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Show 282 PROF. ST.-GEORGE MIVART ON THE [Feb. 21, The subscapularis is a strong muscle arising from the cartilage of the first rib, and inserted into the outer part of the clavicle. The deltoid has a distinct clavicular portion, as well as that from the metacromion and fascia investing the infraspinatus. The supraspinatus, infraspinatus, teres major, teres minor, and subscapularis are as in the Agouti1. The biceps has the usual two heads and radial insertion. The coracobrachialis consists of two parts-one descending to the middle of the humerus, the other down to the internal condyle. The brachialis anticus takes origin from the back of the summit of the shaft of the humerus, from the whole of its outer side, and from its lower front part. It is inserted into the radial side of the ulna by a strong tendon. The triceps has the usual three heads and the normal insertion. The supinator longus is very distinct, arising by delicate fascia from the external condyloid ridge between the summit of the origin of the extensor carpi radialis longior and the brachialis anticus. It is inserted into the outer side of the styloid process of the radius. The supinator brevis arises from the annular ligament and shaft of the radius as usual, and extends about halfway down the radius. The pronator radii teres is a very strong muscle, and very tendinous beneath. It arises as usual from the internal condyle, and is inserted into the radius from its middle to its distal end. The flexor carpi radialis extends from the internal condyle to the proximal phalanx of the index. "The flexor carpi ulnaris springs from the internal condyle and the olecranon, and is inserted into a large sesamoid on the outer side of the base of the carpus. The palmaris longus is very adherent to the muscle last described. It arises from the internal condyle, and is inserted into a cartilaginous palmar disk. The flexor sublimis digitorum is an exceedingly small muscle. It arises from the internal condyle. Near the wrist its tendon expands into a fascia which covers the palm. The flexor profundus digitorum and longus poliicis consist of four fleshy bellies: the first of these (the deepest and largest) springs from the ulna and interosseous membrane and the proximal part of the radius; one part takes origin from the distal half of the flexor surface of the radius; the third and smallest part comes from the internal condyle ; while the fourth part arises from the proximal part of the flexor surface of the ulna. These bellies end in a common tendon, which divides and goes to the five digits. There are three lumbrical muscles, as in the Agouti3. The pronator quadratus extends over the lower (distal) half of the radius and ulna. The extensor carpi radialis longior has a rather extensive origin from above the external condyle, quite distinct from that of the extensor carpi radialis brevior. It goes to the index, as usual. 1 See P. Z. S. 1866, p. 399. 2 L. c. p. 403. |
