io6 THE UPPER EXTREMITY 



muscles, and it anastomoses with the anterior terminal branch 

 of the inferior ulnar collateral artery. 



The a. recurrent ulnaris dorsalis (O.T. posterior ulnar 

 recurrent) passes medially, under cover of the flexor digitorum 

 sublimis, and then turns proximally, between the two heads 

 of origin of the flexor carpi ulnaris, to gain the interval 

 between the medial epicondyle of the humerus and the 

 olecranon on the dorsal aspect of the limb. Here it comes 

 into contact with the ulnar nerve, and anastomoses with the 

 posterior terminal branch of the inferior ulnar collateral artery 

 and with the superior ulnar collateral artery. 



It is not uncommon to find the two recurrent arteries 

 arising from the ulnar trunk by a short common stem. 



The arteria interossea communis is a short, wide trunk, 

 which takes origin immediately below the recurrent branches, 

 about an inch or so below the commencement of the ulnar 

 artery. It proceeds dorsally, and at the proximal margin of 

 the interosseous membrane it divides into two terminal 

 branches, viz. the volar (O.T. anterior] and the dorsal (O.T. 

 posterior) interosseous arteries. 



The arteries, carpece ulnares are two small arteries, which 

 partially encircle the wrist. The anterior ulnar carpal artery 

 runs laterally, under cover of the tendons of the flexor digi- 

 torum profundus, and anastomoses with the volar carpal 

 branch of the radial artery. From the arch thus formed 

 small twigs are given to the volar aspect of the carpal bones 

 and joints. The dorsal ulnar carpal artery gains the dorsal 

 aspect of the carpus by winding round the medial margin of 

 the limb immediately proximal to the pisiform bone, and 

 under cover of the tendon of the flexor carpi ulnaris. 



Nervus Ulnaris (Ulnar Nerve). The ulnar nerve, which 

 was traced in the dissection of the arm as far as the interval 

 between the olecranon and medial epicondyle of the humerus, 

 enters the forearm between the two heads of the flexor carpi 

 ulnaris. It proceeds distally, upon the flexor digitorum pro- 

 fundus and under cover of the flexor carpi ulnaris, along the 

 volar aspect of the medial side of the forearm. Close to 

 the wrist it becomes superficial, upon the lateral side of the 

 tendon of the flexor carpi ulnaris, and it reaches the palm by 

 passing anterior to the transverse carpal ligament. In the 

 proximal third of the forearm the ulnar nerve is separated 

 from the ulnar artery by an interval, but in the distal 



