596 



ANGIOLOGY 



In the Forearm 



and placed between the Flexor carpi ulnaris and Flexor digitorum sublimis. It is accompanied 

 by two vena? comitantes, and is overlapped in its middle third by the Flexor carpi ulnaris; the 

 ulnar nerve lies on the medial side of the lower two-thirds of the artery, and the palmar cutaneous 

 branch of the nerve descends on the lower part of the vessel to the palm of the hand. 



(6) At the wrist (Fig. 527) the ulnar artery is covered by the integument and the volar carpal 

 ligament, and lies upon the transverse carpal ligament. On its medial side is the pisiform bone, 

 and, somewhat behind the artery, the ulnar nerve. 



Peculiarities. The ulnar artery varies in its origin in the proportion of about one in thirteen 

 cases; it may arise about 5 to 7 cm. below the elbow, but more frequently higher, the brachia! 

 being more often the source of origin than the axillary. Variations in the position of this vessel 

 are more common than in the radial. When its origin is normal, the course of the vessel is rarely 

 changed. When it arises high up, it is almost invariably superficial to the Flexor muscles in the 

 forearm, lying commonly beneath the fascia, more rarely between the fascia and integument. 

 In a few cases, its position was subcutaneous in the upper part of the forearm, and subaponeurotic 

 in the lower part. 



Branches. The branches of the ulnar artery may be arranged in the following 

 groups : 



Anterior Recurrent. *..-, w / Volar Carpal. 



Posterior Recurrent. \ Dorsal Carpal. 



Common Interosseous. T ,, v j / Deep Volar. 

 T\/r in me Hand < ~ ^ . , TT , 



Muscular. \ Superficial Volar Arch. 



The anterior ulnar recurrent artery (a. recurrentes ulnaris anterior] arises imme- 

 diately below the elbow-joint, runs upward between the Brachialis and Pronator 

 teres, supplies twigs to those muscles, and, in front of the medial epicondyle, anasto- 

 moses with the superior and inferior ulnar collateral arteries. 



The posterior ulnar recurrent artery (a. recurrentes ulnaris posterior) is much 

 larger, and arises somewhat lower than the preceding. It passes backward and 

 medialward on the Flexor digitorum profundus, behind the Flexor digitorum sub- 

 limis, and ascends behind the medial epicondyle of the humerus. In the interval 

 between this process and the olecranon, it lies beneath the Flexor carpi ulnaris, 

 and ascending between the heads of that muscle, in relation with the ulnar nerve, 

 it supplies the neighboring muscles and the elbow-joint, and anastomoses with 

 the superior and inferior ulnar collateral and the interosseous recurrent arteries 

 (Fig. 529). 



The common interosseous artery (a. interossea communis) (Fig. 528), about 1 cm. 

 in length, arises immediately below the tuberosity of the radius, and, passing 

 backward to the upper border of the interosseous membrane, divides into two 

 branches, the volar and dorsal interosseous arteries. 



The Volar Interosseous Artery (a. interossea wlaris; anterior interosseous artery) 

 (Fig. 528), passes down the forearm on the volar surface of the interosseous mem- 

 brane. It is accompanied by the volar interosseous branch of the median nerve, 

 and overlapped by the contiguous margins of the Flexor digitorum profundus and 

 Flexor pollicis longus, giving off in this situation muscular branches, and the nutrient 

 arteries of the radius and ulna. At the upper border of the Pronator quadratus it 

 pierces the interosseous membrane and reaches the back of the forearm, where it 

 anastomoses with the dorsal interosseous artery (Fig. 529). It then descends, in 

 company with the terminal portion of the dorsal interosseous nerve, to the back 

 of the wrist to join the dorsal carpal net-work. The volar interosseous artery gives 

 off a slender branch, the arteria mediana, which accompanies the median nerve, and 

 gives offsets to its substance; this artery is sometimes much enlarged, and runs 

 with the nerve into the palm of the hand. Before it pierces the interosseous 

 membrane the volar interosseous sends a branch downward behind the Pronator 

 quadratus to join the volar carpal network. 



The Dorsal Interosseous Artery (a. interossea dorsalis; posterior interosseous artery] 

 (Fig. 529) passes backward between the oblique cord and the upper border of the 

 interosseous membrane. It appears between the contiguous borders of the Supinator 





