Mogera flexor 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 : 30-31

M. flexor digitorum superficialis

ORIGIN: As a single head from the medial epicondyle of the humerus and from the adjacent surface of a massive ligament associated with M. flexor digitorum profundus.

INSERTION: Via a tendon that broadens in the palm superficial to the flexor profundus ligament, and then sends out branches to the proximal phalanges of digits II, III, and IV. These branches are perforated by the corresponding branches of the M. flexor digitorum profundus ligament.

REMARKS: This muscle has the same general form in Parascalops , Scalopus , Scapanus , and Talpa . In Condylura , Desmana , Galemys , Neurotrichus , Scaptonyx , Uropsilus , and Urotrichus , this muscle originates as three distinct heads, and these form separate tendons that insert on the proximal phalanges of digits II, III, and IV. These tendons are also perforated by the corresponding branches of the M. flexor digitorum profundus ligament. In Uropsilus , the three heads originate from the medial epicondyle of the humerus, and in Desmana and Galemys , they originate from the area between the trochlea

and the pit for the massive ligament associated with M. flexor digitorum profundus. In Condylura , Neurotrichus , Scaptonyx , and Urotrichus , the superficial head originates from the surface of the flexor profundus ligament, and the other two heads originate from the area between the trochlea and the pit for the ligament of M. flexor digitorum profundus. The three heads of this muscle are sometimes referred to as the condylo­ulnaris, centralis, and condylo­radialis (Howell, 1936; Reed, 1951). Reed (1951) named this muscle M. flexor digitorum sublimus. His treatment of it is similar to mine, except that he described the superficial head in Neurotrichus as originating from the medial epicondyle of the humerus.

M. flexor digitorum profundus

In Uropsilus , this muscle has five muscular heads, but in the other study taxa, a massive ligament has apparently replaced one of the heads. This flexor ligament originates from a prominent pit on the distal tip of the medial epicondyle of the humerus and receives contributions from the remaining muscular heads before splitting to insert on each of the five digits. Reed (1951) reported that Neurotrichus has five muscular heads to this muscle, but I found only four in the specimens of Neurotrichus that I dissected, and I believe that he was in error. I use Reed’s (1951) names for these muscles, but I come to different conclusions about the homologies of two of these muscles in Neurotrichus relative to the other taxa. Thompson (1884) was the first to describe the function of the flexor ligament.