278 The Ulnar Artery 



the tendon of the flexor carpi radialis, it is seen to cross that of the 

 artery. 



As the muscles narrow into their tendons the artery is found 

 nearer to the surface, between the flexor carpi ulnaris and the inner- 

 most tendon of the flexor sublimis digitorum, being then covered only 

 by the skin and the superficial and deep fascine, a branch or two of 

 the anterior ulnar vein and of the internal cutaneous nerve. 



The ulnar artery rests upon, first, the brachialis anticus, and, in the 

 rest of its course, on the flexor profundus digitorum, a muscle which 

 is bulky enough to prevent the artery coming into relationship with 

 either the ulna or the square pronator. 



The first definite external relationship is the innermost tendon of 

 the flexor sublimis. 



On the inner side of the artery are the ulnar nerve and the flexor 

 carpi ulnaris, but these structures are not approached until the vessel 

 has completed its inward bend, that is, not until it has reached nearly 

 halfway to the wrist. The artery is accompanied by a small vein on 

 either side. 



Branches. The anterior ulnar recurrent ascends deeply in the 

 groove between the pronator teres and the brachialis anticus, to com- 

 municate with the anastomotica magna and the inferior profunda. 



The posterior ulnar recurrent ascends behind the internal con- 

 dyle, and communicates with the posterior branches of the anasto- 

 motica magna, and with the inferior and superior profundas. It passes 

 between the origins of the flexors sublimis and profundus, and between 

 the heads of the flexor carpi ulnaris, lying against the ulnar nerve. 



The common Interosseous speedily divides into the anterior 

 and posterior interosseous, the former of which descends upon the 

 interosseous membrane in the crevice between the flexor profundus 

 digitorum and the flexor longus pollicis. But, having reached the 

 pronator quadratus, it passes through the membrane to the back of 

 the fore-arm, where it anastomoses with the posterior interosseous 

 and the posterior carpal arteries. It gives off muscular twigs, and 

 the nutrient branches to the radius and ulna, the comes ncri'i mcdiani, 

 and branches to anastomose with the anterior carpal arch. The 

 branches to the radius and ulna run towards the elbow. 



The posterior interosseous runs backwards between the oblique 

 ligament and the interosseous membrane, and then between the 

 adjacent borders of the supinator brevis and the extensor ossis. It 

 afterwards descends between the superficial and deep layer of muscles, 

 and ends in anastomosis with the anterior interosseous and the pos- 

 terior carpal arch. It gives off the interosseous recurrent branch, 

 which ascends between the external condyle and the olecranon process, 

 and beneath the anconeus, to anastomose with the superior profunda, 

 and perhaps with the posterior ulnar recurrent or the anastomotica 

 magna. 



