After completing the arch, dorsal metacarpal artery continued as princeps pollicis artery for the thumb.
sup] About one-third of the SPA is formed by ulnar artery alone; the second-third by the superficial palmar branch of radial artery and the remaining third by arteria radialis indicis, a branch of either arteria princeps pollicis or the median artery.
After completing the arch, the first dorsal metacarpal artery continued as princeps pollicis artery for the thumb [Figure 1].
Thence it forms deep palmar arch in the palm after giving off the princeps pollicis
and radialis indicis artery.
As it runs through the anatomic snuffbox, it enters the palm between the two heads of the first dorsal interosseous muscle and then between the heads of the adductor pollicis muscle dividing into the princeps pollicis artery and the deep palmar arch.
The princeps pollicis artery descends along the ulnar border of the first metacarpal and divides into two proper digital arteries that run along each side of the thumb.
Volar advancement flaps are effective in the thumb because of the dedicated dorsal blood supply from the princeps pollicis artery.