Background: Several studies have identified the radial nerve in arm using different anatomic landmarks, however, a
controversy remains. Deltoid tuberosity (DT) and brachioradialis (BR) are reproducible landmarks that can be used to
identify the radial nerve (RN) during fracture surgery.
Methods: Dissection of RN was carried out in 17 fresh frozen adult cadavers. Using a calibrated caliper, we measured
the distance between DT and the origin of BR. The distance between DT and where RN becomes lateral in its relationship
with the humerus (DT-RN) and the distance between RN and BR (RN-BR) were subsequently measured. The ratio of
DT-RN to DT-BR was calculated to see where the nerve lies in relationship to DT-BR.
Results: Average DT-BR was 81.8 (±14.86) mm, average DT-RN was 48.9 (± 7.83) mm, and average RN-BR was 33.0
(± 10.16) mm. RN was always found posterior to DT and was never found in the proximal third of DT-BR. The nerve
was found in the middle third of DT-BR in 14 of 17 cadavers (82.4 %) and in the distal third in 3 out of 17 cadavers
(17.6%). 16 of 17 cadavers (94%) had radial nerve in the distal half of DT-BR.
Conclusion: Using the anatomic relationships between RN, DT, and the origin of BR, identification of RN is easily
reproducible. These two structures can serve as the stationary landmarks during fracture surgery to find the radial
nerve, which can be found in the distal 2/3 of the distance between the deltoid tuberosity and the origin of brachioradialis.
Level of evidence: V