Mechanical axis of lower limb extends from center of femoral head to center of ankle joint and passes near or through center of knee. It is in 3 degrees of valgus from vertical axis of body. Anatomic axis of femur is in 6 degrees of valgus from mechanical axis of lower limb and 9 degrees of valgus from true vertical axis of body. Anatomic axis of tibia lies in 2 to 3 degrees of varus from vertical axis of body.