Surgical anatomy of the radial nerve in the arm: a cadaver study

The purpose of this study was to analyse the anatomic course of the radial nerve (RN) in the arm, in order to minimize the potential risk of surgical injury.

The study was performed in 19 embalmed upper extremities of 11 adult human cadavers. We measured: distance from deltoid insertion (DI) into the humerus to lateral epicondyle (LE); distance from RN piercing point into the lateral intermuscular septum (LIS) to three other points-DI, LE and RN division into superficial and deep terminal branches; distance between the LE and the RN division. To assess variability, we correlated the distances between the landmarks to the overall length of the arm.

The RN was found to pierce the LIS within 31.6 mm of the most distal DI into the humerus. The mean distance between the entry point of RN in the LIS and the LE was 107.2 mm. The mean distance between RN perforating point in the LIS and RN division in its terminal branches was 86.4 mm. The DI-LE and the LIS-LE showed a moderate positive correlation with the length of the arm.

We describe the DI relationship to the RN course and also report its proportion within overall arm length which has not been previously described. Using the arm length as reference, our results show that RN can be found to perforate on the LIS at a point distal to the DI by 11% and proximal to the LE by 38%.