The spine is made of a column of bones called vertebrae, and extends from the base of the skull to the pelvis. The vertebrae protect the spinal cord, which runs within the vertebral column and sends out nerve roots between the vertebrae. Between the bony bodies of each vertebra is a gelatinous ring of tissue, called a disc. The discs absorb shock and cushion motion between the vertebral bones.
As the body ages, chemical and structural changes occur within the disc, causing it to weaken and lose some of its protective properties. Degenerative disc disease isn’t actually a disease, but rather a normal side effect of aging. As the disc ages, it dries out and loses pliability, height, and integrity. Vertebrae stack more closely together on the thinning discs provide less cushioning and shock absorption. Degenerative discs may crack and bulge, putting pressure on nerve roots.