BRANCHES OF THE ULNAR ARTERY. 543 



is to be sought for, and the fascia incised in this line. The Flexor carpi ulnaris is now to be 

 carefully separated from the other muscles, when the ulnar nerve will be exposed, and must be 

 drawn aside. Some little distance below the nerve the artery will be found accompanied by its 

 venae comites, and may be ligatured by passing the needle from within outward. 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 ulnaris : the deep fascia being divided, and the 

 Flexor carpi ulnaris and its companion muscle, the Flexor sublimis, being separated from each 

 other, the vessel will be exposed, accompanied by its venae 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 in the following groups : 



T Anterior Ulnar Recurrent. 

 Posterior Ulnar Recurrent. 



Forearm. < > ( Anterior Interosseous. 



i Interosseous T . . . 



( Posterior Interosseous. 



(^ Muscular. 

 nr . f Anterior Carpal. 



1 Posterior Carpal. 

 rr 7 f Deep Palmar or Communicating. 



\ Superficial Palmar Arch. 



The anterior ulnar recurrent (Fig. 305) arises immediately below the elbow-joint, 

 passes upward and inward between the Brachialis anticus and Pronator radii teres, 

 supplies twigs to those muscles, and, in front of the inner condyle, anastomoses 

 with the anastornotica magna and inferior profunda. 



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

 the preceding. It passes backward and inward, 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, and ascending 

 between the heads of that muscle, in relation with the ulnar nerve ; it supplies the 

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

 tomotica magna, and interosseous recurrent arteries (Fig. 306). 



The interosseous artery (Fig. 305) is a short trunk about half an inch in length, 

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

 radius, and, passing backward to the upper border of the interosseous membrane, 

 divides into two branches, the anterior and posterior interosseous. 



The anterior interosseous 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 overlapped 

 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 branch descends beneath the muscle to anastomose in front of the carpus with 

 the anterior carpal arch. The continuation of the artery passes behind the Pro- 

 'nator quadratus, and, piercing the interosseous membrane, reaches the back of 

 the forearm, and anastomoses with the posterior interosseous artery (Fig. 306). 

 It then descends to the back of the wrist to join the posterior carpal arch. The 

 anterior interosseous gives off a long, slender branch, the median artery, which 

 accompanies the median nerve and gives offsets to its substance. This artery 

 is sometimes much enlarged, and accompanies the nerve into the palm of the 

 hand. 



The posterior interosseous artery passes backward through the interval between 

 the oblique ligament and the upper border of the interosseous membrane. It 

 appears between the contiguous borders of the Supinator brevis and the Extensor 

 ossis metacarpi pollicis, and runs down the back part of the forearm, between the 

 superficial and deep layer of muscles, to both of which it distributes branches. 

 At the lower part of the forearm it anastomoses with the termination of the anterior 

 interosseous artery. Then, continuing its course over the head of the ulna, it 



