Anterior interosseous nerve syndrome presenting with pronator teres weakness: a case report.

Anterior interosseous nerve syndrome (AINS) has been well described. A key muscle to examine clinically and on electromyography is the pronator teres, as this can differentiate between forearm and more proximal entrapment sites. We present a case of AINS with marked weakness and denervation of pronator teres. At operation the anterior interosseous nerve gave rise to the nerve to pronator teres and was entrapped by a fibrous band from the deep head of pronator teres.