110 U.S. NATIONAL MUSEUM BULLETIN 2 73 



long and narrow muscular belly changes into a round tendon, thinner 

 than that of the radial flexor of the carpus, at about the middle of 

 the forearm. It runs along the midventral line of the limb, passes 

 superficially to the flexor retinaculum and ends by expanding fanwise 

 and mingling with the central part of the palmar aponeurosis. 



Connections of this muscle with either of the two carpal flexors 

 appear to be common. I found the flexor carpi radialis sending once 

 a tendinous contribution to the palmaris longus (vide supra) and 

 Sirena (1871) describes one case where the latter muscle received 

 tendinous fascicles from each of the carpal flexors in the right side. 



Nerve supply: A branch of the median nerve enters the muscle 

 in the antecubital fossa. 



Function: Flexes the hand. 



SUPERFICIAL SERIES, ULNAR DIVISION 



M. flexor carpi ulnaris: It is found medial to the palmaris longus 

 and has a double origin. Fleshy fibers arise from the lower border of 

 the ulnar epicondyle adjacent to those of the palmaris longus (fig. 

 27). They are joined by another group of similar fascicles coming 

 from the medial border of the olecranon and ulnar shaft as far down 

 as the distal third of the bone (fig. 27). The muscle also receives 

 fibers arising from the medial antebrachial intermuscular septum. 

 They all pass distally, forming a large and anteroposteriorly flattened 

 belly on whose deep aspect we find the ulnar artery and nerve as 

 they run toward the hand. Bundles from the distal third of the ulna 

 are separated from the rest, forming an apparently separate head. 

 The fibers of the flexor carpi ulnaris end on a central tendon formed 

 inside the muscle in the distal fifth of the forearm. It is short and 

 attaches to the proximal surface of the large pisiform. Sirena (1871) 

 also notes the double origin of the muscle, but he does not say what 

 length of the ulna is taken up by its fibers. Grand (1967) agrees also 

 as to its robustness. 



Nerve supply: The ulnar nerve sends a proximal branch to the 

 upper part of the muscle, and the dorsal carpal branch supplies a 

 smaller twig to the slip from the distal third of the ulna. 



Function: A powerful flexor of the carpus. 



M. epitrochleo-anconeus (fig. 28): This small and well-defined 

 muscle was found in both sides of my four specimens. It bridges the 

 distance between the dorsum of the ulnar epicondyle and the medial 

 surface of the olecranon as a muscular arch underneath which the 

 ulnar nerve passes into the forearm. Sirena (1871) also notes its 

 presence. 



Nerve supply: The ulnar nerve innervates the muscle through a 

 short branch that also goes to the joint. 



