Bilateral anatomical variations in the first extensor compartment of the wrist and it’s clinical importance.

Abstract

Variations of the muscles and the tendons of the hand and the wrist are extremely important in hand surgery practice. The variety in the number of tendons and sites of insertion of the abductor pollicis longus (APL) and extensor pollicis brevis (EPB) muscle has been described in detail. The present case reports an unusual fusion of muscle bellies of abductor pollicis longus and extensor pollicis brevis with three separate tendons of insertion, the two tendons inserted into the base of first metacarpal and to proximal phalanx. The third tendon coursed in the narrow fibrous tunnel formed in the wrist and inserted on the base of the proximal phalanx. Awareness of these variations are critical when decompressing the first compartment for de Quervain’s tenosynovitis or when selecting a tendon slip for transfer.