior range of the tarsal bones ; most of them by their posterior faces, with each other ; and by their airterior extremities, with the first phalanges of the toes.

I. OF THE FIRST METATARSAL BONE.

§ 796. The^^rsf metcdarsal bone^ or the metatarsal bone of the great toe, is much largei» but shorter than the other. Of the three faces of its body, the upper is inclined a little inv/ard, the internal is concave and inclined downward ; and the external is almost plane, and its direction is perpendicularly from above downward. The internal and external edges unite with each other at an obtuse angle, and with the superior edge at a right angle. The base is very elevated, in proportion to its breadth, and backward presents an earshaped surface, the convex edge of which looks inward, and the concave edge outward. We often, but not always find, at the upper part of the external lateral face of its posterior extreihity an oblong, plane or slightly concave cartilaginous articular facet, which corresponds to an analagous facet of the second metatarsal bone.

The head is broader than those of the other metatarsal bones, and the articular facet is divided by a strong longitudinal crest into two depressions, which extend from the centre to the posterior edge, and of which the external is deeper than the internal.

§ 797. The first metatarsal bone articulates by its posterior extremity, with the anterior face of the large cuneiform bone (§ 786) ; sometimes by the external lateral face of its base with the second metatarsal bone (§799) ; by the upper part of its anterior extremity, with the posterior extremity of the first phalanx of the great toe ; by the inferior, with the two sesamoid bones, which are found in the flexor muscle of the great toe.

II. OF THE SECOND METATARSAL BONE.

§ 798. The second metatarsal hone is the largest of all, and extends further backward than the others, except the fifth. Its base has the form of an equilateral triangle, the summit looking upward': it is very concave, especially at its upper part, and its external edge is very much notched. The internal lateral face presents a plain cartilaginous facet, which varies in situation, sometimes existing directly before the internal edge and at the highest part of the posterior face, and sometimes much more forward and downward, and separated from this edge by a groove for the attachment of a ligament. The external facet presents two articular facets, situated one above the other, and separated by a depression which varies in size, extent, and form ; the upper differs considerably, being sometimes very long from before backward, and divided into two parts by a longitudinal eminence; sometimes it is shorter and single, or at least is divided imperfectly.

The upper face of the body is turned entirely inward, whence the internal edge is in fact the upper. The depression situated between the anterior articular facet and the tuberosities, is broader than in the following bones of the metatarsus.

§ 799. The second metatarsal bone articulates, by its posterior face, with the second cuneiform bone ; by the internal lateral face of its posterior extremity, in the formation first described (§ 798) with the large cuneiform bone; and in the second mode (§ 798), with the first metatarsal bone (§ 797) : by the anterior segment of the upper portion of the external face of its base, with the third metatarsal bone (§801): by its posterior segment, with the third cuneiform bone (§ 792), a connection which is sometimes perceptible with difficulty, and is often deficient ; finally, by its lower face, with the third metatarsal bone (§ 801) and the third cuneiform bone (§ 792), and sometimes with only one of them.

in. OF THE THIRD METATARSAL BONE.

§ 800. The third metatarsal hone is freijuently the shortest. of all. It is compressed laterally in all its length. Its posterior extremity advances a little farther than that of the second. Its posterior articular face is also triangular, but a little narrower and even. Directly before the posterior edge of the internal lateral face we observe, sometimes, one facet, and sometimes two, situated one above the other, aird separated by a depression which presents no cartilage. This facet has a a rounded triangular form. The external lateral face presents one which is always single, but more extensive, situated exactly opposite the internal. The body and the head are formed as in the preceding bone.

§ 801. This bone articulates by the posterior part of its base, with the third cuneiform bone (§ 793) ; by the internal face, w-ith the second metatarsal bone (§ 799) ; by the external, with the fourth (§ 803); and by the anterior face of its head, with the first phalangeal bone of the third toe.

