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other. The marrow occupies the tube left cavities, nor pores; but resembles the secin the middle of the long bones, and also tion of a piece of glue. It possesses a very fills the cancelli of their extremities. high degree of elasticity; which property

The cellular substance, which contains distinguishes it from all other parts of the the marrow, being condensed upon the in- body. Hence it enters into the composition side of the walls of the bone, and adhering of parts, whose fanctions require the comto them, lias been termed the periosteum in- bination of firmness with pliancy and flexiternum.'

bility: the preservation of a certain exterWe observe in the principal bones arte- nal form, with the power of yielding to exries, much larger than those which nourisht ternal force or pressure. the bone, penetrating these bodies obliquely, Cartilages are covered by a membrane, and spreading their branches npon the me- resembling, in texture and appearance, as dullary cells.

well as in its office, the periosteum of bones : Various unsatisfactory opinions have been this is termed the perichondrium. They reproposed concerning the use of the marrow. ceive arteries and veins from this memThe utility of the bones being formed as brane: these vessels, however, have never they are, small and tubular in the middle, been demonstrated in the cartilaginous expanded and spongy at their extremities, crusts of articular surfaces. Absorbent veshas been already explained. If then spaces sels cannot be actually shewn, but their exare necessarily left in their interior parts, ' istence is abundantly proved by many phethose spaces milist be filled with something ; nomena. The conversion of cartilage into for they cannot be left void, or the immense bone is alone sufficient for this purpose. pressure of the atmosphere would crush The cartilaginous substance is gradually retheir sides, and destroy the vacuum. There moved, as the formation of the bone adis no matter in the animal body more suit.

In affections of the joints, their able to fill their spaces than the marrow; cartilaginous coverings are often both enand it is to be regarded as a part of the adi- tirely destroyed, or partially removed ; pons system of the aninial.

which appearances can only be ascribed to From the circumstances which have been the action of absorbent vessels. detailed in the foregoing account, viz. the It does not seem to possess nerves, as it · great and general vascularity of bones ; the is entirely destitute of sensibility. quantity of soft substance existing in every The thinner cartilages of the body are re. part of them; their growth and mutation of solved by maceration into a kind of fibrous form in disease, &c. it is natural to con substance: e. g. those of the organs of sense. clude, that there exist in the composition of Those of the ribs are found by long maceevery bony fibre, arteries for its formation, ration to consist of concentric oval laminæ. absorbents for its removal, cellular sub. In some there are tendinous fibres interstance for the connexion of its parts, and mixed; as in those of the vertebræ. nerves to give animation to the whole. In

Anatomists divide cartilages into two this view of the subject, we see no essential kinds: the temporary and the permanent. difference of structure between bones and The former are confined to the earlier stages other parts of the body; nor do we expect of existence; the latter commonly retain any essential difference in the functions of their cartilaginous structure throughout their nutrient and other vessels. We natu

every period of life. rally conclude that bony fibres are formed The temporary cartilages are those in and repaired, and that they undergo muta which the bones of the body are formed. tion and removal in the same manner, and They are hence called by the Latin writers from the same causes that soft parts do. ossescentes. All the bones of the body, ex

cept the teeth, are formed in a nidus of

cartilage. The form of the bone, with its is a semipellucid substance, of a milk-white various processes, is accurately represented or pearly colour, entering into the compo- in these cartilaginous primordia ; and it is sition of several parts of the body. It holds the substance alone which changes. a middle rank, in point of tirinness, between The permanent cartilages are of various bones or hard parts, and the softer consti- kinds. We find them con posing the extertuents of the human frame. It appears, on nal ear, external aperture of the nostrils, a superficial exantination, to be homoge- and eve lids.' The larynx is entirely comneous in its texture : for, when ent, the sur posed of this substance; and the trachea, face is uniform, and contains no visible cells, with its branches, is furnished with cartila.

