The role of the iliopsoas muscle in femoral rotation

Summary  THE axis of femoral rotation in the anatomical position is a line joining the centre of the head of the femur to the middle of the intercondylar fossa. The relationship of the iliopsoas to this axis was studied in eleven specimens with the femur unrotated, medially and laterally rotated in the fully flexed, extended and ‘resting’ positions. The mean angle between the psoas tendon and the plane of rotation was significantly decreased by flexion and increased by extension but remained unaltered by medial and lateral rotation. In all but three instances the axis of rotation passed through the iliopsoas. These results suggest that the iliopsoas does not play a significant part in the rotation of the normal femur.