IV. OF THE FOURTH METATARSAL BONE.

§ 802. The fourth metatarsal hone is usually a little longer and always extends back farther than the third. It is less compressed from one side to the other than the second and the third ; hence its body is more rounded and its upper face is turned directly upward, while the other two are turned to the sides. The posterior face of the base is lower than in the second and third metatarsal bones, is oblong, and a little more concave. On the internal lateral face is a surface which is sometimes single and sometimes divided into two unequal parts by a perpendicular eminence, and which is separated from the posterior face by the attachment of a ligament. This surface is oblong and very extensive, slightly convex, and covered with cartilage ; it occupies the upper half of this face. The external lateral face presents a similar triangular, flat, articular surface, which extends to the posterior face, both before and below which is the attachment of the ligament.

§ 803. This bone articulates by its posterior face, with the internal segment of the anterior face of the cuboid bone (§ 782); by the internal, sometimes with the third metatarsal bone alone (§ 801), sometimes as in the second (§ 802), by the posterior segment of the cartilaginous face with the third cuneiform bone, which then presents a small cartilaginous facet at the anterior and upper part of its external face ; finally by the external lateral part of its base, with the fifth metatarsal bone.

V. OF THE FIFTH METATARSAL BONE.

§ 804. The fifth metatarsal bone has the same length as the fourth. It differs in form from all the others. The body is not compressed from one side to the other or rounded, but flattened from above downward, especially in its external portion, formed by the upper and external faces, the last of which has become entirely inferior, and which are separated from each other by a sharp edge. Thebody also is thicker than the bodies of the second, third and fourth metatarsal bones. The base is triangular and compressed, not from right to left but from above downward, which makes it more broad than high. Its posterior face is very oblique from behind forward and from without inward. Its base is not, as in the other metatarsal bones, entirely covered with cartilage ; this is seen only on its internal portion, which is flat, triangular, and almost rounded, while the external is smaller and separated from the preceding by a perpendicular fissure, and has a considerable eminence {tuberositas), which is rounded and turned outward, and which renders the bone very broad in this part. The internal face of the base has on its upper part a broad, flat facet which is covered with cartilage. The head is more broad than high ; it is also often narrower and lower than the body. From the great convexity of the internal face of the fifth metatarsal bone and the slight concavity of the external face of the fourth, the fourth interosseous space is very narrow.

§ 805. This bone articulates by its posterior face, with the external segment of the anterior face of the cuboid bone ; by the internal face of its base, with the fourth metatarsal bone ; and by its head, with the first phalangeal bone of the fifth toe.

III. OF THE BONES OP THE TOES.

§ 806. Wc count fourteen bones in the toes, each one having three phalanges excepting the large toe {hallux), which has only two. These bones of the phalanges belong to the class of long bones, and resemble perfectly in their most essential characters those of the fingers (§ 725, 726.)

I. OF THE FIRST PHALANX.

§ 807. The first or the posterior phalanx is the longest. The two extremities of these bones are much thicker than the body, especially the posterior, which is much higher and broader than the anterior. The body on its inferior face is concave from before backward and straight from one side to the other. The upper is straight in the first direction and very convex in the second. These two faces are separated from one another by an external and an internal lateral edge.

The posterior extremity, the base {basis), presents posteriorly a very concave articular surface, which is rounded and broader in the phalanges of the first and fifth toes than in the others. We observe on each side, where the upper face is continuous with the lower, a very projecting tubercle {tuberculum)

The anterior extremity, or the head {capitulum), is broad, and forms before an articular surface, which is slightly concave from above downward and presents on each side a rounded depression {sinus), behind which we see a tubercle.

Among the phalanges of the first range that of the large toe is the largest. It differs also from the others in being flat and contracted from above downward.

§ 808. These bones are developed much later than those of the metatarsus, and generally do not begin to appear till toward the end of the fourth month of pregnancy, except in the lirst phalanx of the large toe, which appears sooner than the others.

§ 809. They articulate posteriorly with the anterior extremities of the metatarsal bones, and anteriorly with the posterior extremities of the bones in the second phalanx.

