OCR Text |
Show 1871.] MYOLOGY OF THE KINKAJOU. 551 inner border of the olecranon and fascia of the forearm. It receives about its middle a large slip from the dorsal portion of the panniculus. The latter muscle is also intimately associated with the teres major. The Paradoxurus typus and Dog have a similar arrangement. In the Caracal the dorsal panniculus is not so differentiated as in the preceding, and the Achselbogen is wanting. The triceps is large and exceedingly well-developed; the only point of note is that the representative of the anconeus is not segmented from the inner factor of the triceps, though in other respects disposed in the usual manner. The anconeus epitrochlearis is small in the Kinkajou and in the Paradoxurus typus; but in the Caracal it is larger and more elongated. It arises in the latter from the ridge above the internal humeral condyle in front of the epicondyloid foramen. It is only partly inserted into the anconeal process, the remainder of its fibres being continuous with the flexor carpi ulnaris. This muscle, in combination with the flexor carpi ulnaris, simulates on the inner side of the humerus the supinator longus on the outside. The deltoid consists of the two factors the mesodeltoid and post-deltoid, separated by an areolar interval. They present no remarkable features worthy of description. The supraspinatus and infraspinatus have the usual arrangement. The teres minor is represented by an unsegmented portion of the infraspinatus. The biceps arises by two heads-one the analogue of the so-called long head of human anatomy, and the other the short head. Both arise in conjunction from the base of the coracoid tubercle. The long head is very large; it passes through the capsular ligament of the shoulder-joint, grooving the humerus. The short head consists of a narrow elongated tendon, which occupies almost half of the entire length of the muscle ; it runs parallel with the long factor (after the latter has emerged from the bicipital canal) for some distance, then, passing in front of it, terminates at its distal extremity by blending with the anterior fibres of the long head. It is inserted into the radial tubercle. The short factor of the biceps gives origin to two varieties of the coraco-brachialis, viz. the short and the long. The coraco-brachialis brevis is an inverted-wedge-shaped muscle; it is inserted into the inner border of the neck of the humerus immediately above and extending somewhat behind the tendon of insertion of the teres major. The coraco-brachialis longus is a slender, elongated, wedge-shaped muscle; it arises from the tendon of the short head of the biceps, about half an inch below the preceding. The muscular fibres gradually taper into a tendon which occupies half the length of the entire muscle. It is inserted into the inner border of the humerus, immediately above the epicondyloid foramen. This is a remarkable example of the coexistence of the long and short varieties of the coraco-brachialis of Wood. The latter accurate observer has placed on record several similar examples occurring in the human subject. I have also found several similar specimens |