From the experimental evidence above, it is clear that in the upper four centimetres of the forearm the posterior interosseous nerve moves up to one centimetre or more medially relative to the radius on pronation of the forearm. This movement becomes of importance when considered in relation to methods of operative approach for excision of the radial head.

Operative approaches have been described in which emphasis has been placed on the position of incision, but in none of these is there any mention of the position of the forearm.

We suggest that the following precautions should be taken. 1) During excision of the radial head the forearm should be kept in full pronation. 2) The incision should be as posterior as possible to ensure that it is well clear of the nerve. 3) With the forearm pronated the incision extends from a little above the lateral epicondyle along the postero-lateral aspect of the forearm for not more than 5 centimetres; proportionately less in a child. 4) The surgical assistant's attention should be brought to the damage that the posterior interosseous nerve might sustain from undue pressure–for instance by retraction, especially by bone levers–in the anterior part of the wound.