The risk injury to the posterior interosseous nerve in standard approaches to the proximal radius: a cadaver study.

Purpose: The aim of this study was to provide guidance on the safe zones for the exposure of the proximal radius by measuring the distance from the PIN to various anatomical landmarks in the proximal forearm in pronation and supination.

Methods: Twenty cadaveric arms were used for this study. On the anterior aspect of the forearm, the distance between insertion of the biceps tendon and the arcade of Frohse as well as the shortest distance between the PIN and the ulnar aspect of the radial neck were measured. On the posterior aspect of the forearm, the shortest distance between the PIN and the ulnar border of the interosseous membrane was measured at 30 and 50 mm distal to the articular surface of the radial head.

Results: The distance between the PIN and ulnar aspect of the radial neck had a mean of 21.6 mm in supination and 13.3 mm in pronation. The distance between the radial tuberosity and the arcade of Frohse was 18.6 mm. The mean distance between the PIN and the radial border of ulna at 30 mm distal to the articular surface of the proximal radius was 12.3 mm in supination and 22.3 mm in pronation. At 50 mm distal to the articular surface of the proximal radius the mean distance was 8 mm in supination and 16.2 mm in pronation.

Conclusions: The course of this nerve is variable as it winds around the radial neck within the belly of the supinator muscle. Safe distances for dissection have been presented in our study.