This tube cannot expand if the spinal cord or nerves require more space. If anything begins to narrow the spinal canal, the risk of irritation and injury of the spinal cord or nerves increases. Spinal stenosis usually occurs in older people after years of wear and tear, or degeneration of the spine. All of these changes push into the spinal canal, making the tube of the spinal canal smaller. Eventually, there is not enough space in the spinal canal for the nerve to comfortably fit without causing too much pressure.
Stenosis can also develop from injuries, infections, or tumors.
Some people even have a narrow spinal canal from birth, an abnormality that leads to symptoms of stenosis. The narrowing of the spinal canal can lead to irritation of the nerves of the spine. This can cause pain and problems with the nerves not working properly. The lack of space can also cause the supply of blood and oxygen to the spinal cord to be reduced. When the spine needs more blood flow during increased activity, the blood vessels may not be able to swell to get more blood to the spine.