A rare anatomical variation of the course of the ulnar nerve

Tomonori Sato, Yukinobu Hirano

Abstract

A rare case of anatomical variation of the course of the ulnar nerve is presented. The variation consisted of the ulnar nerve piercing, and being tethered to, the fascia connecting the medial intermuscular septum and medial condyle of the right humerus. In addition, the nerve was also twisted as it pierced the fascia, at a distance of 65 mm proximal to the medial epicondyle. Such an anatomical variation of the nerve could potentially cause strain and mechanical damage to the nerve. An awareness of the possibility of such a variation may be of importance in the evaluation of entrapment neuropathy, because presence of such a rare variation could obscure the precise cause of the entrapment neuropathy.