Targeting the radial nerve in upper limb spasticity: a surgical anatomy guide.

purposeThe radial nerve is of particular importance in the spastic upper limb, as it innervates muscles that frequently exhibit spasticity as well as muscles that are often paretic. This study describes its anatomy at the elbow, to provide a surgical reference for selective neurectomy or nerve transfers in spasticity treatment.

methodsThe radial nerve of sixteen fresh cadaveric upper limbs was dissected from the distal end of the radial groove to the point where the posterior interosseous nerve (PIN) runs within the supinator muscle. All branches were identified and documented.

resultsThe branching order, based on the mean distance from the lateral epicondyle to the first branch innervating each muscle, was: brachialis, brachioradialis, extensor carpi radialis longus (ECRL), superficial branch, supinator muscle, extensor carpi radialis brevis (ECRB). A branch to the brachialis muscle originating from the radial nerve was present in 9 out of 16 specimens (56%). The brachioradialis muscle typically received two branches from the radial nerve, always arising proximal to the bifurcation into the superficial and deep branch and proximal to the ECRB branch. The ECRL was usually innervated by one or two branches, sharing a common origin with the brachioradialis or ECRB in over half of the specimens. The ECRB was innervated by a single branch, originating from the superficial branch in 7/16 cases (44%).

conclusionAlthough the radial nerve at the elbow exhibits considerable variability, this study can provide an anatomical framework for surgical planning in selective neurectomy and nerve transfer procedures targeting the radial nerve.