II. OF THE SECOND PHALANX.

§ 810. The bones of the second phalanx {phalangini) are generally constructed after the same type as those of the first; but they differ from them : 1st. In their length, which is less, although they are nearly as broad ; hence they are nearly as broad as they are long. 2d. They are much flatter from above downward. 3d. There is less of difference in respect to the thickness of their bodies and extremities, which sometimes do not differ. 4th. The forms of their articular surfaces vary ; in fact the posterior is broader and divided by a longitudinal projection into two slightly concave lateral portions, while the anterior, which is slightly concave, does not present the longitudinal groove at its central part.

§ 811. Ossification does not commence till after the fifth month of pregnancy.

§ 812. These bones articulate by their posterior extremities with the heads of those in the first phalanx, and by their anterior with the posterior extremities of the third range of bones.

III. OF THE THIRD PHALANX.

§ 813. The bo7ies of the third phalanx { phalanx tc7-tia, s. nngninis) are composed of a very small body, of an anterior and a'posterior extremity, which are larger. The posterior extremity on its posterior face is covered with cartilage, rounded, oblong, much more broad than high, and simply concave, except in the first, where this surface is divided by a slight eminence into two lateral parts. The edge of the posterior face is surrounded by a depression, before which are numerous asperities which extend all round the bone. The anterior extremity or the summit is rounded and very rough.

§ 814. This phalanx ossifies before the second. The anterior phalanx of the first toe appears sooner than the posterior and even than all the other phalanges. The point of ossification is not developed first in its centre but at its summit.

§ 815. These bones articulate by their posterior extremities with the anterior extremities of those in the second range. They are often fused with the latter ; this must doubtless be ascribed to pressure, since the fusion is usually observed in the external toes, on which compi'ession acts with most force.

SECTION IV. COMPARISON OF THE BONES IN THE DIFFERENT REGIONS OF THE BODY

§ 816. Like all the organs, the bones of the right and left sides are the most similar ; the analogy is even so great between them in this direction that it is almost equivalent to a perfect resemblance, since the differences are too slight to be noticed.

We consider next the longitudinal direction ; here we observe, 1st, that the bones of the upper and lower halves of the trunk correspond.

The central region of the trunk, that which is formed by the dorsal vertebra?, the ribs, and the bones of the sternum, divides into an upper and a lower half ; for the ribs diminish very much in length both above and below the prÅ“cordial region, and the upper and lower pieces of the sternum may be compared to each other, since both terminate by jagged edges.

The lumbar and the cervical vertebrae are analogous in their want of ribs. The greater number of the cervical vertebrae is compensated for by the greater volume of the lumbar.

The head corresponds to the sacrum and the coccygæal bones.

But the analogy betwen the bones of the upper and lower extremities is striking. This analogy is seen ;

1st. In the number of the divisions of the limbs. In fact each extremity is divided into four regions or sections.

2d. In the form and the number of the bones which serve as the bases of each of these regions.

The iliac bone of the lower extremity corresponds to the scapula and the clavicle of the upper. The two extremities differ, as the upper possesses two bones, while one only is found in the lower ; but this difference is unimportant, and besides it does not exist in the early periods of life. The iliac bone is formed by the union of three principal pieces ; the posterior, the largest and broadest, called the ilium, corresponds to the scapula ; the anterior, narrower, called the pubis, represents by its body the coracoid process, and by its horizontal branch the external part, of the clavicle ; the inferior, which is thicker, called the ischium, corresponds by its body and descending branch, to the acromion process of the scapula, and by its ascending branch to the anterior part of the clavicle. The crest of the ilium and the base of the scapula, the coracoid process and the pubis, the acromion process and the ischium, are developed by special nuclei of ossification.

We find only one bone in the arm and one in the thigh ; they correspond perfectly in form and mode of development. Both have a rounded head, and the tubercles of the humerus represent the trochanters of the femur. At the lower extremity we see a surface in the form of a pulley, constituting a ginglyrnus joint.

