364 A MANUAL OF ANATOMY 



arising from the internal epicondyle of the humerus, and beneath the deep 

 fascia, though it may be superficial to it. In such cases the common inter- 

 osseous is a branch of the main trunk, and it furnishes the anterior and 

 posterior ulnar recurrent arteries. (2) The artery, though normal in origin, 

 may pass superficial to the muscles arising from the internal epicondyle. 



Second Part of the Ulnar Artery. — The second part lies upon the 

 anterior annular ligament, and extends from its upper to its lower 

 border. It has a vena comes on either side of it, and the ulnar 

 nerve on its inner side. It lies on the outer side of the pisiform 

 bone, by which it is overhung, and on the inner side of the hook 

 of the unciform bone, where it is under cover of the pisi-uncinate 

 ligament. 



Relations — Superficial. — The integument, the expansion from the 

 flexor carpi ulnaris tendon to the front of the anterior annular 

 ligament, and the pisi-uncinate ligament. Deep. — ^The anterior 

 annular ligament. External. — ^The external vena comes, and hook 

 of the unciform bone. Internal. — ^The internal vena comes, ulnar 

 nerve, and pisiform bone. 



The branches of this part are unimportant. 



The third part of the ulnar artery will be described in connection 

 with the palm. 



Ulnar Venae Comites. — ^The ulnar artery in the first and second 

 parts of its course is accompanied by two venae comites, one being 

 placed on either side of the vessel, and the two communicate at 

 frequent intervals by transverse branches which lie upon it. They 

 commence in the venae comites of the inner parts of the superficial 

 and deep palmar arches, and they terminate above by uniting to 

 form the internal brachial vena comes. 



Ulnar Nerve. — ^The ulnar nerve enters the forearm by passing 

 through the interval between the internal epicondyle and olecranon 

 process, where it lies between the two heads of the flexor carpi 

 ulnaris. It then descends under cover of that muscle, lying upon 

 the flexor profundus digitorum. A little above the centre of the 

 forearm it meets with the ulnar artery, upon the inner side of 

 which it subsequently lies. On approaching the wrist it escapes 

 from beneath the flexor carpi ulnaris, and lies, with the artery, close 

 to the outer side of its tendon. It then passes over the anterior 

 annular ligament close to the outer side of the pisiform bone, 

 by which it is overhung, and subsequently on the inner side of 

 the hook of the unciform bone. Thereafter it enters the palm, 

 where it divides into its two terminal branches, superficial and 

 deep. 



Branches. — These are articular, muscular, and cutaneous. 



The articular branches, two or three in number, are given off to 

 the elbow-joint as the nerve passes between the internal epicondyle 

 and olecranon process. 



The muscular branches arise in the upper part of the forearm, 

 and are distributed to the flexor carpi ulnaris and the inner portion 

 of the flexor profundis digitorum. 



