ANATOMY OF THE POSTERIOR INTEROSSEOUS NERVE IN RELATION TO FIXATION OF THE RADIAL HEAD

The relationship of the posterior interosseous nerve to the radial nec k as it relates to internal fixation of radial head fractures was stud ied in 50 fresh anatomic specimen arms, After a standard posterolatera l approach, blind subperiosteal dissection was performed distally unti l a 4-cm minifragment plate could be placed on the shaft of the radius , Dissection of the radial nerve was performed under loupe magnificati on, In only one (2%) arm did the posterior interosseous nerve lie dire ctly on the radius, The average distance from the posterior interosseo us nerve to the plate was 5 +/- 1.2 mm, The nerve was not damaged by p lacement of the plate in any case, In two (4%) cases the nerve lay on top of the distal portion of the plate within the supinator with the f orearm in neutral rotation. The average distance from the radial head to the origin of the posterior interosseous nerve was 1.2 +/- 1.9 mm, with the takeoff being proximal to the radial head in 31 cases, The mu scular branch to the extensor carpi radialis longus was located 7.1 +/ - 1.8 mm from the radial head, These findings suggest that pronation o f the forearm with blind subperiosteal dissection for plate placement does not place the posterior interosseous nerve at significant risk fo r structural injury, However, as with any approach done in the region of the nerve, caution should be used to avoid tension on the nerve tha t could lead to physiologic injury.