Figure 2: Anteroposterior pelvis radiograph showed a dysplastic pelvis. The iliac crest showed a pathognomonic, semi lunar, irregular lacy margin with a wide irregular sacro-iliac joint. Note the supero-lateral collapse of the femoral heads bilaterally causing lateral displacement of the femoral heads (associated with epi-metaphyseal irregularities). Defective ossification of the acetabuli was evident.