A rare case of a short radiocarpal flexor (M. flexor carpi radialis brevis vel profundus of Wood) was found on the right forearm of a 47-year-old Japanese male corpse. The muscle arose from the anterior surface of the radius, ran distally in the deep layer of the flexor region to enter deeply into the carpal tunnel, and then interconnected with the subtendon of the extensor carpi radialis brevis at the gap between the bases of the second and third metacarpal bones. This muscle was supplied by a branch of the anterior interosseous nerve.