Aim: Hypothenar vascular anatomy has been approached by several authors due to its importance in flap design. The aim of this research is to describe the vascular anatomy of the proximal hypothenar eminence (HE), focusing on a cutaneous branch (CB) of the deep ulnar artery and its possible applications to flap designs. Materials and Methods: Fourteen fresh-frozen hands were studied. Red latex solution was injected previous to dissection. Gross dissection was performed under 3× to 6× magnification. The HE was approached through a longitudinal incision at the fourth web space line reaching the proximal wrist crease. A CB of the deep ulnar artery was identified. Its anatomic variations and relationship to the ulnar nerve were registered as well as its anatomic territory. A theoretical flap was designed and transposed to the volar aspect of the wrist and the interthenar region. Results: A constant CB was identified in the sample. Its origin was at the anteromedial aspect of the deep ulnar artery on the first segment of the artery. At this point, the deep ulnar artery passed over the ulnar nerve and the ulnar digital nerve of the fifth finger in 9 of 14 cases. In the remaining 5 cases, the deep ulnar artery passed behind the nerve; in 4 of these cases, the CB passed behind the nerve as well. In 1 case, the deep ulnar artery passed behind the ulnar nerve, but the CB passed over it. The deep ulnar artery origin was located at a mean of 9 mm distal to the pisiform (range, 3-12 mm). The CB origin was identified at a mean of 3 mm distal to the deep ulnar artery (range, 1-6 mm). The CB irrigated the supra-aponeurotic aspect of the proximal half of the HE by 3 to 5 collateral branches. The arterial diameter at its origin was 0.4 mm average and the distance between the origin and the first collateral branch was 9 mm average. This study shows that it is feasible to harvest a hypothenar cutaneous flap based on the CB. This flap may measure up to 7 × 3 cm. We also showed that it could be rotated as a propeller flap to cover a volar interthenar and wrist skin loss or a resected fibrosis. The donor area could be close by first intention. Conclusion: A constant CB from the deep ulnar artery was identified. This artery supplies the proximal half of the HE and features connections proximally and distally. In spite of the anatomic variations of the deep ulnar artery, in almost all of the cases the CB passed anterior to the ulnar nerve. According to the results of this research, a flap based on this CB may be raised to cover the volar wrist and palm in case of recalcitrant carpal tunnel and other deficits of coverage tissue.