CARTILAGE

ginous hoops, by which these tubes are kept 1. Synchondrosis, where cartilage is the permanently open, for the ready passage of connecting medium: this is exemplified in air to and from the lungs.

the junction of the ribs and sternum ; of the The bodies of the vertebræ are joined by bodies of the vertebræ; and of the ossa large masses of a peculiar substance, par- pubis: taking of the properties and appearance of 2. Synneurosis or syndesmosis; where cartilage and ligament; which allow of the ligaments are the connecting bodies, as in motions of these parts on each other, with all the moveable articulations : out weakening the support that is afforded 3. Syssarcosis; where muscles are stretchto the upper parts of the body in general, ed from one bone to another. and to the head in particular, by the verte The synarthrosis, or immoveable conjuncbral column. These cartilages impart a

tion of bones, consists of, great elasticity to the spine ; by which the 1. Suture ; where the bones are mutually effects of concussion from jumping, from indented, as if sewn together: falls, &c. are weakened, and destroyed, be 2. Harmonia ; where the conjunction is fore they can be propagated to the head. effected by plane surfaces. When the body has been long in an erect 3. Gomphosis ; where one boue is fixed position, the compression of these cartilages, in another, as a nail is in a board. The by the superior parts, diminishes the height teeth afford the only specimen. of the person. They recover their former Diarthrosis, or moveable conjunction of length, when freed from this pressure: hence bones. The conjoined parts of the bones a person is taller when he rises in the morn are covered with a smooth cartilage, and ing, than after sustaining the fatigues of the connected by one or more ligaments. It day, and the difference has sometimes has three subdivisions; viz. amounted to an inch,

1. Enarthrosis, or ball and socket ; where Cartilages are sometimes interposed be a round head of one bone is received into a tween the articular surfaces of bones ; where cavity of another, and consequently is capathey fill up irregularities, that miglit other. ble of motion in all directions ; wise impede the motions of the part; and 2. Arthrodia ; where the cavity is more increase the security of the joint, by adapt- superficial, and much motion not allowed; ing the articular surfaces to each other, 3. Ginglymus ; where the motions are

The articular surfaces of bones are, in restricted to two directions, as in the hinge every instance, covered by a thin crust of of a door. cartilage, having its surface most exqui The skeleton consists of an assemblage of sitely polished, by which all friction in the all the bones in the body, excepting the os motions of the joint is avoided, and the ends hyoides. It is said to be a natural skeleton, of the bones glide over each other with the when the bones are connected by means of most perfect facility.

their own ligaments or cartilages ; an artifiNomenclature of bones. The processes or cial one, when wire or other extraneous apoplıyses of bones bear different names ac- substances are employed. cording to their figures. Hence we find It is divided into the head, trunk, and exthem described under the terms of head tremities. (roundish ball); condyle (a flattened head); The head consists of the cranium and the neck ; tuberosity ; spine ; &c. others have face. The former of these parts consists particular names from supposed resem- of 1 or 2 ossa frontis; 2 ossa parietalia ; blances.

1 os sphenobasilare; 2 ossa temporum; The cavities or depressions of bones are 2 mallei ; 2 incudes ; 2 stapedes; and 1 os called cotyloid, when deep; glenoid, when æthmoideum ; on the whole, of 13 or 14 shallow. Again, we have pits, furrows, bones. notches; sinuosities, fossæ, sinuses, foramina, The face has 2 ossa maxillaria superiora; and canals.

2 ossa palati ; 2 ossa malæ ; 2 ossa nasi; 2 ossa Connection of bones.-Anatomists have di lacrymalia ; 2 ossa turbinata inferiora; 1 os vided these into three classes ; Symphysis, vomer; 1 maxilla inferior; 32 teeth ; on the Synarthrosis, and Diarthrosis.

whole, 46 bones. The term symphysis merely denotes the The tongue has 5 ossa lingualia. union of the conjoined bones, without any The bones of the head are therefore 59 reference to peculiar form or motion; hence or 60; with the lingual bones 64 or 65. it is divided, according to the means by In the neck there are 7 cervical verte. which it is effected, into

bræ ; in the chest 12 dorsal vertebræ, 24 ribs,

2 or 3 bones of the sternum: in the loins The bones of the head are joined by 5 lumbar vertebræ ; in the pelvis 1 sacrum, sutures, a mode of union nearly peculiar to 1 ossa coccygis, 2 ossa innominata.

