400 



RADIAL AETEEY. 



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 transversely across [the palm towards the fourth 

 metacarpal bone, and inosculates 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 muscles of the little finger. It is 



nearer to the carpus than the superficial 



Fi S- 28 - arch, and differs from it in retaining its 



size almost undiminished. It is in part 

 accompanied by the deep branch of the ulnar 

 nerve, which runs from the inner end of 

 the arch outwards. 



BRANCHES : 



(a) The recurrent branches (rami retrogradi, 

 Haller), from the upper concave side, ascend 

 and anastomose with the branches from the an- 

 terior carpal arch. 



(b) The superior perforating branches, three 

 in number, pass backwards through the upper 

 extremities of the last three interosseous spaces 

 to inosculate with the dorsal interosseous ar- 

 teries. 



(c) The palmar interosseous arteries, usually 

 three in number, but very liable to variation, lie 

 in front of the interosseous spaces, supply the 

 muscles there, and anastomose at the clefts of 

 the fingers with the digital branches from the 

 superficial arch. 



It is by an enlargement of these small vessels 

 that the deep palmar arch sometimes supplies 

 the corresponding digital arteries in the absence 

 of those usually derived from the superficial 

 arch. 



Fig. 280. DISSECTION OF THE LEFT ARM, SHOW- 

 ING AN ENLARGED MEDIAN ARTERY WHICH RE- 

 PLACES THE RADIAL AND ULNAR ARTERIES IN 



THE SUPPLY OF PALMAR DIGITAL ARTERIES TO 



HALF THE FINGERS (from Tiedemann). 



1, lower part of the brachial artery; 2, 

 radial artery, not giving any superficial volar 

 branch ; 3, recurrent radial branch ; 4, ulnar 

 artery passing superficially over the wrist and 

 supplying at 4', digital arteries to half the hand ; 

 5, the enlarged median artery passing in front of 

 the annular ligament of the carpus, and sup- 

 plying 5', digital vessels to the outer half of the 

 hand. 



VARIOUS CONDITIONS OF THE ARTERIES OF THE HAND. 



The arteries of the hand frequently vary from their usual mode of distribution, 

 (a) By far the larger number of deviations consist of a deficiency in either the 



