Duplicated superficial branch of the radial nerve and brachioradialis muscle belly: prevalence and significance.

Abstract

The superficial branch of the radial nerve (SBRN) is a sensory nerve innervating the dorsoradial part of the hand. It originates in the cubital fossa, runs under the belly of the brachioradialis muscle (BM), emerges from underneath in the distal third of the forearm and continues in the subcutaneous tissue towards the hand. There exist several anatomical variations of its branching and course, including a rare variation of its duplication combined with a duplication of the brachioradialis muscle belly. The aim of this study was to find out the prevalence of this variation on a sample of cadaveric human bodies which has not been reported yet. We have carefully dissected 208 cadaveric upper limbs (Central European population). All cases of limbs containing the variation of a double SBRN and/or a double BM belly were measured and documented. We have identified 2 cases of a double SBRN combined with a double BM belly (0.96%). Both were present in the right forearm of a male donor and in both cases the nerve was impinged by muscle bundles connecting the 2 muscle bellies together. Moreover, we have encountered 1 case of a double SBRN without a double BM belly (0.48%), i.e. the total prevalence of a double SBRN was 1.44%. The duplicated SBRN with the duplicated BM is a relatively rare anatomical variation that might cause complications while performing various surgical procedures in the forearm, moreover it might be a rare cause of Wartenberg's syndrome.