OCR Text |
Show 1885.] MYOLOGY OF THE WATER-OPOSSUM. 9 from both coracoid and glenoid, the gleno-ulnar arising from glenoid alone. The former is inserted into radial tubercle; the latter is inserted with brachialis anticus into coracoid process of ulna. Triceps.-Arises by three heads. Long one arises from lower part of posterior border of scapula, by tendon in its lower two thirds, and in its upper third by muscular fibres, which pass obliquely on to outer aspect and are inserted into tendon. Inner and outer heads partly separated by musculo-spiral nerve, arising from inner and posterior aspects of humerus, and from intermuscular septum separating outer head from brachialis anticus. Fibres from outer head pass obliquely into long head at its lower third, and partly into outer side of olecranon. Most of fibres of inner head are inserted into anterior part of long head, a few being inserted into inner side of olecranon. Long head is inserted into tip of olecranon. Anconeus internus.-Arises from back of internal condyle of humerus, and is inserted on inner side of tip of olecranon. Its upper fibres are continuous with inner head of triceps, being separated from it by ulnar nerve. Its lower fibres are separated from flexor carpi ulnaris by a fibrous septum. Anconeus externus.-Arises from back of external condyle of humerus. Inserted into outer side of olecranon and outer side of ulna for its upper fifth. Its upper fibres are continuous with outer head of triceps. Brachialis anticus.-Arises from outer side of humerus in its whole length. Inserted into ulna, just outside insertion of gleno-ulnar portion of biceps. Palmaris longus.-Arises by fleshy fibres from internal condyle of humerus and lower part of supracondyloid ridge. Inserted into flexor tendon in palm. Two portions of it are quite distinct from main mass-one, which arises from internal condyle, and whose tendon underlies principal tendon, is inserted into the lower part of it; the other leaves the inner side of the muscle and is inserted into the inner side of its tendon. Flexor carpi radialis.-A thin muscle arising from internal condyle of humerus. Inserted into radial side of base of metacarpal of medius. Flexor carpi ulnaris.-Arises from internal condyle of humerus, from posterior surface of olecranon, and from bridge between the two, closely connected with anconeus internus. Its superficial fibres form a thin belly inserted by a very thin tendon into base of metacarpal of minimus ; the remainder forms a strong tendon inserted into pisiform. Flexor digitorum profundus.-Consists of three parts all closely connected. Condylar portion, superficial, arising from internal condyle of humerus, closely connected with flexor carpi ulnaris. Ulnar portion, the largest, arising from upper third of ulna and outer surface of olecranon. Radial portion arises from upper third of radius, internal to oblique line. |