1, Long extensor of the forearm (supplementary or accessory muscle of the latissimus dorsi); 2, radialis muscles (anterior extensor of the metacarpus); 3, tendons of extensor ossis metacarpi pollicis extensor primi internodii pollicis united (oblique extensor of the metacarpus); 4, tendon of extensor communis digitorum (anterior extensor of the phalanges); 5, strengthening band from the suspensory ligament of the fetlock; 6, internal surface of the radius; 7, flexor carpi radialis (internal flexor of the metacarpus); 8, anterior ulnar (oblique flexor of the metacarpus); 9, pisiform bone; 10, 10, tendon of the superficial flexor of the digits (superficial flexor of the phalanges); 11, 11, tendon of the deep flexor of the digits (deep flexor of the phalanges); 12, sesamoid prominence; 13, suspensory ligament of the fetlock; 14, internal rudimentary metacarpal.] The anterior ulnar arises above from the epitrochlea and the olecranon; thence it is directed towards the carpus, to be inserted into the pisiform bone. It proceeds therefore from the inner side of the elbow to the outer side of the upper part of the hand; it consequently crosses the posterior surface of the forearm obliquely. This is why, as we have pointed out above, it receives the name of the oblique flexor of the metacarpus. It is not unprofitable to recall in this connection that there is an internal flexor of the metacarpus, which is the flexor carpi radialis; and an external flexor of the metacarpus, which is the posterior ulnar (in human anatomy, extensor carpi ulnaris). It is between these two muscles that we find the oblique flexor--the anterior ulnar which we have just been studying. This muscle flexes the hand on the forearm. =Superficial Flexor of the Digits= (_Flexor digitorum sublimis_) (Fig. 76, 12; Fig. 77, 10, 10).--This muscle arises from the epitrochlea; thence it passes towards the hand, becomes tendinous, passes in a groove on the posterior aspect of the carpus, and terminates on the palmar surface of the phalanges in furnishing a number of tendons proportioned to the digital division of the hand. Whatever the number, to which we will again refer, each tendon is attached to the second phalanx, after bifurcating at the level of the first, so as to form a sort of ring, destined to give passage to the corresponding tendon of the deep flexor. This ring and this passage have gained for the muscle the name of _perforated flexor_. In the dog and the cat the principal tendon is divided into four parts, which go to the four last digits. In the ox it is divided into two parts only; as, moreover, in the pig, whose superficial flexor is destined for the two large digits only, the lateral digits receiving no part of it. Finally, in the horse the tendon is single.