Each individual bone that makes up the vertebrae is called a vertebra. In between the vertebrae are flat, cushiony discs (known as intervertebral discs). When people get older, calcium deposits can form in the discs, making them less cushiony and thus, less able to absorb shocks. Calcium is a natural element that is very important for bone formation. Calcium deposits can result from chronic inflammation of the vertebrae, a condition known as spondylitis.

Inflammatory cells produce chemicals that damage the bone. This causes the bone to dissolve and weaken around the edge of each joint. The bone continuously tries to repair itself by producing new tissue but as this process continues the bones continue to weaken. Eventually, the inflammation stops and the body produces calcium to heal the damaged bone. For uncertain reasons, the calcium spreads to the disks between the vertebrae. This causes the vertebrae to fuse together (because the cushiony discs between them have hardened), a condition sometimes called bony ankylosis. There is no cure for this condition. It is treated with pain medication, physical therapy, and exercise.Calcified disks comes from the Latin word “calx” meaning “lime” and the Greek word "diskos" meaning "flat plate." Put the two words together and you have "lime flat plate."