EEGIONAL ANATOMY 



21 



Action. — This muscle flexes the second phalanx on the 

 first, the first on the metacarpus, and the entire foot on the 

 forearm. Mechanically, it acts as a stay when the animal 

 isjstanding by maintaining the metacarpo-phalangeal angle. 



The Flexor Pedis Perforans, or the Deep Flexor of 

 THE Phalanges. — This muscle consists of three easily- 

 divided portions : an ulnar, a humeral, and a radial, and has 



Fig. 13. — Median Section of Foot. 



A, Os sutfraginis ; B, os coronte ; C, os pedis : D, navicular bone ; U, tendon 

 of the extensoi' pedis ; F, insertion of the extensor pedis into the 

 pyramidal process of the os pedis ; (t, the tendon of the flexor perforatus ; 

 JI, insertion of perforatus into the os coronte ; /, tendon of the flexor 

 perforans ; J, its passing attachment to the os coronse ; K, its final 

 insertion into the semilunar crest of os pedis ; a, section of coronary 

 cushion ; b, section of plantar cushion ; c, semilunar sinus of os pedis. 



for points of origin the olecranon process of the ulna, the 

 inner condyloid ridge of the humerus, and the posterior sur- 

 face of the radius. These portions are continued by a common 

 tendon which enters the carpal sheath with the tendon of 

 the perforatus, and continues with it through the synovial 



