The normal acetabular rims are shown in grey lines. 

Cross sign or X-sign meaning that at mid-point of femoral head; the anterior line (that should be medial) superiorly crossing to be lateral to posterior superior line (that should be lateral). This is seen in FAI (femoroacetabular impingement) due to acetabular retroversion.

Wiberg angle (red lines) should be between 25 and 40 degrees. In protrusio acetabuli it exceeds 40 degrees.