310 A MANUAL OF ANATOMY, 



Nerve Supply. From the ulnar, by its deep palmar 

 branch. The filaments arising from the eighth cervical 

 nerve. 



Action. See Dorsal interossei. 



The Deep Palmar Arch. Diag. 1 8. Fig. 67. 



After the radial artery has gained the front of the hand 

 by coming through between the first and second metacar- 

 pal bones, it turns inward between the adductor and inner 

 head of the flexor brevis pollicis, and crosses the bases of 

 the second, third, and fourth metacarpal bones and inter- 

 ossei muscles, to form the deep arch by anastomosing with 

 the deep communicating artery from the ulnar. 



The line indicating the deep arch is half an inch nearer 

 the wrist-joint than the superficial. 



Branches of the Deep Arch. (Radial in the hand.) 



(a) Princeps pollicis, is a branch from the radial just 

 as it enters the palm. It passes outward and downward 

 between the adductor pollicis and the abductor indicis 

 muscles. Over the metacarpophalangeal joint it divides 

 into two branches, one for each side of the thumb, (b) 

 Radialis indicis, issues between the adductor pollicis and 

 abductor indicis muscles, descends along the outer anterior 

 border of the index finger to its tip. (c) Palmar interos- 

 seous arteries, three in number ; descend between the in- 

 dex and middle, middle and ring, and ring and little fingers, 

 along the anterior surface of the interossei muscles, and 

 terminate by joining the digital branches from the super- 

 ficial arch. See page 305. They supply the adjoining 

 muscles, (d) The recurrent, are two or more small twigs 

 which pass upward to the front of the carpus and form an 

 anastomosis with the anterior carpal branches of the radial, 

 ulnar, and anterior interosseous arteries, (e) The perforat- 



