Anatomic study of the innervation of Extensor Carpi Radialis Longus and Extensor Carpi Radialis Brevis. Interest in nerve transfers.

Purpose: This study pretends to describe the innervation pattern of Extensor Carpi Radialis Longus (ECRL) and Extensor Carpi Radialis Brevis (ECRB) to use ECRL branches as a first choice in nerve transfers to restore flexion and extension of wrist and fingers due to its easier identification and its redundant innervation. Methods: 9 cryopreserved and anonymous specimens were dissected to identify the radial nerve and describe the number of branches, distance between its origin and a line connecting both epicondyles, length of each branch and type of innervation of ECRL and ECRB according to Taylor’s classification. Results: 6 out of 9 specimens presented two branches from the radial nerve to innervate the ECRL (Taylor type 3). 3 out of 9 specimens only had one branch to innervate the ECRL, originating from the radial nerve (two of them classified as a Taylor type 1 and the other as a Taylor type 2). All the specimens had only one branch to innervate the ECRB (eight showing a Taylor type 1 pattern, and one classified as Taylor Type 2); in 7 out of 9 this branch emerges from the deep branch of the radial nerve, emerging in the other 3 specimens from the superficial branch of the radial nerve. Conclusion: The use of the ECRL branches could be considered as the first choice in nerve transfers to restore the flexion and extension of elbow, wrist and fingers in nerve injuries, because of its constant origin after the brachioradialis branch and in most of the cases its redundant innervation.