THE ULXAR AETERY. 407 



ULNAR ARTERY. 



The ulnar artery, the larger of the two vessels into "which the brachial 

 •divides, extends along the inner side of the fore-arm into the palm of 

 the hand, where, joining a branch of the radial, opposite the muscles of 

 the thumb, it forms the superficial palmar arch. In this course it 

 inclines at first downwards and inwards, describing a slight curve, the 

 convexity of which is directed inwards, and passes under cover of the 

 superficial muscles arising frona the inner condyle of the humerus, viz., 

 the pronator teres, flexor carpi radialis, palmaris longus, and flexor 

 sublimis, until it reaches the flexor carpi ulnaris near the junction of 

 the upper with the middle third of the fore-arm ; at this point the 

 artery comes into contact with the ulnar nerve, which was previously 

 separated from it by a considerable interval, and changing its direction, 

 descends vertically ^Yith the nerve towards the inner border of the 

 palm of the hand. Descending along the radial border of the tendon 

 of the flexor ulnaris muscle, the ulnar artery reaches the outer or radial 

 side of the pisiform bone, where, still accompanied by the nerve, it 

 passes over the cutaneous surface of the anterior annular ligament of 

 the wrist into the ])alm of the hand. Its disposition in the hand will 

 be separately described. 



In the first half of its course through the fore-arm, the artery is 

 deep seated, being covered by the muscles arising from the inner condyle 

 ■of the humerus which have been already enumerated. About the 

 middle of the fore-arm it is overlapped by the fleshy part of the flexor 

 carpi ulnaris ; but below that, it becomes more superficial, being over- 

 laid by the tendon of the muscle, and covered by the skin, the fascia of 

 the fore-arm, and a thin layer of membrane by which the vessel is 

 •bound down to the muscle beneath. At first the ulnar artery lies on 

 the insertion of the brachialis anticus into the coronoid process of the 

 oilna ; then on the flexor profundus in the rest of the fore-arm, and 

 lastly, on the annular ligament of the carpus. Below the point at 

 which it emerges from under the flexor carpi ulnaris (or a little below 

 the middle of "the fore-arm), the tendon of that muscle is on its inner 

 or ulnar side. 



Relation to Nerves. — The median nerve lies immediately on the inner 

 side of the ulnar artery at its origin, but being directed down the middle 

 of the fore-arm it soon passes over the vessel, separated from it at the 

 point of crossing by the deep head of the pronator teres muscle. _ As 

 the ulnar nerve descends behind the inner condyle of the humerus, it is 

 removed from the ulnar artery by a considerable interval at the upper 

 l)art of the fore-arm ; but as the vessel inclines inwards, it approaches 

 the nerve, and is accompanied by it in the lower half of its course — the 

 nerve lying close to its inner side. A small branch of the ulnar nerve 

 descends upon the lower part of the vessel. 



Relation to F(?«?s.— Two veins (vente comites) accompany the ulnar 

 artery, and are frequently united by branches crossing it. 



Branches. — The ulnar artery gives off in the fore-arm the anterior 

 and posterior recurrent, the interosseous, and several muscular 

 branches. At the wrist it gives off the anterior and posterior carpal 

 branches. 



The anterior ulnar recurrent artery, a small branch, arches inwards 

 and upwards from the upper part of the ulnar artery, in front of the 

 inner condyle, running on the brachialis anticus muscle, and covered by 



