Degenerative disc disease is the loss of cushioning ability in a disc in the back or neck. Discs, rubbery cushions between the bones in the spine (vertebrae), absorb shock when you walk or run.
Discs are made of soft cartilage in the center surrounded by a layer of tough cartilage. Cartilage cushions and protects joints and prevents them from rubbing against each other. The softer cartilage in discs is like jelly.
Normal wear and tear as you age breaks down the discs (makes them degenerate). This can cause back pain and stiffness. Degenerative disc disease is most common in the lower back or neck.