The dorsal flap of the first web.

In the first web space region, there are communications between the dorsal arteries which arise from the dorsal branch of the radial artery and the digital arteries of the thumb and the index finger. These allow a distally based flap to be raised in the first dorsal intermetacarpal area. This flap has been used in 15 cases of soft-tissue loss from the thumb and index finger. The donor sites were closed primarily in all but two patients. There were no complications, and the results show that this flap is useful for soft-tissue defects on the tip and the palmar and dorsal surfaces of the thumb. Moreover, it may be used as a "cross-finger" flap.