FOREARM AND HAND 105 



Arteria Ulnaris (Ulnar Artery). This is the larger of the 

 two terminal branches of the brachial trunk. It takes origin 

 in the fossa cubitalis at the level of the neck of the radius. In 

 the proximal third of the forearm it inclines obliquely distally 

 and medially, and then it proceeds distally and vertically to the 

 wrist. It enters the palm by passing anterior to the transverse 

 carpal ligament. In the proximal oblique portion of its course 

 the vessel is deeply placed, and is crossed by both heads of the 

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

 and the flexor digitorum sublimis. In its distal vertical part it 

 is overlapped on the medial side by the flexor carpi ulnaris, 

 but a short distance above the wrist it becomes superficial, 

 and lies in the interval between the tendon of the flexor 

 carpi ulnaris on the medial side and the tendons of the 

 flexor sublimis on the lateral side. On the transverse carpal 

 ligament it is placed close to the lateral side of the pisiform 

 bone, and is covered by a strong band of fascia, the volar 

 carpal ligament (pp. 101, 121), which lies in front of the 

 transverse ligament. Throughout its entire course it -is 

 accompanied by two vena comites. It has important rela- 

 tionships with the median and ulnar nerves. The median 

 nerve, which lies upon its medial side at its origin, soon 

 crosses it, but as it does so it is separated from the artery by 

 the deep head of the pronator teres. The ulnar nerve in the 

 proximal third of the forearm is separated from the vessel 

 by a wide interval, but in the distal two-thirds of the forearm 

 it closely accompanies the artery, and lies on its medial side. 



In the fossa cubitalis the ulnar artery rests upon the 

 brachialis ; beyond this it is in contact behind with the flexor 

 digitorum profundus ; whilst at the wrist the artery lies upon 

 the anterior surface of the transverse carpal ligament. 



Branches of the Ulnar Artery. In the forearm the ulnar 

 artery gives off the following branches : 



1. A. recurrens ulnaris volaris. 



2. A. recurrens ulnaris dorsalis. 



3. A. interossea communis. 



4. A. carpea volaris. 



5. A. carpea dorsalis. 



6. Kami musculares. 



The rami musculares are of small size, and come off at 

 variable points for the supply of the neighbouring muscles. 



The a. recurrens ulnaris volaris (O.T. anterior ulnar re- 

 current) is the smaller of the two recurrent branches. It runs 

 proximally, anterior to the medial epicondyle of the humerus, 

 in the interval between the pronator teres and the brachialis 



