The risk injury to the posterior interosseous nerve in standard 3 approaches to the proximal radius : a cadaver study 4 Nima Heidari

8 Abstract 9 Purpose The aim of this study was to provide guidance 10 on the safe zones for the exposure of the proximal radius by 11 measuring the distance from the PIN to various anatomical 12 landmarks in the proximal forearm in pronation and 13 supination. 14 Methods Twenty cadaveric arms were used for this study. 15 On the anterior aspect of the forearm, the distance between 16 insertion of the biceps tendon and the arcade of Frohse as 17 well as the shortest distance between the PIN and the ulnar 18 aspect of the radial neck were measured. On the posterior 19 aspect of the forearm, the shortest distance between the 20 PIN and the ulnar border of the interosseous membrane 21 was measured at 30 and 50 mm distal to the articular 22 surface of the radial head. 23 Results The distance between the PIN and ulnar aspect of 24 the radial neck had a mean of 21.6 mm in supination and 25 13.3 mm in pronation. The distance between the radial 26 tuberosity and the arcade of Frohse was 18.6 mm. The 27 mean distance between the PIN and the radial border of 28 ulna at 30 mm distal to the articular surface of the proximal 29 radius was 12.3 mm in supination and 22.3 mm in prona30 tion. At 50 mm distal to the articular surface of the prox31 imal radius the mean distance was 8 mm in supination and 32 16.2 mm in pronation. 33 Conclusions The course of this nerve is variable as it 34 winds around the radial neck within the belly of the supi35 nator muscle. Safe distances for dissection have been 36 presented in our study. 37 38