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Show 868 MR. ST. GEORGE MIVAKT ON THE [DeC. 6, The brachialis anticus (figs. 1, 13, 16, B.A) occupies the whole antero-extemal aspect of the humerus, extending upward as far as the insertion of the deltoid. On its outer side it has the external head of the triceps ; and on its inner side it has the biceps, the short part of the coraco-brachialis, and the insertion of the pectoralis. Passing downward (and much uniting on its ulnar side with the biceps, which wraps it round anteriorly) it is inserted into the flexor surface of the ulna, just below its articular surface for the humerus, and between the tendons of insertion of the biceps. Its insertion is conterminous (fig. 16) with the upper part of the ulnar origin of the flexor longus digitorum. Supinator longus* (figs. 1, 9, 11, & 15, S. L ) . This muscle is very large, but not so distinctly double as in the Iguana. Its more superficial portion arises from the external condyle, and is inserted into the outer side of the radius for almost its whole length. Its deeper portion springs from quite the lower end of the humerus, external to its articulation with the radius. It is inserted into the upper half of the extensor surface of the radius. The superficial part is closely connected, toward and at its origin, with the extensor carpi radialis longior, but is separated from it distally by the extensor ossis metacarpi poliicis. Ulnad it is conterminous with the insertion of the pronator teres. The deeper part is not only intimately united with the extensor carpi radialis longior, which covers it, but also with the long part of the extensor ossis metacarpi poliicis. Outer surface of right scapula and upper arm. B. Biceps. B.A. Brachialis anticus. Dl & D2. Deltoid. L. Levator clavi-cube. 0. H. Omo-hyoid. P. Pectoralis. S1 & S2. Suprascapular.**. 8. C Subclavius. S. M. Serratus magnus. T. & T2. Triceps. Tr. Trapezius. Extensor carpi radialis longiorf (figs. 1, 9, & 11, E. R. Ii). This muscle arises by tendinous fibres from the outer surface of the external condyle superficially to the long portion of the supinator longus, * Meckel, I. c. p. 367. f Meckel. /. c. p. 381. |