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Part I. 182 a N A T O M Y. round head of one bone plays in the orbicular focket of middle-finger being the longeft arid largeft.—Thofe of another ; only it is fomewhat more confined and lefs ex- the fore-finger come next to that in thieknefs, but notin peditious, but ftronger and more fecure, than fuch joints length, for thofe of the ring-finger are a little longer. The little finger has the fmallefl bones. Which difpofigenerally are. The fccond bone of the thumb has a large bafe form- tion is the beft contrivance for holding the largeft bodies; ed into an oblong cavity, whofe greateft length is from becaufe the longeft fingers are applied to the middle larone fide to the other.—Round it feveral tubercles may geft periphery of fuch fubftances as are of a fperical fibe remarked, for the infertion of ligaments.—Its body gure. is convex, or a half-round behind; but flat before, for The ufes of all the parts of our fuperior extremities lodging the tendon of the long flexor of the thumb, are fo evident in the common actions-of life, that it is which is tied down by ligamentous (heaths that are fixed needlefs to enumerate them here ; and therefore we (hall on each fide to the angle at the edge of this flat furface. proceed to the laft part of the fkeleton. The articulation and motion of the upper end of this fecond bone is as lingular as that of the former,!—For its cavity being joined to the round head of the firft bone, OF THE INFERIOR EXTREMITIES. it would feem at firfl: view to enjoy motion in all di- The Inferior Extremities depend from the aredtions; yet, becaufe of the (Irength of its lateral liga- cetabula of the offa innominata; are commonly divided ments, oblong figure of the joint itfelf, and mobility of into three parts, viz. the thigh, leg, and foot,. the firfl: joint, it only allows fledtion and extenfion; and The Thigh -has only one bone ; which is the longeft of the body. The fituation of it is not perpendicular ; thefe are generally much confined. The third bone of the thumb is the fmallefl, with a for the lower end i$ inclined, confiderably inwards : So large bafe, whofe greateft extent is from one fide to the that the knees are almoft contiguous, while there is a other. This bafe is formed into two cavities and a confiderable diftance between the thigh-bones above : middle protuberance, to be adapted to the pulley of the Which is of good ufe to us, fince fufficient fpace is thereforlner bone. Its body is rounded behind; but is by left for the external parts of generation, the two great flatter than in the former bone, for fuftaining the nail.— cloacE of urine and fceces, and for the large thick mufr It is flat and rough before, by the infertion of the flexor cles that move the thigh inwards : And, at the fame tertii internodii. This bone becomes gradually fmal- time, this fituation of the thigh-bones renders our proler, till near the lower end, where it is a little enlarged, greflion quicker, furer, ftreighter, and in lefs room. The upper end of the thigh-bone, is not continued in a and has an oval fcabrous edge. The motion of this third bone is confined to fledtion (freight line with the body of it, but is fet off obliquely inwards and upwards, whereby the diftance here between and extenfion. The orderly difpofition of the bones of the fingers in- thefe two bones at their upper part is confiderably irlto three rows, has made them generally obtain the name creafed. This end is formed into a large fmooth of three phalanges. All of them have half-round round head, which is the greater portion of afphere-unconvex furfaces, covered with an aponeurofis, formed by equally divided. Towards its lower internal part, a the tendons of the extenfors, lumbricales, and interoflei, round rough fpongy pit is obfervable, where the ftrong and placed diredtly backwards, for their greater ftrength ; ligament, commonly called the reaW one, is fixed, to and their flat concave part is forwards, for taking hold be extended from thence to the lower internal part of more furely, and for lodging the tendons of the flexor the receiving cavity, where it is confiderably broader mufcles.The ligaments for keeping down thefe than near to the head of the thigh-bone. The fmall tendons are fixed to the angles that are between the con- part below the head, called the cervix, of the 6s femoris, has a great many large holes, into which the fibres of the vex and concave fides. The bones of the firfl phalanx of the fingers anfwer ftrong ligament, continufed from the capfular, enter, and to the defeription of the fecond bone of the thumb : on- are thereby furely united to it; and round the root of ly that the cavity in their bafe is not fo oblong; nor is the neck, where it rifes from the bone, a rough ridge is their motion on the metacarpal bones fo much confi- found, where the capfular ligament of the articulation itBelow the back-part of this root, ned ; for they can be moved laterally or circularly, but felf is connedted. have no rotation, or a very fmall degree of it, round their the large unequal protuberance, c&Wci: trochanter major, (lands out; the external convex part of which is diftinaxis. The fecond bone of the fingers has its bafe formed guiflred into three different furfaces, whereof the one on into two lateral cavities, and a middle protuberance; the fore-part is fcabrpus and rough, for the infertion of while the lower end has two lateral protuberances, and a the glutseus minimus; the fuperior one is fmooth, and middle cavity; therefore it is joined at both ends in the has the glutasus medius inferted into it; and the one befame manner, which none of the bones of the thumb are. hind is made flat and fmooth by the tendon of the gluThe upper edge of The third bone differs nothing from the defeription of •tasus maximus palling over it. the third bone of the thumb, excepting in the general this procefs is (harp and pointed at its back-part, where diftinguhhing marks ; and therefore the fecond and third .the glutjeus medius is fixed; but forwards it is more-obphalanx,of the fingers enjoy only flection and extenfion. tufe, and has twm fuperncial pits formed in it: Into the All the difference of the phalanges of the feveral fin- fuperior of thefe, -the piriformis is implanted; and the gers confifts in their magnitude. The bones of the obturator internus and gemini are fixed into the lower
