dorsal carpal branch of the radial artery dorsal carpal branch of the radial artery the dorsal carpal branch of the radial artery (posterior radial carpal artery) is a small vessel which arises beneath the extensor tendons of the thumb; crossing the carpus transversely toward the medial border of the hand, it anastomoses with the dorsal carpal branch of the ulnar artery. dorsal carpal branch of the radial arteryarteries of the back of the forearm and hand.detailssourceradial arterybranchesdorsal carpal arch, dorsalis pollicis, princeps pollicis arteryidentifierslatinramus carpalis dorsalis arteriae radialista98a12.2.09.032ta24646fma22755anatomical terminology the dorsal branch of the radial artery also branches into the dorsalis pollicis artery; more distally it branches into the princeps pollicis artery, and anastomoses with perforating branches of the deep palmar arch