Facet joint syndrome is pain at the joint between two vertebrae in your spine. Another term for facet joint syndrome is osteoarthritis.
The facet joints are the joints in your spine that make your back flexible and enable you to bend and twist. These joints also keep the back from slipping too far forward or twisting without limits. The nerve roots pass through these joints to go from the spinal cord to the arms, legs and other parts of the body. Nerves exit your spinal cord through these joints on their way to other parts of your body. Healthy facet joints have cartilage, which allows your vertebrae to move smoothly against each other without grinding. Each joint is lubricated with synovial fluid for additional protection against wear and tear.
When these joints get swollen because of injury or arthritis, it causes pain. If the affected joint is in the neck, it may cause headaches and difficulty moving the head. If it is in the back, it may cause pain in the lower back, buttocks or thighs.
Facet joint syndrome can be caused by a combination of aging, pressure overload of your facet joints, and injury.
Pressure overload on your facet joints is probably caused by degeneration of the intervertebral discs in your spine. As the discs degenerate, they wear down and begin to collapse. This narrows the space between each vertebra. This narrowing of the space between each vertebra affects the way your facet joints line up. When this occurs, it places too much pressure on the articular cartilage surface of the facet joint. The excessive pressure leads to damage of the articular surface and eventually the cartilage begins to wear away.
When facet joint arthritis gets bad enough, the cartilage and fluid that lubricate the facet joints are eventually destroyed as well, leaving bone rubbing on bone. Bone spurs begin to form around the facet joints. When bone spurs develop, they can take up space in the foramen (the opening between vertebrae where nerve roots exit the spine) and press into nerve roots. As the bone spurs begin to grow larger, they can eventually extend into the spinal canal itself. This leads to narrowing of your spinal canal, called spinal stenosis.