Lumbar spinal manipulation, or chiropractic adjusting, is thought to separate the surfaces
of the spinal joints and thereby relieve lower back pain. This study will use MRI scans to
evaluate the spinal joints before and after spinal manipulation.
Zygapophysial joints, better known as facet or “Z” joints, are located on the back
(posterior) of the spine on each side of the vertebrae where it overlaps the neighboring
vertebrae. Z joints provide stability and allow the spine to bend and twist. Adhesions in
the Z joints may develop following hypomobility of vertebrae. These adhesions may be
alleviated by separation (gapping) of the Z joints.
Side posture adjusting (spinal manipulation) is thought by many to gap the Z joints, yet no
measurable differences of the Z joints before and after spinal manipulation have ever been
published. This study will evaluate gapping of the L3/L4, L4/L5, and L5/S1 Z joints by
taking measurements directly from MRI scans of the Z joints before and during positioning
for a side posture adjustment, and before and after side posture adjusting.
Health volunteers will be randomly assigned to one of four groups: 1) neutral position
followed by side posture positioning (trunk rotated to the volunteer’s right); 2) neutral
position followed by side posture spinal adjusting followed by neutral positioning; 3)
neutral position followed by side posture spinal adjusting, followed by side posture
positioning; and 4) neutral position followed by neutral position (control group). MRI scans
will be taken with the volunteers in the original neutral position and in the final position
(either second neutral position or side posture positioning).
- Student at the National University of Health Sciences
- 185 pounds or less for males and 145 pounds or less for females
- No previous history of lower back pain lasting more than 2 weeks, or no more than
three episodes of back pain of brief duration (1 to 2 weeks) in any given year
- History of lower back pain
- Presence of disc degeneration, significant osteoarthritis, scoliosis of greater than
20 degrees (Cobb's angle), or other significant pathology seen on x-rays
- Positive findings on orthopedic or neurologic test
- Inability of the examining chiropractor to obtain articular releases (audible pop)
during lumbar side posture adjustment given at the conclusion of the examination