BRANCHES OP THE RADIAL. 



413 



Fig. 220. Ulnar and Radial Arteries. 

 Deep View. 



The princeps pollicis arises from the radial just as it turns inwards to the deep 

 part ol'jthe hand ; it descends between the Abductor indicis and Adductor pollicis, 

 along the ulnar side of the meta- 

 carpal bone of the thumb, to the 

 base of the first phalanx, where it 

 divides into two branches, which 

 run along the sides of the palmar 

 aspect of the thumb, and form an 

 arch on the under surface of the 

 last phalanx, from which branches 

 are distributed to the integument 

 and cellular membrane of the thumb. 



The radialis indicis arises close 

 to the preceding, descends between 

 the Abductor indicis and Adductor 

 pollicis, and runs along the radial 

 side of the index-finger to its ex- 

 tremity, where it anastomoses with 

 the collateral digital artery from the 

 superficial palmar arch. At the 

 lower border of the Adductor 

 pollicis this vessel anastomoses with 

 the princeps pollicis, and gives a 

 communicating branch to the super- 

 ficial palmar arch. 



The perforantes, three in number, 

 pass backwards between the heads 

 of the last three Dorsal interossei 

 muscles, to inosculate with the dor : 

 sal interosseous arteries. 



The palmar inter ossese, three or 

 four in number, are branches of the 

 deep palmar arch ; they run for- 

 wards upon the Interossei muscles, 

 and anastomose at the clefts of the 

 fingers with the digital branches of 

 the superficial arch. 



ULXAR ARTERY. 



trumA of Ulnar 



The Ulnar Artery, the larger of 

 the two subdivisions of the bra- 

 chial, commences a little below the 

 bend of the elbow, and crosses the 

 inner side of the forearm obliquely 

 to the commencement of its lower 

 half; it then runs along its ulnar 

 border to the wrist, crosses the annu- 

 lar ligament on the radial side of the 



pisiform bone and passes across the palm of the hand, forming the superficial 

 palmar arch, which terminates by inosculating with the superficialis vola3. 



Relations in the Forearm. In its upper half, it is deeply seated, being covered 

 by all the superficial Flexor muscles, excepting the Flexor carpi ulnaris ; crossed 

 by the median nerve, which, for about an inch lies to its inner side ; and it lies 

 upon the Brachialis anticus and Flexor profundus digitorum muscles. In the 

 tower half of the forearm, it lies upon the Flexor profundus, being covered by the 

 integument, and the superficial and deep fasciae, and is placed between the Flexor 



