Syndromes of compression of the median nerve in the proximal forearm (pronator teres syndrome; anterior interosseous nerve syndrome).

Entrapment of the median nerve in the proximal forearm is seen in two forms: the pronator teres syndrome, and the anterior interosseous nerve (or Kiloh-Nevin) syndrome. Both syndromes are rare, and they comprised approximately 1% of the compression syndromes of the upper limb which were treated operatively by the authors. The symptoms, signs, etiologies, and intraoperative findings are discussed. It is pointed out that certain of the clinical features may resemble those of irritation of the median nerve by a supracondylar process or Struthers' ligament. Although both proximal median entrapment syndromes have a favorable prognosis when treated non-operatively, the authors recommend operative treatment in cases in which there is no perceptible improvement following 8 weeks of non-operative treatment, since this is likely to speed and enhance recovery. Nine cases of the pronator teres syndrome (8 treated successfully by operation, 1 failure) and 2 cases of the anterior interosseous nerve syndrome (both fully recovered) are added to the cases reported previously in the literature.