The fore-arm and leg have each two bones which are verj' analogous. The upper extremity of the ulna terminates in a pulley like that of the tibia. These two limbs present a bone which articulates by ginglymus with that of the second division. True, the upper extremity of the uhia rises much higher than that of the tibia, but this is owing to a peculiar piece of bone which corresponds to the patella. This last ought to be considered as a process of the tibia, which never unites with the body of that bone ; and the olecranon process of the ulna also sometimes remains, like it, distinct and separate from the ulna through life.(l)

The lower extremity of the ulna differs from that of the tibia by its smallness, but that of the radius is very similar to the inferior extremity of the fibula, which should be considered as a true compensation, since in the motion of pronation the upper extremity of the radius comes below the upper extremity of the ulna. In fact if we unite the lower portions of the ulna and radius, we obtain a bone very similar to what the tibia would be if the patella were joined with it. This analogy is rendered still more evident by another circumstance, — that the bones which succeed the tibia correspond to the anterior extremity of the radius ; and it is favored also by comparative anatomy. In most quadrupeds, pronation is the proper state of the anterior extremity, so that the lower extremity of the radius is always situated on the inside. In others, the ulna does not extend to the carpus ; and as for this reason its lower extremity does not articulate directly with any bone of the carpus in man, so the tibia unites to the fibula in most quadrupeds, and only the former bone descends to the tarsus. The upper and lower extremities of the tibia present on their fibular face a cartilaginous facet, like those on the radial face of the ulna, by which the two bones articulate with each other .

In this manner the analogy between the fore-arm and the leg becomes much more evident. The ulna and the tibia however on one side, aird the radius and the fibula on the other, resemble each other in this point of view also, that the upper extremity of the first two possesses the greatest volume, while in the latter two the inferior is the largest.

Both bones run on their lower extremities and on the sides which are opposite to them rounded extremities, constituting the styloid processes and the malleoli. The radius is shorter than the ulna, and the fibula is shorter than the tibia, more especially if the patella be united with it.

The analogy between the bones of the hand and foot is very evident.

Those bones which correspond the least are the bones of the carpus and tarsus, which differ very much in size, those of the former being about a fifth as large as those of the latter, and being arranged also in a different order. We may however discover great analogies between them. The posterior carpal range coiTesponds to the os calcis, the astragalus, and the scaphoid bone. The anterior part of the scaphoid

(1) Delachenel, Obs. anat. mcd., Bâle 1706, § 28. — Roseiiiniiller, Ue oss. variet., Leipsic, 1804, p. 62.

bone of the hand resnnhles pevfcclly that of the foot. 'I'hese bones arc situated at the side of, and not over each other ; and we lind more in the hand than in the foot, as the former requires more motion and the latter more solidity. Hence why several bones of the posterior range articulate with the carpal extremity of the bones in the fore arm and with the boires of the anterior range.

The number of the bones in the anterior range which articulate directly with the metacarpus and the metatarsus is the same. It is especially remarkable that both extremities of the last two bones of the middle section (the metacarpus and the metatarsus) are supported by but one bone, while each of the other three articulates with two bones.

The arrangement of the articular faces which unite the bones of the anterior range with each other, or with those of the metacarpus and metatarsus, are very similar. Thus the trapezium and the first cuneiform bone present forward a small facet, by which they articulate with the second metacarpal and second metatarsal bone. The second metacarpal bone on its idnar side and the second metatarsal bone on its fibular side present an articular surface, divided into two portions, of which the anterior articulates with the succeeding metacarpal or metatarsal bone, and the posterior with the third cuneiform bone in the foot and the os magnum in the wrist. The third, fourth, and fifth metacarpal and metatarsal bones do not articulate, except with the corresponding bones of the carpus by their posteiior face, and rarely articulate with each other.

The metatarsal and metacarpal bones resemble each other also in number, form, mode of development, and connections. In both, the first of these bones present analogous proportions, although not entirely similar in regard to the others, for they are thicker than these. The second is longer both in the hand and foot. The tubercle which increases the size of the fifth metatarsal boire exists at least in a rudimentary state in the fifth metacarpal bone. The first metacarpal and the first metatarsal bones difl'er from the others in their mode of development and in the same manner.

The phalanges of the fingers and toes are also formed on the same fundamental type, and however great may be the difference between them, they are modifications of the same formation.

