Fig. 1A–D.

AP radiographs of (A) a normal hip and three forms of abnormalities associated with mild slipped capital femoral epiphyses called (B) “flattening,” (C) the “bump,” and (D) the “hook.” Reproduced with permission from Harris WH. Etiology of osteoarthritis of the hip. Clin Orthop Relat Res. 1986;213:22.