This is an interesting article on facet syndrome which can be associated with whiplash injuries.
Steven C. Ludwig, M.D., Chief of Spine Surgery, University of Maryland Medical Center
January 4, 2008
Question: What Is Facet Syndrome?
Answer: Facet syndrome is a condition in which the joints in the back of the spine degenerate and subsequently cause pain.
The facet joints are found at every level on both sides of the lumbar spine. They provide about 20 percent of the twisting stability in the low back. Each facet joint is positioned at each level of the spine to provide the needed support especially with rotation.
Facet joints also prevent each vertebra from slipping over the one below. A small capsule surrounds each facet joint providing a nourishing lubricant for the joint.
Also, each joint has a rich supply of tiny nerve fibers that provide a painful stimulus when the joint is injured or irritated. Inflamed facets can cause a powerful muscle spasm.