de Quervain syndrome is stenosing tenosynovitis of the first dorsal compartment of the wrist, which contains the abductor pollicis longus (APL) and the extensor pollicis brevis (EPB) tendons. The condition is named for the Swiss surgeon Fritz de Quervain, who described in 1895 a painful condition involving the APL and the EPB tendon sheaths at the radial styloid process. de Quervain recommended simple release of the stenotic extensor retinaculum.