Variations of the ulnar nerve and ulnar artery in Guyon's canal: a cadaveric study.

In 23 cadaveric hands the hypothenar region was studied and this report is about the anatomical boundaries and contents of Guyon's Canal. It was noted that the contents of Guyon's canal exit through two distinct areas termed the deep distal hiatus and superficial distal hiatus. A variation in the course of the deep branch of the ulnar artery, reported to be infrequent, was found to be present in 74% of the specimens. We concluded that the ulnar artery exists distal to the space described by Guyon. When a release of the ulnar nerve is undertaken, surgery should not only open the roof of Guyon's space but also the fibrous arcade of the deep distal hiatus.