themselves; hence, when all the soft parts Therefore the whole trunk has 57 or 58 are destroyed by maceration, they still rebones.

main most firmly connected to each other, The shoulders have 2 clavicles and 2 sca excepting the front teeth and the lower pulæ; the arms 2 humeri; the fore-arms 2 jaw. The sutures are formed by numerous ulnæ and 2 radii ; the wrists 2 ossa navicu- sharp and ramified processes of the opposed laria ; 2 ossa lunata; 2 ossa cuneiformia ; edges of the different bones, shooting into 2 ossa orbicularia ; 2 ossa trapezia; 2 ossa corresponding vacuities of each other. In trapezioidea ; 2 ossa capitata ; 2 ossa unci some instances, however, the bones seem formia: the metacarpi 10 metacarpal bones : to be joined by the opposition of plane sur. the fingers 10 posterior phalanges ; 8 middle faces, and here the union appears externally phalanges, 10 anterior phalanges, and 8 se. like a mere line, instead of the irregular samoid bones.

zigzag course, which it takes in the former The bones of the upper extremities are case. The last mentioned junction is called in the whole 72.

harmonia. The tliighs have 2 femora: the legs 2 ti In the fætal state, the bones of the crabiæ, 2 patellæ, and 2 fibulæ : the tarsi 2 nium do not touch each other, but are seastragali

, 2 ossa calcis, 2 ossa navicularia, parated by considerable intervals of mem6 cuneiform bones, 2 ossa cuboidea : the brane, and have thin extenuated margins, metatarsi 10 metatarsal bones : the toes 10 which allow them to ride over each other posterior phalanges, 8 middle phalanges, when subjected to pressure. The larger · 10 anterior phalanges, and 6 sesamoid and more conspicuous of these intervals are bones.

called fontanelles, and allow of the pulsaThe bones of the lower extremities tion of the brain being felt in a young subare 66.

ject. The importance of this structure, in The whole skeleton contains 259 or 261 allowing the head to accommodate itself to bones.

the varying figure of the parts, through Of the bones just enumerated, the os fron- which it passes in the act of parturition, and tis, spheno-occipitale, ethmoideum, vomer, to sustain the violent pressure, which it exinferior maxilla, the vertebræ, sacrum, and periences in the same act, is sufficiently obos coccygis, the bones of the sternum, and vious. In the progress of ossification the the os linguale medium, are single bones; edges of the bones meet each other, and and being placed in the middle of the body, become united by the sutures. The use are consequently symmetrical. Of all the of these in the adult cranium, cannot be saother bones, there is a pair consisting of a tisfactorily asssigned ; nor do we see any bone for the right, and another for the left difference that would arise, if the head had side.

been composed of one piece only, without The structure of the whole skeleton is any suture. In old persons the sutures therefore symmetrical ; since an imaginary often become more or less generally obliteperpendicular line drawn through the whole rated. would divide even the single bones into a The individual bones are very firmly conright and a left half exactly resembling each nected by this mode of union, The edges other. This observation must however be of the different, bones overlap each other taken with some allowance; since the cor at different parts, so that they are mecharesponding bones of one side are not always nically locked together, and cannot be driperfectly similar to those of the opposite; ven in by any force ab externo. nor do the two halves of the single bones The bones of the cranium are composed always exactly agree in form, &c.

of two plates of cempact bony substance, The entire natural skeleton of a man of called the external, and internal or vitreous middle stature, in a dried state, weighs trom tables ; and an iniervening more or less ob150 to 200 ounces; that of a woman from vious reticular texture termed diploe. The 100 to 160 ounces.

proportion of these constituent parts varies Bones of the head.-The craninm is the

very considerably; the diploe is in no case óval bony cavity containing the brain; the of a very loose or open texture. The thick. face is placed at the anterior and lower ness of individual skulls is subject to great part of this cavity, and holds some of the variety; and there is much difference in organs of sense, and the instruments of mas. the various parts of the same skull. For tication.

