Ultrasonographic classification of hip dysplasia. A, Image is rotated 90 degrees clockwise to resemble a hip in the anteroposterior plane in a standing or supine child. Angleαis formed by the intersection of the baseline and the acetabular roofline; it is normally greater than 60 degrees. Angleβis formed by the intersection of the baseline and the inclination line; it is normally less than 55 degrees. In a normal hip, the baseline should bisect the femoral head. B, Ultrasound appearance of a normal hip:αangle of 60 degrees and baseline bisects the femoral head. C, Dislocated hip.