Anatomical study of the ulnar dorsal artery and design of a new retrograde ulnar dorsal flap

Background: The purpose of this article is to describe a new flap that resulted from a study of the vascular distribution of the ulnar dorsal artery. The study was directed toward the distal and proximal branches with their anastomoses. Methods: Green latex was injected into the brachial artery of the proximal limbs of 25 cadavers. After 48 hours, dissection of the vessels was performed beginning at the ulnar dorsal artery and following its descending and ascending branches. In two of the specimens, an injection of methylene blue was administered in the ulnar artery to look for reverse flow from the descending branch. Results: The ulnar dorsal artery was located in all injected limbs with a constant distribution. It had two branches: a descending one that distributed under the abductor digiti quinti muscle and anastomosed with a deep branch of the ulnar artery, and an ascending one supplying the proximal third of the forearm. Retrograde flow in the descending branch was found by injecting dye. Conclusions: Based on these findings, a flap with reverse flow that the author called a "retrograde ulnar dorsal flap" was designed at the expense of the descending branch by ligating the ulnar dorsal artery where it originates. This makes it possible to cover soft-tissue defects that are more distal on the hand.