Which anatomical landmark on the proximal femur provides insight into its degree of rotation?

• A. Greater Trochanter
• B. Lesser Trochanter
• C. Femoral Head
• D. Femoral Neck

Answer: (B)

The anatomical landmark on the proximal femur that provides insight into its degree of rotation is the lesser trochanter. The position of the lesser trochanter is critical for assessing femoral rotation, as it is situated on the posteromedial aspect of the femur. When analyzing the femur, particularly in imaging or surgical contexts, the orientation of the lesser trochanter in relation to the greater trochanter and the femoral head helps to determine whether the femur is in anatomic, internal, or external rotation.

The lesser trochanter’s position can change with different degrees of rotation. In neutral rotation, the lesser trochanter is seen less prominently on standard anterior-posterior X-rays. However, as the femur rotates internally, the lesser trochanter becomes more visible, indicating the degree of internal rotation. Conversely, in external rotation, the lesser trochanter's visibility decreases. This makes it an essential landmark for radiologists and orthopedic surgeons when evaluating the alignment and rotation of the femur.

Other structures such as the greater trochanter, femoral head, and femoral neck have their own importance in the anatomy of the hip, but they do not provide as direct an assessment of rotational alignment as the lesser