Identification of the radial nerve during the posterior approach to the humerus: a cadaveric study

Identification of the radial nerve is necessary during the posterior approach to the humerus in an effort to maintain its integrity. Other than anatomic descriptions of the radial nerve with respect to osseous structures, there are few superficial intraoperative landmarks along the course of the traditional triceps-splitting approach to provide facile nerve identification. The objective of this study was to determine the reliability of using the anatomic intersection of the long and lateral heads of the triceps and the triceps aponeurosis as a superficial reference point for radial nerve identification during the posterior approach to the humerus.

Thirty adult human cadaver upper extremities as 15 matched pairs were used. Systematic identification and measurement from the point of intersection between the long and lateral heads of the triceps and the triceps aponeurosis to the distal most aspect of the radial nerve as it coursed the posterior humerus at its midaxial point was performed and recorded.

Mean distance was found to measure 39.0 ± 2.1 mm (range, 36-44 mm), approximating a fixed distance, two finger breadths proximal to our identified point of intersection. Statistical analysis between the two matched pair groups yielded no significant difference in measured distances (P = 0.88).

Our group has identified the point of intersection among three landmarks forming a point of intersection. This point is the confluence of the long and lateral heads of the triceps and the triceps aponeurosis. This serves as a visualized anatomic reference point during the posterior surgical exposure to the humerus and can be used to identify the radial nerve as it courses the posterior humerus.