Isolated complete denervation of the flexor pollicis longus.

Isolated complete denervation of the flexor pollicis documented by electromyography has not been reported. We report a healthy 26-year-old man who sustained a gunshot wound at the base of his left index finger. He reported ipsilateral flexor pollicis longus (FPL) paralysis one week later, after undergoing surgical exploration of the radial digital artery and nerve supplying the left index finger under axillary block anesthesia. Forearm pronation and distal interphalangeal flexion of the second through fifth digits were normal. Electromyographic findings revealed complete isolated denervation of the FPL. This represents a lesion involving the branch or branches of the anterior interosseous nerve to the FPL. The etiology was postulated to be either a direct injury secondary to intravenous catheter placement or an unusual presentation of neuralgic amyotrophy.