This occurs when a vertebrae has rotated and side flexed in relation to the vertebrae below; this is also called a malalignment in the spine, and therefore aggravates pain and restricts movement (Schamberger, 2013). This rotated segment may be in conjunction with a minor disc bulge.
This will induce a lateral shift in the spine as the combined movement carries the trunk with it
Men are more likely to shift than women; The majority (90%) shift away from the side of pain. A shift to the side of pain is more difficult to settle
This rotated segment may be in conjunction with a minor disc bulge- but not necessarily.
Schamberger W., 2013, The Malalignment Syndrome, diagnosis and treatment of common pelvic and back pain, 2nd Edition, Churchill Livingstone Elsevier, p: 141