The differences between tlie bones of the upper and lower extremities depend on the differences of their functions. They may be referred, 1st, to the greater solidity necessary for the pelvic limbs to sustain the trunk and the head, and the greater degree of mobility necessary to increase the relations of the organism with external objects ; 2d, to the greater mass of the inferior extremities.

Hence why the iliac bones are united with each other and with the sacrum by a fibro-cartilaginous mass which admits of no motion, and why the anterior and posterior pieces of the iliac bone on each side fuse into one, while the scapula remains distinct from the clavicle. Hence also the reason that the scapula is attached to the vertebral column only by mu, scies, and that the clavicle is united in front with that of the opposite side, the sternum and the first rilr, only by loose synovial and fibrous Ugaments. Hence, finally, the reason that the mternal edge of the bones of the pelvis is very broad and that of the scapula very thin.

The cotyloid cavity of the femur is very deep, the coiTesponding glenoid cavity of the scapula is on the contrary flat, so that the scapulo-humeral articulation is secured only by the adjacent processes and by the external ligaments.

Hence the head of the femur is much larger than that of the humerus. We cannot perceive at all on this last a depression to receive the round ligament which strengthens the ilio-fernoral joint witlrin the capsule.

The body of the humerus is tvvfisted, that of the femm‘ is almost straight and arched in only one direction.

The humerus is destitute of a neck, and its tuberosities are not distinctly marked. The trochanters in the femur are largely developed, and the neck, which is very long, separates from the body to extend the head into the cotyloid cavity.

The differences observed in the lower ends of the two bones, and in the arrangement of the knee and elbow joints, produce exactly the same effect.

In the upper extremities the articular surfaces are surmounted on each side by large condyles which do not exist in the lower extremities. In the latter the joint is a ginglymus, and deep depressions exist between the two condyles of the femur and asperities between those of the tibia. There we find, beside the ginglymus articulation which is more plane, a rounded head, for the rotatory articulation with the radius.

In the lower extremity one bone only, the tibia, is connected with the femur ; the fibula articulates only with the tibia, of which it in some measure forms a part. In the upper extremity both bones of the fore-arm articulate with the humerus, and the radius moves very freely. The bones of the fore-arm, which are united above and below by loose attachments, and which are nearly of the same size, can be displaced in several different ways in relation to another, and these changes allow the hand to perform very important motions. The firm union of the bones of the leg, both at their upper and lower parts, and also the fact that the fibula from its small proportional development should be considered as a part of the tibia, causes the two bones to be almost motionless upon each other, and the motions of the foot to be simply flexion and extension.

The articulation of the foot is much more firm than that of the hand, both because the malleoli descend very low, and fi'om the form of the articular surfaces of the bones of the leg and astragalus, whence these bones articulate with only one bone of the tarsus.

The bones of the tarsus are attached to one another by very solid bands ; the pisiform bone, which is loosely articulated, is entirely deficient, or rather this bone is represented by the sesamoid bone in the tendon of the peroneus longus muscle.

Their mass exceeds that of the bones of the carpus ten times.

The bones which are situated at the side of each other in the carpus, are arranged before each other in the tarsus.

The metatarsal bones are larger, narrower, antî more contracted, while those of the metacarpus are broader, concave, and better disposed to grasp and hold objects.

The metatarsal bone of the great toe is much stronger and thicker than the metacarpal bone of the thumb, and cannot separate itself from the others as this can.

The same differences exist between the phalanges of the fingers and toes as between the metatacarpal and the metatarsal bones ; only those of the toes, excepting the first, are much shorter and more imperfectly developed.

The phalanges of the toes are the only exceptions to the second of the general differences pointed out between the twm hmbs, since they are smaller than those of the corresponding fingers.

§ 817. The resemblances between the anterior portions of the body and the posterior are in this as in the other systems the slightest of all. We however have already shown that the sternum coiTesponds to the vertebral column, the frontal bone to the squamous portion of the occipital bone, the. arches to the bodies of the vertebrae.

END OF VOL, I.