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2C2 ANATOMY. Part IT. ] owe ft third part of the ontfide of the ulna, below the and do not lie fo much between the bones. The tendon infertion of the extenfor pollicis, and it has likewife a of the firft is inferted in the fide of the firft phalanx of fmall adhefion to the interofteus ligament. From thence the fore-finger, next the little finger, and in the correit runs down, ending in a diftinft tendon, without any fponding edge of the extenfor communis. The tendon communications, which having pafled through the annu- of the fecond goes in the fame manner to the fide of the lar ligament of the extenfor communis, afterwards joins ring-finger next to the thumb ; and the third, to the that tendon which goes to the index. fame fide of the little finger. There are therefore two external intercflei for the middle finger, one for the ring finger, but none for the EXTENSOR MINIMI DIGITI PROPRIUS, fore and little finger. The middle finger has no internal This is a kind of collateral or auxiliary mufcle of interoffeus; but the index, ring finger, and little finger, the extenfor communis, of which it appears almoit al- have each of them one. ways to be more or lefs a portion. It is fixed along the fuperior external half of the ulna, from whence its long fmall tendon runs down in SEMI-INTEROSSEUS INDICIS. company with the fourth tendon of the extenfor commu- This is a fmall, fhort, flat, flefby mufcle, very like nis, all the way to the little finger, where it joins it, and the antithenar, or internal femi-interoffeus of the thumb. It is fituated obliquely on one fide of that of the thumb, is infer ted with it. between the firft phalanx thereof, and the ftrft metacarpal bone. LUMBRICALES. It is fixed by one end to the outfide of the bafis of These are four very fmall flender mufcles, lying in the firft phalanx of the thumb, and a little to that bone the hollow of the hand, in the fame direction with the of the carpus by which this phalanx is fupported; and. perforatus and perforans. by the other end it is fixed near the head of the firft They are fixed, by their flefhy bodies, to the tendons phalanx of the index, on that fide next the thumb. of t}ie perforatus on the fide next the thumb, near the large annular ligament of the carpus. Near the heads HYPOTHENAR MINIMI DIGITI. of the metacarpal bones, they become very thin tendons, which accompany thofe of the perforans through the fur- This is a fmall and pretty long mufcle, lying on the css of the aponeurofis palmaris. Then they pafs on to backfide of the fourth metacarpal bone oppofite to the the fame fides of the firft phalanges, and join the ten- thumb, where, together with the metacarpius, or hypodons of the extenfor communis; each of them being thenar metacarpi, it forms that large eminence over-aconnedted with the neareft portion thereof, at the articu- gainft the thenar or that of the thumb. lation of the firft phalanx with the fecond. It is fixed by one end in the os orbiculare of the carpus, and a little to the neighbouring part of the large annular ligament. The other end terminates by a fhort INTEROSSEI. ftattifh tendon, fixed to that fide of the bafis of the firft These are fmall mufcles, lying between the metacar- phalanx of the little finger which is turn^f from the pal bones, and filling the three interftices left between thumb. them, both exteriorly, or towards the back of the hand, and interiorly, or toward the palm of the hand. Fiom Uses of the Mufcles •which move the Fingers. this firuation they have the name of intt.rr,ffei, and have been divided into external and internal. They are com- The perforatns ferves to bend the fecond phalanges monly reckoned fix in number, three external, and three of all the fingers except the thumb; and the particular mufcles, of which it is made up, may a<ft feparately, by internal. The firft two external interoflei are for the moft part reafon of their diftincft infertions in thefe phalanges. inferred in the middle finger. They fill the interftices They not only bend the fecond phalanges on the firft, between the three firft metacarpal bones, and furround but alfo the firft on the metacarpal bones, and the metathe middle bone all the way to the hollow of the hand. carpus and carpus on the fore-arm. Their tendons are fixed in both fides of the firft: phalanx, The perforans bends particularly the third phalanges and in both iides of the fecond tendon of the extenfor in which it is inferted; and by the fame motion it may likewife bend the firft and fecond phalanges. communis. The third external interoffeus lies in the interftice be- It may likewife be efteemed an afliftant to the ulnaris twixt the two laft metacarpal bones, and is moft com- and radialis interni in great efforts; and thefe mufcks monly inferted in the ring finger; its tendon being fixed many reciprocally be looked upon as affiftants to the perin that fide of the firft phalanx fartheft from the thumb, foratus and perforans. and in the correfponding edge of the third tendon of the The extenfor digitorum communis ferves to extend extenfor communis. The flefhy body of this mufcle the four fingers, to keep them in any degree of extenruns in between the two bones toward the hollow of the fion, and to moderate their flexion in all the determinate hand. degrees of a&iort of the perforatus and perforans. The internal interoffei are more fimple than the former. Each tendoa ferves to extend a whole finger, that all is,
