An anomalous bilateral muscle in Guyon's canal found during cadaver study.

During anatomical dissection, an unusual bilateral muscle in the region of Guyon's canal was found in a 29-year-old human male cadaver. It originated from the pisiform bone and inserted to the flexor retinaculum. The muscle passed between the superficial and deep branch of the ulnar nerve. The ulnar artery passed anteriorly to the muscle. This work reports this finding and tries to categorize it in one of the groups following the literature.