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 195 Part II. ANA T O M Y. when the trapezius and ferratus major ceafe to aft ; by an aponeurofis, which, joining that of the biceps, is drawing downward the apophyfis coracoides, in which it fpread over the mufcles of the arm. is inferted. The fubclavius can have no other ordinary ufe, but to LATISSIMUS DORSE bring down the clavicula, after it has been raifed, toge- This is a broad, thin, and moftly flefhy mufcle, lying ther with the acromium, by the adlion of the trapezius between the axilla, where it is very narrow, and the and ferratus major. back on which it expands itfelf by radiated fibres, both in length and breadth, from the middle of the back all way to the lower part of the regio lumbaris; and Sect. IV. The Muscles which move the the from this fituation it has its name. Os Humeri on the Scapula. Its infertions are partly tendinous, and partly flefhy. In the firft place, it is fometimes, but not always, fixed D E L T O I D E S. in the inferior cofta of the fcapula near the angle, by a of flefhy fibres. In the next place, it is fixed This is $ very thick mufcle, covering the upper part fafciculus by an aponeurofis, in the fpinal apophyfes of the fix or of the arm, and forming what is termed the. flump of the feven, eight loweft vertebrae of the back, flioulder. It is broad above, and narrow below, in a in thofeandof fometimes all the vertebrae of the loins, in the fuperior triangular form ; and its name is taken from the refem- fpines and lateral parts of the os facrum, and. in the exblance it bears to the Greek letter A delta. It is made up of eighteen or twenty fmall fingle muf- ternal labium of the pofterior part of the os ilium. cles, in an oppofite fituation with refpe<S to each other, TERES MAJOR. and united by middle tendons ; fo that, taken all together, they form feveral penniform mufcles. The outer furface This is a long, thick, flat mufcle, fituated a little appears almoft wholly flefliy, but on the inner furface we obliquely between the inferior angle of the fcapula, and fee the feveral tendons. arm. Above, it is fixed in the whole inferior labium of the the upperfixedpartbyofitsthepofterior flefhy extremity in all the fpina fcapulae, in the convex or long edge of the acro- largeIt isangular on the outfide of the fcapula, in the mium, and in the third part of the anterior edge of the inferior colta offurface that bone, and near the. angle. From clavicle next that apophyfis. It furrounds the angle thence it advances with longitudinal fibres toward the upformed by the articulation of thefe two bones, by a par- per quarter of the os humeri, terminating in a broad ticular flope and fold contrived for that purpofe. flat tendon intermixed with fome fiefhy which at From thence it runs down above one third of the upper edge are continued all the way fibres, to the infertion, length of the os humeri, where it is inferred, by a thick the lying in the fame place with the tendon. tendon, in-the large mufcular rough impreflion below the It is inferted, by. its anterior extremity, at the lower bony ridge which goes from the great tuberofity of the part of the bony ridge of the fmall tuberqfity, along the head of the bone. edge of the channel, almoft oppofite to, and fometimes a little lower than the infertion of the peftoralis major. It PECTORALIS MAJOR. lines the cavity of the channel by a tendinous elongation, This is a large, thick, and flefhy mufcle, covering which joins that from the petftoralis, and feems to be the fore-part of the breafl, from the fternum, where it continued with it. is very broad, to the axilla, where it contrails in its pafTERES MINOR. fage to the arm. The infertions in the fternum end by a great number This is. a very flefhy mufcle, refembling the t^res of very Ihort tendons which run toward the middle of major, but narrower It lies above the laft the bone,' meeting and decuflating thofe from the fame named mufcle, betweenanddiefhorter. cofta inferior of the fcapula, mufcle on the other fide. The lower Infertions are and the head of the os humeri. moft diflinilly digitated, and they mix with thofe belong- It is fixed by one end to all the middle part of the ining to the reilns and obliquus externus of the abdomen, ferior cofta of the fcapula, and to the long particular furthere being likewife feveral fafciculi of fibres common to face immediately that cofta, reaching from the the peftoralis with thefe mufcles. This portion is alfo fix- great angular furfaceabove the neck of the bone. From ed to the ribs by internal flelhy ftrata covered by die ex- thence it runs wholly near fiefhy, it changes into a.flat tenternal infertions, and forming, together with them, the don, which is inferted in thetillpofterior or inferior furface thicknefs of the mufcle. of the great tuberofi ty of the head of the bone, and like From thence all the flelhy fibres contrail in breadth, wife a little lower down. and appfcoach each other, in their paffage to- the arm. The fuperior fibres run downward, joining thofe of the INFRASPINATUS. clavicular portion ; thofe next them run lefs obliquely ; the following more or lefs tranfverfely; and the inferior This is a triangular, flefhy, and pretty broad mufcie,. run upward, in the fame manner. in fome meafure penniform, filling the whole infra-fpiual. This mufcle, together with the deltoides, fends off cavity or fofia of the fcapula. It,