Fig. 1From: Cam morphology and inguinal pathologies: is there a possible connection?The crossover sign (COS) in a patient with the pincer morphology (overlap between the anterior and the posterior walls of the acetabulum). In a hip with normal anteversion, the line of the anterior wall lies medial to the line of the posterior wall, while the line of the posterior wall crosses the line of the anterior wall in acetabular retroversionBack to article page