Causes of Facet Joint Pain
Before you can understand facet pain causes, it may help to understand how the facet joints function in your spine. The spine is made up of many interlocking bones, called vertebrae. Between each of these bones is an intervertebral disc, designed to cushion the bones from shock and allow the spine to bend and twist. Because the spinal cord also runs behind and through the spinal vertebrae, it is important to make sure the spine doesn’t twist or bend too far—this is the job of the facet joints. Together, the disc and the facet joints create a “three-joint complex”: they work together to allow just the right amount of movement.
The official name for the facet joint is the zygapophysial joint. There are two facet joints located between and behind each of the vertebrae in your spine, connecting the bones to each other. Like other joints, the facet joint bones are covered in cartilage to help protect them during movement. There is also fluid between the bones for lubrication, and a thin sac, or capsule, surrounding the joint and keeping the fluid in place. When this cartilage wears down, or degenerates, or the capsule is over-stretched, facet pain can be caused.
Common Causes of Facet Joint Pain
The facet joints play an important role in the movement and stabilization of the spine. But, like other joints in your body, they can become damaged by inflammation, age-related degeneration, wear and tear or a single incident. This can change their normal movement and create chronic and often debilitating low back pain.
- Osteoarthritis: When the cartilage layer between the bones of a facet joint is damaged or worn away, the bones can rub together and degenerative arthritis [osteoarthritis] occurs. This is the most common cause of facet joint pain.
- Disc height changes: When the height of the disc between your vertebrae changes, it changes the amount of weight your facets must support and the way that they move. This can be caused by degeneration, or wearing down, of the disc. In some cases, it can also be caused when the space between the vertebrae is increased, such as after receiving an articifical disc or total disc replacement.
- Injury: A fall or car accident can damage your facet joints. Backward bending, especially if the action is repetitive, can also cause facet pain. This is a common motion when playing tennis, for instance.
- Synovial Cysts: In some cases of arthritis or spondylolisthesis, cysts can develop within the facet joint. These cysts can place extra pressure on the facet joint capsule or the spinal cord, often causing pain that goes down the leg or makes walking painful.
- Infection: Although infection of the facet joint is uncommon, it is serious when present and can cause significant facet joint pain.
Facet joint pain has several causes, and it’s important to understand the cause of pain before it can be treated. If you suspect your pain is being caused by a problem with your facet joints, timely evaluation and treatment by an experienced spine specialist can help.