RADIAL ARTERY. 63 



pn >(...-< >f the radius. This vessel is smaller than the ulnar artery, 

 though it appears in direction to be the continuation of the brachial 

 trunk. It is partly deep and partly superficial ; and where it is 

 superficial, it can be felt beating as the pulse near the wrist during life. 



In its uj'pfi- half the vessel is placed under cover of the supinator Relations to 

 longus ( 8 ) ; and it rests successively on the following muscles : the Cupper' 

 tendon of the biceps ( 9 ), the fleshy supinator brevis, the pronator half > 

 teres ( 3 ), and part of the thin, radial origin of the flexor sublimis ( 6 ). 



In its lower half the artery is superficial, being covered only by in lower 

 the integuments and the deep fascia. Here it is placed in a hollow half ' 

 between the tendons of the supinator longus ( 8 ) and flexor carpi 

 radialis ( 4 ), and it lies, in this part, from above down on the origin 

 of the flexor sublimis, on two muscles of the deep group, viz., flexor 

 longus pollicis and pronator ^uadratus, and lastly on the end of 

 the radius. 



J'eins. Venae comites lie on the sides, with cross branches over to veins; 

 the artery. 



Xerve. The radial nerve is on the outer side of the artery in the to nerve, 

 upper two-thirds of the forearm, but is separated from the vessels 

 by a slight interval near the elbow. In the lower third the nerve 

 passes backwards and becomes superficial behind the tendon of the 

 supinator longus. 



Branches. The radial artery in this part of its course furnishes Branches : 

 many unnamed muscular and cutaneous offsets, and three named 

 branches, viz., recurrent radial, superficial volar, and anterior carpal. 



a. The radial recurrent (fig. 24) is the first branch, and supplies radial re- 

 the muscles on the outer side of the limb. Its course is almost current 

 transverse to the supinator longus, beneath which it terminates in 

 that muscle and the two radial extensors of the wrist. One offset 

 ascends beneath the supinator, and anastomoses with the superior 

 profunda branch of the brachial artery. 



6. The superficial volar branch (fig. 27, c, p. 72) is very variable superficial 

 in size, and arises near the lower end of the radius. It is directed vc 

 towards the palm of the hand, across or through the mass of 

 muscles in the ball of the thumb ; and it either ends in those 

 muscles, or joins the superficial palmar arch. 



c. The anterior carpal branch is very small, and will be seen in anterior 

 the examination of the deep muscles. Arising rather above the car P al - 

 end of the radius, it passes transversely inwards at the lower border 

 of the pronator quadratus, and anastomoses with a similar branch 

 from the ulnar artery. From the arch thus formed offsets are given 

 to the carpus. 



Peculiarities of the radial artery. Sometimes the radial arises high in the Variations 

 arm, and its course then is close to the brachial artery, along the edge of the of the 

 biceps muscle ; and in passing the bend of the elbow it is occasionally sub- 

 cutaneous, i.e. , above the deep fascia, and liable to injury in venesection. In 

 the forearm the artery may likewise be subcutaneous, and superficial to the 

 supinator longus muscle. 



Dissection. To bring into view the flexor sublimis digitorum, Dissection 

 the flexor carpi radialis and palinaris longus must be cut through 



