| OCR Text |
Show 304 MR. R. H. BURNE ON THE [Apr. 18, Subscapularis (text-figs. 59, 60, & 62. 52).-Origin : from the whole length of the outer surface of the scapula and partly also from the anterior and posterior surfaces. Insertion: along the extensor surface of tlie humerus from the median process to the origin of the anconseus. Fiirbringer gives an origin also from the inner surface of the scapula. A muscle (text-figs. 60, 62, & 64. 52 a) I was unable to determine, but probably a separate part of the subscapularis. Origin : from the posterior surface of the scapula (except its dorsal third). It passes behind the outer end of the coracoid, and is inserted between the median process and the head of the humerus. Anconceus. Pars anconaeus liumeralis (text-fig. 62. 53).- Origin: from the distal half of the extensor surface of the humerus. Insertion : upon the head of the ulna. Fiirbringer speaks of this muscle as taking origin equally from both sides of the humerus. In my specimen, the flexor surface of the humerus was occupied by the origin of the humero-radialis longus dorsalis, Humero-radialis longus dorsalis (text-figs. 63 & 64. 55).-A large but thin sheet of muscle that arises from the radial half of the flexor surface of the humerus distal to the lateral process, and extends on the radial side of the forearm to the wrist. The surface of the muscle is covered by a layer of dense connective tissue, but by cutting this away three fairly distinct muscle-bellies can be made out. From the ulnar side these are : (1 ) a part united by fibrous tissue to the tendon of the biceps, and inserted just to its radial side upon the head of the radius; (2) a part extending down the flexor surface of the radius and inserted about its middle; (3) a part closely applied to the outer border of the anconasus, and inserted upon the whole of the radial and part also of the extensor surface of the radius down to the wrist. Humero-carpali-metacarpalis I. (text-figs. 62 & 63. 56).-Origin : from the outer condyle of the humerus, between the anconfeus and the humero-radialis longus dorsalis. Insertion : upon the head of metacarpal I., and to the back of the hand by a tendinous expansion that runs diagonally towards the little finger. Hoffmann gives an insertion for this muscle in other Chelonia upon the radius and carpus. TJbia-carpo-radialis + Carpali digiti I.-Y . dorsalis (text-figs. 62 & 63. 60 + 61).-Origin: from the inner surface of the ulna, from the ligaments of the extensor surface of the wrist, and from the greater part of the extensor surface of metacarpals I.-IV. Insertion : by a slip into the head of metacarpal I., and by flat tendons into the distal phalanges of digits I.-IV. and into metacarpal Y. This is a thin muscle-sheet of very degenerate character, especially towards the ulnar side of the hand. Its tendons are bound closely to the periosteum of the finger-bones and can have little or no play. It corresponds fairly to" the above-mentioned muscles of Hoffmann. The part proper to digit Y. forms, however, a |
