An unusual variation of abductor digiti minimi manus and its clinical significance

The abductor digiti minimi manus muscle usually has two heads and two insertions, often close to each other. Accessory bellies of this muscle have been vastly described in anatomy textbooks. During routine dissection of an adult male cadaver left forearm and hand we observed a rare variation of this muscle, in which there was an accessory muscle band which originated from the palmaris longus muscle tendon and traversed through the Guyon’s canal, an anatomical tunnel that is occupied by the ulnar nerve and artery. This type of anatomic variation is often associated with ulnar tunnel syndrome, in which the accessory belly is the source of a neurovascular compression causing pain, weakness of the muscles in the hand, and loss of motor and sensitive functions