406 JAMES CRAWFORD WATT 



2. Flexor carpi ulnaris (figs. 7 and 8, F.C.U.) 



Origin. A broad, flat, fleshy origin from the front of the 

 medial epicondyle of the humerus and from the surface of the 

 bone in front of and below this. 



Insertion. This muscle is by far the largest of all those yet 

 described in the forearm. It is fleshy to about two-thirds the 

 distance down the radius where it narrows into a heavy tendon" 

 which inserts at the lower end of the radius and into the carpus. 



Second layer 



S. Flexor digitorum sublimis (superficial portion) (fig. 8, F.D.S.) 



Origin. Under the origin of the flexor carpi radialis as a 

 thin flat fleshy muscle which courses obliquely to join one of the 

 deep muscles arising on the radius, which will be described 

 later. 



This I would homologise with the flexor digitorum sublimis 

 due to its position as the second layer of muscles from the 

 medial humeral epicondyle. There is a possibility of this 

 muscle being the humeral portion of the pronator radii teres. 

 Against this latter view, are the facts that the muscle is entirely 

 covered by the two carpal flexors, and that it is not inserted 

 into the shaft of the radius but joins a muscle arising here to be 

 inserted into the carpus. 



DEEP MUSCLES 



Third layer 

 4. Flexor digitorum profundus (figs. 7 and 8, F.D.P.) 



Origin. A thick fleshy muscle arising from the lower two-thirds 

 of the volar aspect of the radius on its lateral (apparently dorsal) 

 portion. 



Insertion. This muscle passes as a compact fleshy bundle 

 as far as the metacarpal region where it condenses into its ten- 

 don which is single and runs on the volar aspect of the single digit 



