Unilateral anomalous brachial and antebrachial musculature associated with duplication of anterior interosseous nerve: a case report.

The present case aims to provide an accurate anatomical description of coexistent accessory heads of flexor pollicis longus in the arm and forearm, extra muscular slips of the accessory belly of flexor pollicis longus to flexor digitorum profundus, and double anterior interosseous nerves. The morphology of the anomalous accessory muscle bellies is correlated with their clinical significance and embryological basis. Knowledge of such muscular and neuroanatomical variants is imperative prior to traumatic evaluation and reconstructive surgery.