Myogale extensor subsp. digitorum

WHIDDEN, HOWARD P., 2000, Comparative Myology of Moles and the Phylogeny of the Talpidae (Mammalia, Lipotyphla), American Museum Novitates 3294, pp. 1-53 : 26-27

M. extensor digitorum communis ( fig. 11 )

ORIGIN: By superficial, medial, and deep heads, all from the lateral epicondyle of the humerus.

INSERTION: Via three long tendons, each of which splits prior to insertion. The tendons of the superficial head insert on the medial surfaces of the distal phalanges of digits IV and V, those of the medial head insert on the dorsal surfaces of the distal phalanges of digits III and IV, and those of the deep head insert on the dorsal surfaces of the distal phalanges of digits II and III.

REMARKS: This muscle has the same general form in Condylura , Desmana , Galemys , Neurotrichus , Parascalops , Scalopus , Scapanus , Scaptonyx , Talpa , and Urotrichus . In Uropsilus , this muscle originates as just two heads, superficial and deep. The superficial head forms a tendon that splits to insert on the medial surfaces of the distal phalanges of digits IV and V, and the deep head forms a tendon that splits to insert on the dorsal surfaces of the distal phalanges of digits II, III, and IV. There may be individual variation in the insertion of this muscle, as some of the individuals I dissected appeared to have

slightly different patterns of tendon insertion. For example, in some specimens of Condylura , the tendon of the superficial head sent a branch to digit II, as well as to digits IV and V. Reed (1951) described only two heads for this muscle in Neurotrichus , a superficial head inserting on digit V, and a deep head inserting on digits I–IV. Also, although his description of this muscle for Scapanus is largely similar to mine, Reed stated that the deepest head inserts only on digit II.

M. extensor indicis et pollicis longus ( fig. 11 )

ORIGIN: From the proximal end of the posterior crest and from the lateral side of the proximal crest of the olecranon process of the ulna.

INSERTION: Via a tendon that splits to insert on the medial sides of the distal phalanges of digits I and II.

REMARKS: This muscle has the same general form in the 11 study taxa.

Figures

Fig. 11. Dorsal view of forearm muscles of Parascalops. A, Superficial muscles; B, deeper muscles.