In other words, when the lumbar motion segment is rotated axially, it bends in the frontal and sagittal planes. This means that lateral bending moments are a function of axial rotation. Nm resulted in the motions shown. The coupled sagittal plane rotation is flexion at all levels. Applying the above information into the motion examination significantly changes one's interpretation of what is occurring in the patient's spinal movement patterns, both normal and abnormal.
Rotation is a coupled action of lateral flexion.
L3-L4 appears to be at the intersection point of two lateral bending actions. This, too is consistent with the work of White and Panjabi. Of this I have no quarrel. Rather, it may be a lack of understanding of the normal motions that the spine undergoes in real life. The above motions are but a few examples.