Ulnar dorsal digital artery

The ulnar dorsal digital artery of the pollex (Ulnodorsal digital artery of the thumb; UDDAT) is a small artery that courses along the dorsoulnar aspect of the thumb, providing arterial blood supply to the skin and soft tissues on the dorsal and ulnar side of the thumb.

Anatomical Description

This artery runs on the dorsoulnar border of the thumb, connecting the region of the first metacarpal head to the dorsal arcade of the proximal nail fold. It is one of four arteries that typically supply the thumb, alongside the ulnopalmar digital artery (UPDAT), the radiopalmar digital artery (RPDAT), and the radiodorsal digital artery (RDDAT).

Origin and Prevalence

The ulnodorsal digital artery of the thumb is present in approximately 83–100% of hands. Its most common source is the first palmar metacarpal artery (princeps pollicis artery), from which it originates in roughly 57–73% of cases. It may also arise from the first dorsal metacarpal artery (~21% of cases) or, less frequently, from perforating branches at the level of the first metacarpal neck. The princeps pollicis artery gives rise to this dorsal vessel through a perforating branch that traverses from the palmar to the dorsal side of the thumb at the metacarpal neck level.

Course and Relationships

The artery travels along the dorsoulnar surface of the thumb, superficial or deep to the fascia, and terminates by contributing to the dorsal vascular network of the thumb, including anastomoses with the dorsal arcade at the nail fold. It communicates with the palmar digital arterial system through multiple anastomotic connections, creating a robust collateral network.