the internal surface is every where exactly

moulded to the form of its contents, instead across it from one temple to another. It is of influencing them, as we might have ex. extremely irregular in its figure, and dipected a priori. Hence the convolutions vided into a body placed in the middle, two of the brain, the vessels, which ramify on alæ on the sides, and two pterygoid proits surface, &c. all leave prints on the inner cesses projecting downwards. table. The ordinary thickness varies from The os ethmoides occupies the middle of about the fifth of an inch to almost a mere the forepart of the basis cranii. It lies in line.

the interval between the two orbits, and The common number of the bones of the contributes to the cavity of the nose. It cranium is, as we have already stated, 7; but consists of an irregular assemblage of bony this is often increased by small portions cells, and processes of a very thin and deliformed between the others, and surrounded cate formation. It has a cribriform or horiby distinct sutures. These are called ossa zontal plate towards the brain ; a nasal or triquetra, or wormiana.

perpendicular plate; 2 turbinated bones; The form of the cranium is elliptical, and cells; and two orbital plates. pretty regularly so, particularly on the front, The sutures joining these are the coronal, upper and back part, and sides. The smal- between the os frontis and the two ossa paler circle of the ellipse is in front, and the rietalia; the sagittal, between the two ossa larger behind. It is tolerably smooth ex

parietalia ; the lambdoidal, joining the ossa ternally, except its basis, and it is almost parietalia to the os occipitis; the squamous, entire or unperforated, except at the same

between the temporal and parietal bones. part. In this situation, however, it possesses

The foramina occurring in the cranium, numerous holes, or as they are technically for the transmission of nerves are; 1, those named, foramina, which transmit blood-ves of the cribritorm plate of the ethmoid bone: sels to the brain, and the nine pairs of 2, f. optica : 3, f. lacera orbitalia : 4, f. ronerves, which arise from that organ.

tunda : 5, f. ovalia : 6, meatus auditorii inThe upper and lateral parts of the cranium terni: 7, f. lacera in basi cranii : 8, f. constitute a bony vault or arch, for protect- condyloidea anteriora : 9, foramen magnum. ing the brain ; this part is distinguished by Those which transmit blood vessels are ; the name of the skull cap.

1, canales carotici : 2, f. spinosa : 3, f. laIndividual bones of the head. The os

cera in basi cranii : 4, f. magnum. frontis forms the upper and anterior part of Bones of the face. --The ossa nasi consti. the skull; the eyebrow, and the roof of the tute the arch of the nose. The ossa lacyorbit.

malia or unguis are placed at the forepart of The ossa parietalia are called also ossa the inner edge of the orbits, and contain an bregmatis, since the fontanelles or breg. excavation which holds the lacrymal bag. mata are formed between their edges. They

The ossa malarum form the prominences compose the whole upper and most of the of the cheeks. lateral parts of the skull; and possess an ir

The ossa maxillaria superiora form the regularly quadrangular figure.

largest portion of the upper jaw, and most of The ossa temporum compose the lower the bony palate, or roof of the mouth; they part of the sides, and the middle of the basis contain also the upper teeth. of the cranium. They are divided into a The ossa palati form the back part of the squamous portion, a mamillary, and a pe- bony palate. trous portion. The former of these has a The ossa turbinata inferiora are situated process contributing to the zygoma, or bony in the cavity of the nose. arch, at the side of the cranium, under The former completes, with the nasal porwhich the temporal muscle passes. The tion of the ethmoid, the septum that divides second is also remarkable, by forming a the two nostrils. large nipple-like protuberance towards the The maxilla inferior is articulated to the basis cranii. The third, which projects basis cranii, and holds the lower teeth. into the cavity of the skull, contains the or The bones of the cranium and face comgan of hearing.

pose the two orbits, or pyramidal bony caThe os spheno-occipitale has generally vities, holding the organs of vision; to each been described as two bones. The occipi- of these, seven bones contribute. They tal portion forms the posterior portion of also form the cavity of the nose, which is the basis cranii, and a part also of the back very extensive, and includes portions of of the bony case.

nearly all the bones of the face, and some of The sphenoid portion is situated in the the skull. It has various cells, formed in the middle of the base of the skull, and extends bones of the skull and face, opening into it,

