[Sonography of the knee extensor system].

In standardised ultrasound examination of the knee joint, ventral, medial, lateral and dorsal sectional planes are used. Sonographic examination of the knee joint can supply important information on many pathological alterations of the periarticular soft-tissues. Since complete diagnostic examination of the bony structures of the joint by ultrasound is not possible, radiological examination in two sectional planes cannot be replaced by this modality.