ULNAR ARTERY. 275 



the artery. Before it turns under the tendons of the extensors 

 of the thumb, it sends a branch over the wrist called dorsaHs 

 carpi radialis towards the root of the thumb, from which pro- 

 ceeds a branch to anastomose with the volar branch of the 

 ulnar ; and another, not so large, named anterior carpi radialis 

 which is frequently continued on the radial or external side of 

 the thumb, very near to its extremity. While the radial artery 

 is under the aforesaid tendons, it sends off small branches to 

 the back of the wrist and back of the hand, metacarpal 

 branches, and two to the back of the thumb called dorsaks 

 pollicis. Those which are distributed to the wrist and back of 

 the hand, generally anastomose with the small branches of the 

 ulnar and interosseal arteries. 



The three branches into which the radial artery divides be- 

 tween the metacarpal bones of the thumb and index are, 1st, a 

 branch to the external sides of the index fingers (^radialis indicis) ; 

 2dly, a branch to the thumb, that sometimes divides into two, 

 which pass up on the anterior or volar surface, aud sometimes 

 continue, without much diminution, on the internal side of the 

 thumb, near to the end of the last phalanx ; this is called the 

 superficialis voice, and seems from its direction, though not 

 from its size, to be the proper continuation of the radial artery. 

 Occasionally, however, it is met with of such large size, that 

 when cut it gives rise to troublesome hemorrhage ; and, 3dly, a 

 branch called Palmaris Profunda, which dips down into the 

 palm of the hand, and proceeding in contact with the metacar- 

 pal bone, under the flexor tendons, &c., forms an arch which 

 extends across the hand, and often terminates by anastomoses 

 with another but more superficial arch, soon to be described, 

 which is formed by the ulnar artery. 



This flexure, which is denominated Arcus Profundus, sends 

 off branches of a very small size, which are distributed to the 

 bones, ligaments, muscles, &c., contiguous to it. 



The Common Trunk of the Ulnar and Interosseal Arteries 

 Passes under several of the muscles which originate from 



