Fig. 3From: Magnetic Resonance Arthrography, a valuable pre-operative imaging modality in femoro-acetabular impingementa A line joining anterior and posterior bony rim-do not include labrum. This is the rim line (dotted). Then, b draw another line parallel to the above that passes through the center of the head. This is the center line. Normally rim line should be lateral to center line (measure in mm with a + sign)Back to article page