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19-7 part IT. A N . A T O M Y. backfide of the os humeri, from its neck to the external The teres miner may turn Jie arm when deprefled . condyle. round its axis, from before outward; as it happens It is fixed above in the neck of the os humeri under when the fore-arm, being bent and applied to the lower the inferior furface of the great tuberofity, and under part of the bread, is removed from thence, without mo- the infertion of the teres minor, but a little more backving the elbow from the fide. ward. Jt is likewife fixed by fome oblique fibres in the external inter-mufcular ligament. Sect. V. The Muscles which move the Bones of th&. Fore-arm on the Os Humeri. ANCON7EUS IN TERN US. This mufele is fhorter and more flefhy than the’ anBICEPS five COR ACO-R ADI ALIS. externus, and lies toward the inner part of the Th i s is a double mufcle made up of two long fleftiy conaeushalf of the os humeri. bodies, more or lefs round, lying by the fide of each o- lower It is fixed above, under the lower extremity "of the ther, on the middle anterior part, and a little toward teres major, but a little more backward, and to the in the infide of the arm. Thefe two bodies are feparated ternal inter-mufcular ligament, which makes a kind of above, each of them endihg in a fmail tendon. As they feptum between this mufcle the •brachireus. From run down they become contiguous, and afterwards clofe- thence the fibres cohtratting inandbreadth, pafs toward the ly united by one common broad tendon. tendon of the anconteus major, fome of .them running in It is fixed by one of the fuperior tendons, in the apex between it and the bone, and are inferted in the edge of the coracoid apophyfis of the fcapula. The other fuperior tendon is fmaller and longer tl an and inner fide of that tendon. the former, and the flefhy body belonging to it ihorter ANCONTEUS MINOR. and more compounded. This tendon is lodged in the bony channel of the os humeri, being furrounded by a This is a firraii mufcle obliquely triangular/ lying in membranous vagina continued from the capfular liga- the oblong foflula on the. outfide of the olecranum. ment, and ending at the fiefliy body where it is entirely It is fixed by a fmall, but pretty ftrong rcridon, in the clofed. lower part of the external condyle of the os humeri. From thence the flefhy fibres run down obliquely in a ra'B R A D H I JE U S. diated form, and are inferted in the bottom and whole This is an oblong, thick, and broad mufcle, lying pofterior edge of the foflula already mentioned. immediately on the anterior part of the lower half of the os humeri. The upper part of it is- forked or doped, Uses of the Mufcles ’which move the Bones of the Foreand at the bending of the joint of the elbow the lower arm on the Os Humeri. part contracts. biceps, or coraco-radialis, bendsbothbor.es of It is fixed to the furface of the os humeri by a great theThe Fore-arm, and turns the radius upon the ulna ; pernumber of flefhy fibres, from the lower infertion of the forming motions by its infertion in the radius alone. deltoides, almoft down to the two fofii-e at the lower ex- It Hkewifebothmoves the os humeri cn the fore-aim, the tremity of the bone, and from one edge of the forefide fcapuia on the os humeri, and the os humeri on the fcaof this lower extremity to the other: The fibres are pula. for the moft part longitudinal, thofe neareft the furface The brachiasus ferves to bend the fore-arm on the os • of the mufcle being longeft, the more internal growing humeri, by its infertion in the ulna, and by the .congradually fhorter. nedion of that bone with the radius. It ferves alfo to move the os humeri on the fore-arm. ANCONEUS MAJOR. The anconteus maximus ferves to extend the fore-arm, by bringing the ulna to a ftraight line with the os huThisJs a long flefhy mufcle lying on the backfide of meri. It ferves likewife to extend the os humeri on the the ps humeri. when the lall named bone is fixed by fome exteIt is fixed above by a fhort tendon to the inferior im- ulna, rior refiftance, as when, being laid upon the ground, we preflion in the neck of the fcapula, and to a fmall part rife by fupporting ourfelves on our hand. In this cafe of the inferior cofta of that bone. From thence it-paf- likewife, fes between the extremities. of the fubfcapularis and te- brachialis.the fcapula mutt be kept fteady by the coracores minor, and, having reached the backfiue of the low- The two lateral anconaei co-operate with, and aflifl er extremity of the os humeri, it ends obliquely in a the anconaeus maximus, in extending the fore-arm on flrong broad tendon, which, adhering clofely in the capfular ligament, is afterwards fixed by a broad infertion the os humeri, and the os humeri on the fore-arm. The anconseus minimus may concur with the other in the rough tuberofity on the upper fide of the olecranum. mufcles of that name, in extending the fore-arm on the os humeri, and'the os humeri on the fore-arm ; but its ANCON ASUS EXTERN US. action does reach to all the degrees of flection of thefe This is a long mufcle lying on the outer part of the bones; for not when the fore-arm is very much, bent, if we Vol. I. No. 9. 3 3D examine