The teeth.These organs are composed to the Greek v. It consists of a body, two internally of a very hard bony substance; cornua, and two appendices, which are in and are covered externally by a still harder fact so many separate bits of bone. matter, called the cortex or enamel. -- The bones of the trunk consist of those of Each tooth has a body or crown, which is the spine, thorax, and pelvis. the part seen in the mouth; a neck, round The spine consists of twenty-four true or which the gum adheres ; and one or more moveable vertebræ; an os sacrum, and an fangs or roots, which are sunk in a process os coccygis (which indeed is composed of of the jaw, called the alveolar. These bo- four pieces): these last bones bearing condies are not formed in a nidus of cartilage, siderable resemblance to the vertebræ, are like bones, but on a soft vascular body, called sometimes the false vertebræ. called a pulp, which may be compared to Each vertebra has a body, which is situthe core, on which a horn is formed. This ated anteriorly, and consists of a cylindrical is surrounded by a delicate membrane called piece of bone; a perforation behind this, in the capsule of the tooth. When the teeth which the spinal morrow runs; two superior are being formed, these pulps and capsules and two inferior articulating processes, by with the rudiments of the teeth, are lodged which it is joined to the bone immediately in cavities hollowed out of the jaw-bone. above and below it; two transverse proThey afterwards rise, and, piercing the gum, cesses, and one spinous process, which proappear in the mouth.

jecting behind, forms a sharp ridge, from Teeth differ from other bones in possess which the name of spine has been applied ing no vessels nor nerves in their substance. to the whole column. As they are destined for the merely mecha. The vertebræ are divided into three clasnical function of triturating the food, such ses, according to their situation: the seven parts would not have heen suitable to this upper ones are called cervical: of these, the office. The pain of tooth-ach arises from first, that immediately supports the head, is a nerve, which, with a vessel, resides in a called the atlas; and the second, from a re'hollow, formed in the centre of the fang and markable bony process which it possesses, body of each tooth. These parts are ex

the vertebra dentata. The twelve next are posed by the decay. The teeth, in conse called dorsal vertebræ, and are distinguished quence of possessing no' vesse!s, are only by having the ribs articulated to them. The affected by chemical and mechanical causes. five last are called lumbar. These all differ They do not repair the effects of trituration, from each other is some circumstances. nor of accidental injury; nor do they suffer The most obvious distinction arises from the from any of the diseases, which affect other size: the upper ones are the smallest, and bones.

there is a gradual increase as we descend. There are two sets of teeth; the first are The column of the spine, when viewed fewer in number, and smaller in size; as they altogether, is not perpendicular; it stands fall out at a certain age, to make room for forwards in the neck, recedes in the upper other larger ones, they are called deciduous part of the back, and projects again in the or temporary. The second set lasts through- loins. Holes are left between the bones for out life, and are called the adult or perma- the transmission of the nerves which arise nent set.

from the spinal marrow. The latter consists of 32 teeth; 16 in The sacrum forms the back of the pelvis, each jaw. There are four incisores or cutand is hollowed out in front. In form it is ting teeth in front; 2 canini or cuspidati, or triangular, and the base is joined to the last dog teeth, placed one on each side of the for- vertebra. It is perforated by a canal, in mer; 4 bicuspides behind the last ; and 6 mo- which the termination of the medulla spinalis lares behind these. From the late period at is lodged. Its apex has connected to it the which the last molaris appears, it is called os coccygis. the dens sapientiæ, or wise tootli.

The thorax is formed by the twelve dorThe temporary set consists of twenty sal vertebræ, the ribs, and sternum. The teeth; ten in each jaw. There are 4 in- ribs are long, curved, flattened, and narrow cisores; 2 cuspidati; and 4 molares. bones, attached behind to the dorsal verte

The permanent teeth are lodged at first bræ both in their bodies and transverse in cavities of the jaw, near the roots of the processes, and joined in front to a piece of temporary ones; and as these last are shed, cartilage. They are twelve in number, and rise up to supply their places.

the seven upper ones, whose cartilages are The bone of the tongue is called os affixed to the sides of the sternum, are called byoides from its very accurate resemblance true ribs; the tive lower ones, tùe cartilages

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