Facet joints are small joints which connect the vertebrae (spinal bones) together and allow movements of the back. These small facet joints also have cartilage same as seen in other joints. When due to any reason there is any inflammation or degenerative changes in the facet joint or cartilage it causes facet joint arthritis. Low back pain due to facet joint arthritis is the main symptom. Commonly facet joint suffers from osteoarthritis which causes severe low back pain and restricts the movement of the back (forward bending and backward movement and sideways movements).