Unilateral occurrence of extensor medii proprius: an incidental finding

The deep extensors muscle of forearm may contain inconsistent muscles like extensor digitorum brevis manus (EDBM), extensor medii proprius (EMP), extensor indicis et medii communis (EIMC) and anomalous extensor indicis proprius (aEIM). We report a rare case of EMP with its unusual course in insertion along with co-existence of extensor indicis proprius muscle (EIP). It originated along with EIP from the distal third of dorsum of ulna and adjacent interosseous membrane, just distal to extensor pollicis longus (EPL). Distally the tendon of the muscle merged with extensor expansion at metacarpophalangeal joint of third digit deep to the extensor digitorum tendon. The knowledge of such variations on the hand is essential to the clinicians and surgeons as hand injuries are one of the most common injuries occurring due to its superficial location and poor insulation. Additionally, this information may help them in accurate diagnosis and management of functional deformities, pathological lesions and various other disorders of hand.