Stenosis refers to a narrowing of the spinal canal and openings for the spinal nerves. Changes in the bones, soft tissues, and joints contribute to stenosis.

For example, the broad band of ligament that runs down the spine called the ligamentum flavum (LF) starts to thicken. It can even get pinched between the vertebral bones causing additional pain.

The vertebral bodies start to weaken and compress. The discs thin out and lose their soft flexibility. The vertebrae and joints start to move closer together. Bone spurs form around the joints. The joints may become misshapen and lose their normal ability to slide and glide. The joints may no longer fit together and move smoothly. This adds to the problem.

Some people are born with a narrow spinal canal. This is not a problem during the younger years. But with the changes described here, the spinal opening is gradually closed off. Pressure on the spinal cord or spinal nerves causes back and/or leg pain.