The purpose of this report is twofold: first, to call attention to the possibility of traumatic dislocation of the hip occurring without rupture of the ligamentum teres; second, to record a typical case of aseptic necrosis and deformity of the head of the femur with its ligamentum teres intact and thoroughly vascularized, the pathologic condition having arisen from a traumatic interruption of the blood supply of the femoral head coming through the capsule of the hip joint. It had been my impression1that aseptic necrosis of the femoral head following a traumatic dislocation of the hip was the result of two factors: (1) rupture of the ligamentum teres during the dislocation, with consequent deprivation of its blood supply to part of the femoral head, especially to the summit of the head, and (2) too early weight bearing, with collapse of the osseous lamellas before adequate regeneration of bone. My