Facet joint arthritis, also known as facet arthropathy, occurs due to arthritic changes in the facet joints at the back of the spine, causing back pain, instability of the spine, or back muscle spasms.
The joints involves in aiding movement and providing protection for the bones of the spine are the intervertebral discs and the facet joints. The intervertebral discs are located between the vertebral bones at the front of the spine. The discs are located between the vertebral bodies, and they have a flexible nucleus that helps the structure to provide cushion and shock absorption. Degenerative disc disease may occur in these discs when the outer layers of the disc fray or tear, or the volume of gel-like fluid in the core of the disc begins to dry out. Some back disorders associated with anatomical changes to the discs include degenerative disc disease, bulging discs, herniated discs, and sciatica.
Located behind the vertebral body, is a vertebral arch. The lamina is located on the vertebral arch, as well 7 processes that join the segments of the spine together, allow for attachments of ribs, muscles and ligaments, and provide protection of the spine. From the vertebral arch. One spinous process projects towards the surface of our back, and two transverse processes project laterally. Two processes project upwards and two project downwards to joint with the processes of the vertebral bones above them. The processes from the vertebral arch that project upwards are known as the superior articular processes, and the two processes that project downwards are known as the inferior articular processes. Located at the ends of each process is a is a flattened section called a facet. The facet joint includes the facets, smooth cartilage between the facets, and the capsule that holds the joint together. Just like with the other synovial joints of the body, the facets may undergo degenerative changes associated with the aging process or injury. Arthritic changes to the facet joints are known as facet joint arthritis, spondylosis, and facet arthropathy.
Facet arthropathy can cause back pain in several ways. First, we may experience back pain as a direct result of the changes to the facet joints. The facet joints are supplied with pain-sensitive nerve fibers that notify the brain when pathological changes to these important structures occur. Also, changes to the facet joints may cause the facets holding the spine together to pull away from each other, causing instability of the spine. This instability could affect the other soft tissues of the spine, including the ligaments, tendons, and nerve roots.
As a result of facet arthropathy, the worn out cartilage separating the facet faces no longer provides protection against friction, as the faces begin to run together. This friction caused by direct contact between the facets causes bone spurs and enlargement of the joints. Typically, this wasting away of the cartilage between the facet faces is due to osteoarthritis, which involves wear and tear injuries rather than systemic disease such as rheumatoid arthritis. When inflammation occurs in the facet joints, the spine itself, along with all its soft tissues and nerve roots of the spinal cord, may become vulnerable or unstable. To protect against this instability, the muscles compensate by contracting, to reduce mobility to this area. When these muscles remain contracted, the condition may be known as a muscle spasm or chronic muscle tension.