D. Have a subject sit astride in a chair (with no arms) with hands at the neck (as if doing a sit up), then rotate the trunk as far as possible from side to side.
Report the regions of the spine as to rotating ability.
Report the variations in spinal mobility at the different regions of the spine.
The movement of the hands to the back of the neck involves relatively low muscle activity in both rectus abdominus and in all right side muscles except the internal oblique. During rotation of the torso in a clockwise direction the left external oblique and right internal oblique muscles ...