Bilateral anomalous insertion of flexor pollicis longus.

A case of bilateral insertion of flexor pollicis longus to the proximal as well as the distal phalanges is reported. Initially, this case was diagnosed as congenital absence of the flexor pollicis longus, but surgery revealed an intact tendon, with the abnormality only present in the site of insertion. A survey of the literature on congenital abnormalities of flexor pollicis longus failed to reveal any reports of similar abnormalities.