[Roentgen diagnosis of congenital hip dysplasia].

The X-ray of 4000 infants between the age of 4-6 months have been examined, regarding correlations between the measured Hilgenreiner's acetabular roof angle and the position of the pelvis during X-raying. Faulty positioning often was found, and only in 34,2% was the pelvis symmetric and the pelvic inclination normal, when the photos were made. The change of the acetabular roof angle due to the incorrect pelvic position is not always significant. The geometrical correction of these values is therefore not important and the other radiological signs of CDH can be relied on.