Degenerative Disk Disease
Disks lie between the spinal bones (vertebra). They serve as shock absorbers. This protects the spine and helps it stay flexible. Degenerative disk disease is wear and tear on these disks. This wear and tear causes pain and other symptoms. Some degeneration is normal as you age. Not all degeneration will result in symptoms of this disease.
The disk loses fluid and is not as resilient as normal. The fibrous tissue, which holds the disk material in place, may suffer small tears. These tears lead to further damage. There is some evidence that genetics may play a part for some people.