UPPER EXTREMITY AND THORAX, POSTERIOR. 387 



The arteries which form the anastomosis about the 

 elbow-joint are the following- : In front of the elbow : 

 On the outer side there is the termination of the superior 

 profunda above and the recurrent radial below ; on the 

 inner side the anterior branch of the anastomotica magna 

 above and the anterior ulnar recurrent below. 



Behind the elbow : On the outer side the articular branch 

 of the superior profunda above, and the recurrent interos- 

 seous below ; on the inner side the posterior branch of the 

 anastomotica magna and the inferior profunda above, with 

 the posterior ulnar recurrent below. 



On the back of the elbow all these arteries inosculate to 

 form a free plexus and communication with each other. 



The Radial Artery at the Wrist. Fig. 79. 



Continuing the description of the artery from the lower 

 end of the radius where it was left off, see page 293. 



The artery is seen to run backward around the lower end 

 of the radius, between the tendons of the extensor ossis 

 metacarpi and brevis pollicis and the external lateral liga- 

 ment of the wrist-joint, to the interval between the bases of 

 the first and second metacarpal bones, where it lies under the 

 tendon of the extensor longus pollicis muscle. It now 

 passes forward and inward between the first and second 

 metacarpal bones and the two heads of the abductor indicis 

 muscle to the palmar side of the hand, where it is continued 

 as the deep arch. See page 310. 



The Branches of the Radial at the Back of the Wrist. 

 (i) The posterior carpal arises as the radial issues from 

 under the tendon of the extensor brevis pollicis, runs 

 inward across the back of the wrist, and terminates by anas- 

 tomosing with the posterior ulnar carpal and the anterior 

 and posterior interosseous arteries. From this posterior 



