Junctura tendinum between extensor digitorum communis and extensor pollicis longus.

A junctura tendinum was incidentally identified between the extensor digitorum communis of the index finger and the extensor pollicis longus in a 34-year-old woman. This tendinous interconnection did not represent a supernumerary muscle. Examination of the patient suggested that this anomaly was probably bilateral since she lacked independent extension of the thumb and fingers in both hands. This anatomic variant has not previously been reported.