



[R ARTERY 



The first dorsal metacarpal arises just before the radial artery passes between 

 the two heads of the first Interosseous dorsalis and divides almost immediately 

 into two branches which supply the adjacent sides of the thumb and index finger ; 

 the radial side of the thumb receives a branch directly from the radial artery. 



The arteria princeps pollicis arises from the radial just as it turns medialward 

 to the deep part of the hand ; it descends between the first Interosseous dorsalis and 

 Adductor pollicis obliquus, along the ulnar side of the metacarpal bone of the 

 thumb to the base of the first phalanx, where it lies beneath the tendon of the 

 Flexor pollicis longus and divides into two branches. These make their appear- 

 ance between the medial and lateral insertions of the Adductor pollicis obliquus, 

 and run along the sides of the thumb, forming on the volar surface of the last 

 phalanx an arch, from which branches are distributed to the integument and 

 subcutaneous tissue of the thumb. 



The arteria volaris indicis radialis (radialis indicis artery] arises close to the pre- 

 ceding, descends between the first Interosseus dorsalis and Adductor pollicis trans- 

 versus, and runs along the radial side of the index finger to its extremity, where it 

 anastomoses with the proper digital artery, supplying the ulnar side of the finger. At 

 the lower border of the Adductor pollicis transversus this vessel anastomoses with 

 the princeps pollicis, and gives a communicating branch to the superficial volar arch. 

 The a. princeps pollicis and a. volaris indicis radialis may spring from a common 

 trunk termed the first volar metacarpal artery. 



The deep volar arch (arcus volaris profundus; deep palmar arch) (Fig. 528) is 

 formed by the anastomosis of the terminal part of the radial artery with the deep 

 volar branch of the ulnar. It lies upon the carpal extremities of the metacarpal 

 bones and on the Interossei, being covered by the Adductor pollicis obliquus, the 

 Flexor tendons of the fingers, and the Lumbricales. Alongside of it, but running 

 in the opposite direction that is to say, toward the radial side of the hand is 

 the deep branch of the ulnar nerve. 



The volar metacarpal arteries (aa. metacarpeoe volares; palmar interosseoiis 

 arteries), three or four in number, arise from the convexity of the deep volar arch; 

 they run distally upon the Interossei, and anastomose at the clefts of the fingers 

 with the common digital branches of the superficial volar arch. 



The perforating branches (rami perforantes) , three in number, pass backward 

 from the deep volar arch, through the second, third, and fourth interosseous spaces 

 and between the heads of the corresponding Interossei dorsalis, to anastomose 

 with the dorsal metacarpal arteries. 



The recurrent branches arise from the concavity of the deep volar arch. They 

 ascend in front of the wrist, supply the intercarpal articulations, and end in the 

 volar carpal network. 



The Ulnar Artery (A. Ulnaris) (Fig. 528). 



The ulnar artery, the larger of the two terminal branches of the brachial, begins 

 a little below the bend of the elbow, and, passing obliquely downward, reaches 

 the ulnar side of the forearm at a point about midway between the elbow and the 

 wrist. It then runs along the ulnar border to the wrist, crosses the transverse 

 carpal ligament on the radial side of the pisiform bone, and immediately beyond 

 this bone divides into two branches, which enter into the formation of the superficial 

 and deep volar arches. 



Relations. (a) In the forearm. In its upper half, it is deeply seated, being covered by the 

 Pronator teres, Flexor carpi radialis, Palmaris longus, and Flexor digit orum sublimis; it lies 

 upon the Brachialis and Flexor digitorum profundus. The median nerve is in relation with the 

 medial side of the artery for about 2.5 cm. and then crosses the vessel, being separated from it 

 by the ulnar head of the Pronator teres. In the lower half of the forearm it lies upon the Flexor 

 digitorum profundus, being covered by the integument and the superficial and deep fasciae, 



