The femoral mechanical axis runs from which to which landmark?

• A. From the head of the femur to the intercondylar notch of the distal femur
• B. From the femoral head to the intercondylar fossa
• C. From the femoral neck to the intercondylar notch
• D. Runs from the head of the femur to the intercondylar notch of the distal femur

Answer: (D)

The femoral mechanical axis is the straight line that reflects overall femoral alignment, running from the center of the femoral head down to the knee joint center. In practice, that knee center is approximated by the intercondylar notch of the distal femur. So the axis goes from the head of the femur to the intercondylar notch of the distal femur. Starting at the femoral neck or aiming at the intercondylar fossa would not describe the true axis, since the neck is not the axis origin and the fossa is a different posterior landmark, not the knee center.