When performing an anteroposterior (AP) projection of the femur, how much and in which direction should the femur be rotated?

When performing an anteroposterior (AP) projection of the femur, the correct approach involves rotating the femur 10-20 degrees medially. This medial rotation is important for several reasons. It places the femoral neck in profile and ensures that the entire femur is well visualized on the radiograph. By rotating the femur medially, this technique helps to prevent the neck of the femur from being foreshortened, which could lead to a misinterpretation of the femur's anatomy and any potential pathologies.

This medial rotation aligns the long axis of the femoral head with the film, producing a clearer image that facilitates accurate assessment and diagnosis. Such positioning is critical in radiographic practices, as it enhances image quality and diagnostic utility, making it easier for clinicians to evaluate the condition of the bone structures involved.