Normal axial anatomy of the hip as demonstrated by computed tomography.

The anatomy of four baseline transaxial computed tomography (CT) slices of the hip is described and compared with the corresponding anatomical cuts in cadavers. Level I demonstrates the superior compartment of the joint and the superior aspect of the femoral head. Level II is clinically the most important in that it demonstrates the bone thickness of the medial acetabular wall. Level III is through the femoral neck and allows measurements of femoral anteversion and acetabular inclination. The fourth level demonstrates the calcar femorale, but is seldom performed. An easy method of achieving reference levels II and III without a survey radiograph is described; the radiation dose can therefore be reduced by performing only the clinically relevant slice.