Osteoarthritis is a condition in which the cartilage that protects and cushions the joints breaks down over time. Eventually, the bones—formerly separated by the cartilage—rub against each other, resulting in damage to the tissue and underlying bone and causing painful joint symptoms.

Osteoarthritis is common in the joints of the spine, including the small facet joints and the large joints between the vertebrae.

The lower picture also shows flattened discs. This is a common part of aging in which the discs that cushion the bones of the spine lose fluid and can develop tiny cracks. When discs flatten, there is less space between the bones. This can make osteoarthritis worse and can also pinch the nerves that are near the spine.