Common variations of the radial writs extensors.

An anatomical study of the extensor carpi radialis longus (ECRL) and brevis (ECRB) in 173 upper limbs demonstrated abnormalities in 50%. Interconnecting tendons between the longus and brevis were found in 35% of limbs, the most common variation (26%) being a tendon arising proximally from the ECRL and inserting distally with the ECRB. In 42 limbs (24%) an extra muscle (the extensor carpi radialis intermedius) was present; many were large enough to activate a tendon transfer. Two case reports illustrate the use of extra muscles in the surgical rehabilitation of patients with paralytic disorders.