[Paralysis of the interosseous nerve by a tendinous margin of the extensor carpi radialis brevis].

A 41-year-old woman was seen with a posterior interosseus nerve palsy. Exploration showed this to be caused by entrapment and neurotmesis of the posterior interosseus nerve under the tendinous margin of the extensor carpi radialis brevis muscle. One year after nerve reconstruction, the functional outcome was nearly normal.