THE VASCULAR SYSTEM. 139 



structures in the subscapular fossa, winds around the neck 

 of the humerus to its distribution in the triceps and deltoid 

 muscles. 



The brachial artery, in addition to several muscular 

 branches, gives origin to the anterior circumflex, superior 

 profunda, the nutrient, and anastomotica magna. The an- 

 terior circumflex supplies the biceps and head of the hu- 

 merus. The superior profunda is distributed to the muscles 

 on the caudal aspect of the humerus. The nutrient artery 

 enters the nutrient foramen of the humerus. The anasto- 

 motica magna is the small branch supplying the convexity 

 of the elbow. The brachial artery after passing through 

 the supracondyloid foramen takes the name of radial. 



The radial artery, which lies deep beneath the flexor 

 muscles on the caudal aspect of the proximal half of the 

 radius (Fig. 74), becomes superficial along its distal half, 

 where the vessel is covered by skin and fascia only. In the 

 region of the wrist, it curves dorsad and then pierces be- 

 tween the second and third metacarpals to the palmar side, 

 where it sends branches to each of the digits, and forms 

 the palmar arch by anastomosing with the ulnar artery be- 

 neath the flexor muscles. In addition to a few small 

 branches, the radial gives off the following: the radial re- 

 currens, supplying the concavity of the elbow; the ulnar 

 recurrens, supplying the convexity of the elbow; the poste- 

 rior inter osseous, passing caudad between the radius and 

 the ulna to the extensor muscles; the anterior interosseous, 

 passing along the cranial side of the interosseous mem- 

 brane; the ulnar, extending beneath the flexor muscles, 

 which it supplies, to the palm, where it anastomoses with 

 the radial to form the palmar arch; and the volar branch, 

 supplying the superficial palmar region. The ul-nar and 

 anterior interosseous frequently arise from the same trunk, 

 as shown in the figure. The ulnar artery in the cat is so 



