Thumb Radial Digital Artery, Thumb Ulnar Digital Artery, and Thumb Vein Exams

The princeps pollicis along with the radial digital artery of the index are both terminal branches of dorsal radial artery.
The princeps pollicis which is also called the first palmar metacarpal artery runs along the ulnar edge of the first metacarpal.
The princeps pollicis, the main artery of the thumb, is the origin of the radial and ulnar digital arteries of the thumb.
The radial and ulnar digital arteries of the thumb are too small to palpate on examination.
The radial and ulnar digital arteries of the thumb can be evaluated by Doppler exam.
The thumb’s vascular system also includes a superficial and deep venous system. The digital vena comitantes, which are variably presence, are too small to see or palpate on exam.

Diagrams & Photos

The princeps pollicis is the origin of the radial and ulnar digital arteries of the thumb.
Doppler assessment of the thumb radial digital artery distal to a palmar thumb laceration.

Key Points

The radial digital artery goes deep to the flexor pollicis longus and volar to the first metacarpal and along the radial side of the thumb between Grayson’s and Cleland’s ligaments.
Moberg advancement flaps are used to resurface palmar thumb deficits between 1 and 1.5 cm of the pulp. The Moberg flap contains both digital arteries, but the thumb continues to get its blood supply from the dorsal thumb digital arteries.
Position of the thumb on the hand and deep location of arteries can make anastomosis during replant difficult because it is difficult to get good visibility of the repair site. Some surgeons overcome this with a vein graft from the amputated tip to more easily approach the dorsal or palmar portion s of the main radial artery.
Because of its close proximity to the thumb metacarpal, the princeps pollicis is at risk for injury during closed reduction and pinning of metacarpal fractures.