The amazing strength and flexibility of the spine is due in large part to the unique interaction of the disc in the front portion of the spinal column with the facet joints in the back portion of the spinal column. Spinal facet joints are true “synovial joints.” Like the shoulder and the knee, spinal facet joints have a joint capsule lubricated with fluid and a network of pain-sensitive nerve fibers. Facet joints are numerous, with two at each spinal level. These small, delicate joints are prone to injury, deterioration, and inflammation, and they sometimes become sources for chronic neck and back pain independent of intervertebral discs and spinal nerves.
ORIGINS OF FACET JOINT PAIN
Facet joints become especially vulnerable when the intervertebral disc has been injured. This is true because as the disc degenerates, the volume of the disc space is reduced and tends to flatten out. The disc therefore loses height and the space between the vertebral bodies becomes narrowed. The flattening disc space provides much less support for the facet joints at that particular level, and the joints become subject to increased stress. Facet joint pain is often felt in the spinal area rather than in an arm or leg.
Just as epidural injections are used to treat disc-related pain within the spinal column, facet joint injections are sometimes used to diagnose and treat pain emanating from the facet joints. Injections of steroids directly into the facet joints may reduce pain and facilitate rehabilitative therapy.