584 



THE BLOOD-VASCULAR SYSTEM 



(musculo-spiral) nerve, and anastomoses with the profunda artery. A third descends with the 

 superficial radial nerve under cover of the brachio-radialis, supplying that muscle. The 

 radial recurrent also gives off branches to the elbow-joint. 



(2) The muscular branches [rami musculares) come off irregularly to supply the contiguous 

 muscles on the lateral side of the forearm 



(3) The volar radial carpal branch [ramus carpeus volaris] arises from the medial side of the 

 radial artery about the level of the lower border of the pronator quadratus. It crosses the front 

 of the radius beneath the flexor muscles, and anastomoses with the volar carpal branch of the 

 ulnar, forming the volar carpal rete. This plexus is joined above by terminal twigs from the 

 volar interosseous artery, and below by recurrent branches from the deep volar arch. It sup- 

 plies branches to the lower end of the radius, and to the wrist and carpal joints. 



(4) The superficial volar branch [ramus volaris superficialis] leaves the radial artery as the lat- 

 ter vessel is about to turn over the radial collateral ligament to the back of the wrist. It courses 

 forward over the short muscles of the ball of the thumb, and anastomoses with the superficial. 



Fig. 475. — The Bend of the Elbow, Left Side. 

 (From a dissection by Dr. Alder Smith in the Museum of St. Bartholomew's Hospital. 



Median nerve 

 Posterior branch of in- 

 ferior ulnar collateral 



Branches of medial f 



anti-brachial -i 

 cutaneous nerve [ 



Basilic vein 



Brachialis 

 Volar branch of inferior 

 ulnar collateral 

 Median antibrachial vein 



Median cubital vein 



Muscular branch of 

 median nerve 



Tendon of biceps 

 Lacertus fibrosus 



Brachialis 



Deep median vein 

 Ulnar artery 



Pronator teres 



Radial artery 



Biceps 



Vena comitans of 

 brachial artery 

 Basilic vein 



Brachialis 



Cephalic vein 

 Brachial artery 

 Dorsal anti- 

 brachial cuta- 

 neous nerve 

 Radial n. and as- 

 cending branch 

 of radial recur- 

 rent artery 

 'Accessory ceph- 

 alic vein 

 Cephalic vein 

 Ascending br. of 

 radial recurrent 

 Deep radial 



nerve 



Radial recurrent 



artery 



Brachio-radialis 



Descending br. of 

 radial recurrent 



Cephalic vein 



Superficial 

 radial 

 nerve 



branch of the ulnar artery to complete the .superficial volar arch. It supplies small branches 

 to the muscles of the ball of the thumb, and frequently terminates in these muscles without 

 joining the arch. Occasionally it passes beneath the abductor poUicis brevis. 



II. The Radial Artery at the Wrist 



The radial artery at the wrist winds over the radial side of the carpus, under 

 the extensor tendons of the thumb, from a spot a little below and medial to the 

 styloid process of the radius to the base of the first interosseous space, where it 

 sinks between the two heads of the first dorsal interosseous muscle into the palm, 

 to form, by anastomosing? with the deep branch of the ulnar artery, the deep volar 

 arch. A line drawn from 1.2 cm. (i in.) medial to the styloid process to the 

 base of the first interosseous space, whi(!h can be distinctly felt on the back of 

 the hand, will roughly indicate the course of the artery (fig. 476). 



