418 



ARTERIES OF THE UFPER LIMB. 



enlai'ged. it furnishes one or two digital branches, and along with this the anas- 

 tomosis with the superficial arch may be absent. The superficial volar branch 

 occasionally arises as much as an inch and a half higher than usual. 



The Jiivt domal iiifc/v-s.'icou.s branch (metacarpal), which descends on the second 

 infei'osATflus space to the cleft between the index and middle fingers, is not 

 unfrequently so large as to furnish the collateral digital branch to each of those 

 fingers. 



The carpal and intcroxwom (metacarpal) branches of the radial are sometimes 

 small, their place being supplied by the perforating offset of the anterior 

 interosseous, apparently by an enlargement of' the ordinary anastomosis between 

 them. 



The radial artery very fi-equently gives of: a communicating branch to the 

 superficial arch, near the lower border of the adductor pollicis. 



Fig 273. Fig. 273. — ^Dissectiom op the Left Arm, show- 



ing AN ENLARfiED IMeDIAN ArTERT WHICH RE- 

 PLACES THE Radial akd Ulnar Arteries in 

 THE supply of Palmar Digital Arteries to 

 HALF THE FiNGERS (from Tiedemann). \ 



1, lower pai-t of the bracliial arteiy ; 2, radial 

 artery, not giving any superficial volar branch ; 3, 

 recurrent radial branch ; 4, idnar artery passing; 

 superficially over the wrist and supplying at 4', 

 digital arteries to half the hand ; 5, tlie enlarged 

 median artery passing in front of the annular liga- 

 ment of the carpus, and supplying 5', digital vessels 

 to the outer half of the liand. 



DEEP PALMAR ARCH. 



The deep palmar arch, the continuation 

 of the radial artery, commences at the 

 upper end of the first interosseous space 

 between the heads of the abductor indicis, 

 turns transA'ersely across the pahn towards 

 the fourth metacarpal l^one, and inoscu- 

 lates with the communicating branch of 

 the ulnar artery. The convexity of the 

 arch thus formed is directed downwards. 

 It rests on the interosseous muscles and 

 on the metacarpal bones immediately 

 below their carpal extremities, and is 

 covered by the flexor brevis pollicis, the 

 flexor tendons of the fingers, and the mus- 

 cles of the little finger. It is nearer to the 

 carpus than the superficial arch, and differs 

 from it in retaining its size almost un- 

 diminished. It is in part accompanied by 

 the deep branch of the ulnar nerve, which 

 runs from the inner end of the arch out- 

 wards. 



Branches. — (<^/) The recurrent branches (rami 



retrogradi. — Haller), from the upper concave 



side, ascend and anastomose with the branches 



from the anterior carpal arch. 



(h) The superior 2)erf orating \ix^uckQB,th.veQ in number, pass backwards through 



the upper extremities of the last three interosseous spaces to iiiosculate with the 



dorsal interosseous ai-teries. 



