Bilateral extensor indicis brevis: a rare muscular variant.

Variants on muscles and tendons of the forearm or hand occur frequently in human beings. They are often discovered during educational cadaveric dissections and surgical procedures. Knowledge of such anomalies is necessary to the surgeons in order to avoid possible damage to adjacent muscles' tendons' blood vessels or nerves. Here we describe a rare muscular variant, the extensor indicis brevis originating from the ligaments of the proximal row of dorsal carpal bones.