A variant of the extensor medii proprius (EMP) was identified during routine dissection of the left hand of a 67-year-old female cadaver. The flat, fleshy muscle originated from the lunate bone, narrowed into a flat tendon near the 3rd metacarpophalangeal joint, and continued distally to insert on the extensor expansion of the 3rd digit. A branch from the posterior interosseous nerve was traced to the EMP. We propose that this previously unreported variation be termed extensor medii proprius brevis (EMPB).
