Abstract
Motions of the femur・pelvis and the sacroiliac joint・lumbosacral joint・lumbar facet joints were analyzed by MRI in 6 positions of an extremity, i.e., in a prone position with no hip extension, in 3 prone positions with the hip extension of 5°, 10°, and 15° (the knee extended), and 2 prone positions with a load of 10N・m and 20N・m being applied to a distal portion of femur from the hip extension of 15° (the knee extended). The subjects were 24 healthy individuals [12 males (mean age: 21.3 years) and 12 females (mean age: 20.6 years)]. Consequently, in all the subjects, as the degree of hip extension increased, femoral extension relative to the pelvis and anterior pelvic tilt increased. Also nutation of the sacroiliac joint on the side of the non-extended hip increased, and extension of the 3/4 and 4/5 lumbar facet joints and lumbosacral joint increased. However, motions of all sites excluding the 3/4 lumbar facet joints between the 10N・m load application and the 20N・m load application were recognized only in the female subjects. These results clarified normal motions of each joint which composes the lumbopelvic-hip complex during passive unilateral hip extension.
