Close-up view of the right hip from an anteroposterior plain radiograph of a 19-year-old female with positive crossover sign. The point of crossover is marked by a blue dot. Arguably, the AIIS continues distally with round borders (black arrows) extending below the acetabular margin, potentially contributing to a false appearance of acetabular retroversion. Such a patient would require further investigation with computed tomography, to include 3-D imaging.