As people age, the structures that make up the backbone and neck and the lower back gradually develop wear and tear. These changes can include:

• Dehydrated disks. Disks act like cushions between the vertebrae of the spine. By the age of 40, most people's spinal disks begin drying out and shrinking. As the disks become smaller, there is more bone-on-bone contact between the vertebrae.
• Herniated disks. Cracks also appear on the exterior of the spinal disks. The soft interior of a disk can squeeze through these cracks. Sometimes, it presses on the spinal cord and nerve roots.
• Bone spurs. As the disks break down, the body may produce extra amounts of bone in a misguided effort to strengthen the spine. These bone spurs can sometimes pinch the spinal cord and nerve roots.
• Stiff ligaments. Ligaments are cords of tissue that connect bone to bone. Spinal ligaments can stiffen with age, making the neck less flexible.

Most people experience no symptoms. When symptoms do occur, they typically include pain and stiffness in the neck and lower back.

Sometimes, spondylosis results in a narrowing of the spinal canal within the bones of the spine (the vertebrae). The spinal canal is the space inside the vertebrae that the spinal cord and the nerve roots pass through to reach the rest of the body. If the spinal cord or nerve roots become pinched, you might experience:

• Tingling, numbness and weakness in the arms, hands, legs or feet
• Lack of coordination and difficulty walking
• Loss of bladder or bowel control