Accessory head of the extensor carpi radialis longus muscle merging with extensor carpi radialis brevis muscle.

PURPOSE: The retention and capture functions of hand can be achieved by the consistent manner work of the extensor and flexor muscles. Therefore, it is important to know variations of the extensor and flexor muscles.

METHODS: During an educational dissection, accessory heads of the extensor carpi radialis longus muscle were found on the right side in a Korean cadaver.

RESULTS: The extensor carpi radialis longus muscle was originated from the lateral supracondylar ridge of the humerus and trifurcated into three heads as lateral, intermediated, and medial heads. The lateral and intermediated heads merged and inserted to the base of the second metacarpal bone. However, medial head of extensor carpi radialis longus muscle was merged with the extensor carpi radialis brevis muscle.

CONCLUSIONS: Knowledge of the variations of the ECRL is important for surgeons because the presence of the ECRL variations increases the incidence of iatrogenic injuries during surgery and invasive procedures.