The lumbar paravertebral musculature, the M. quadriceps femoris and M. triceps surae of boys suffering from Duchenne's muscular dystrophy of different clinical progression, were examined via sonography. The sonographic incisions were made at fixed levels. The sonographic findings were compared with those of healthy boys. The sonographic findings showed - depending on the clinical stage of Duchenne's muscular dystrophy - typical reflex patterns of different intensity determined by lipomatosis and fibrosis of the skeletal musculature, correlating with the clinical stage, and hence musclesonography is an important diagnostic element in the observation of the course and in therapy planning in Duchenne's muscular dystrophy. The 7-MHz transducer has an advantage over the low-frequency transducers mostly in use, because the image quality is substantially superior.