There may be a genetic component that predisposes some people to more rapid wear. Injury may also accelerate and sometimes cause the development of the degenerative changes.
How Cervical Discs Can Degenerate
Normally, there are six gel-like cervical discs (one between each of the cervical spine’s vertebrae) that absorb shock and prevent vertebral bones from rubbing against each other while the neck moves.
Each disc is comprised of a tough but flexible outer layer of woven cartilage strands, called the annulus fibrosus. Sealed inside the annulus fibrosus is a soft interior filled with a mucoprotein gel called the nucleus pulposus. The nucleus gives the disc its shock absorption property.
In children, the discs are about 85% water. The discs begin to naturally lose hydration during the aging process. Some estimates have the disc’s water content typically falling to 70% by age 70,1 but in some people the disc can lose hydration much more quickly.
As the disc loses hydration, it offers less cushioning and becomes more prone to cracks and tears. The disc is not able to truly repair itself because it does not have a direct blood supply (instead getting nutrients and metabolites via diffusion with adjacent vertebrae through the cartilaginous endplates). As such, a tear in the disc either will not heal or will develop weaker scar tissue that has potential to break again.