THE LIMBS OF THE HOUSE 41 



M. flexor carpi radialis. — The radial flexor of the carpus runs 

 parallel with the medial border of the radius. Its origin is from the 

 medial epicondyle of the humerus close to the articular margin and 

 immediately behind the point of attachment of the medial collateral 

 ligament. In the distal third of the forearm a rounded tendon replaces 

 the elongated fusiform fleshy belly of the muscle. The tendon, enclosed 

 in a synovial sheath, traverses a canal in the ligament at the medial 

 border of the carpus and is inserted to the base of the second meta- 

 carpal bone. 



M. flexor carpi ulnaris. — The ulnar flexor of the carpus possesses 

 two heads : (1) The humeral head (caput humerale) is strong and 

 arises from the medial epicondyle of the humerus behind the origin 

 of the radial flexor with which it is intimately connected. (2) The 

 ulnar head (caput ulnare) is weak, flattened, and narrow, and springs 

 from the medial surface of the olecranon of the ulna. The two heads 

 unite in the proximal third of the forearm. 



The strong tendinous insertion of the muscle is to the accessory 

 carpal (pisiform) bone. 



Dissection. — In order to obtain a satisfactory view of the flexors of 

 the digits, it is necessary to reflect the ulnar flexor of the carpus. 



M. flexor digitorum sublimis. — The superficial flexor is a strong, 

 largely tendinous muscle of irregularly triangular outline in section. 

 Its origin is from the medial epicondyle of the humerus in common 

 with the deep flexor. Near the carpus a powerful tendon begins, and, 

 passing down the groove-like volar (posterior) surface of the carpus 

 under cover of the transverse ligament, is continued into the meta- 

 carpus. The further course of the tendon will be followed later. 



From an impression on the volar (posterior) surface of the radius, 

 at about the junction of the middle and distal thirds and close to the 

 medial border of the bone, a strong tendinous band (caput tendineum) 

 arises and joins the tendon of the superficial flexor about the level of 

 the radiocarpal articulation. 



M. flexor digitorum profuxdus. — The deep flexor is by far the 

 largest and most powerful muscle in the region now being examined. 

 Three heads can readily be distinguished : 



1. Caput ulnare. — The ulnar head belongs to the most superficial 

 layer of muscles behind the radius, where it will be found along the 

 posterior border of the ulnar extensor of the carpus. Arising from the 

 medial surface and posterior border of the olecranon, the fleshy portion 

 of the ulnar head about the middle of the radius gives place to a 

 narrow, rounded tendon, which passes down the forearm under the edge 



