492 ARTERIES. 



the elbow, and in all the other cases much higher, the brachial being a more frequent source of 

 origin than the axillary. 



Variations in the position of this vessel are more frequent 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 in- 

 variably 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, subaponeurotic in the lower part. 



Surgical Anatomy. The application of a ligature to this vessel is required in cases of wound 

 of the artery, or of its branches, or in consequence of aneurism. In the upper half of the fore- 

 arm, the artery is deeply seated beneath the superficial flexor muscles, and their division would 

 be requisite in a case of recent wound of the artery in this situation, in order to secure it, but 

 under no other circumstances. In the middle and lower third of the forearm, this vessel may be 

 easily secured by making an incision on the radial side of the tendon of the Flexor Carpi Ulna- 

 ris ; the deep fascia being divided, and the Flexor Carpi TJlnaris and its companion muscle, the 

 Flexor Sublimis, being separated from each other, the vessel will be exposed, accompanied by its 

 vena? comites, the ulnar nerve lying on its inner side. The veins being separated from the artery, 

 the ligature should be passed from the ulnar to the radial side, taking care to avoid the ulnar nerve. 



The branches of the ulnar artery may be arranged into-the following groups : 



f Anterior ulnar recurrent. 

 I Posterior ulnar recurrent. 



Forearm. -{ T , ( Anterior interosseous. 



Interosseous. < r> , 



( Posterior interosseous. 



[ Muscular. 



Wrist \ Anterior carpal. 

 ( Posterior carpal. 



Hand \ Deep or communicating branch. 

 ' { Digital. 



The anterior ulnar recurrent (Fig. 287) arises immediately below the elbow- 

 joint, passes upwards and inwards between the Brachialis Anticus and Pronator 

 Eadii Teres, supplies those muscles, and, in front of the inner condyle, anasto- 

 moses with the anastomotica magna and inferior profunda. 



The posterior ulnar recurrent is much larger, and arises somewhat lower than 

 the preceding. It passes backwards and inwards, beneath the Flexor Sublimis, 

 and ascends behind the inner condyle of the humerus. In the interval between 

 this process and the olecranon, it lies beneath the Flexor Carpi Ulnaris, ascend- 

 ing between the heads of that muscle, beneath the ulnar nerve ; it supplies the 

 neighboring muscles and joint, and anastomoses with the inferior profunda, 

 anastomotica magna, and interosseous recurrent arteries (Fig. 288). 



The interosseous artery (Fig. 287) is a short trunk, about an inch in length, and 

 of considerable size, which arises immediately below the tuberosity of the 

 radius, and, passing backwards to the upper border of the interosseous mem- 

 brane, divides into two branches, the anterior and posterior interosseous. 



The anterior interosseo'us passes down the forearm on the anterior surface of 

 the interosseous membrane, to which it is connected by a thin aponeurotic arch. 

 It is accompanied by the interosseous branch of the median nerve, and over- 

 lapped by the contiguous margins of the Flexor Profundus Digitorum and 

 Flexor Longus Pollicis muscles, giving off in this situation muscular branches, 

 and the nutrient arteries of the radius and ulna. At the upper border of the 

 Pronator Quadratus, a brancli descends in front of that muscle, to anastomose 

 in front of the carpus 'with branches from the anterior carpal and deep palmar 

 arch. The continuation of the artery passes behind the Pronator Quadratus 

 (Fig. 288), and, piercing the interosseous membrane, descends to the back of the 

 wrist, where it anastomoses with the posterior interosseous and the posterior 

 carpal branches of the radial and ulnar arteries. The anterior interosseous 

 gives off a long, slender branch, which accompanies the median nerve, and 

 gives offsets to its substance. This, the median artery, is sometimes much en- 

 larged. 



The posterior interosseous artery passes backwards through the interval between 

 the oblique ligament and the upper border of the interosseous membrane, and 



