Ten cases of de Quervain disease were examined by ultrasound. Three were treated with surgical method. Ultrasound examinations were performed with 7.5MHz transducers. We classified the patterns of the septum in the first extensor compartment of the wrist into three groups, complete type, incomplete type, and no septum type. According to this classification, seven cases were of the incomplete type, and the other three cases were of no septum type. Three cases treated with the operative method were of the incomplete type. Ultrasound examination seems to be useful for the diagnosis of the Quervain disease.
