Several factors can contribute to the narrowing of the spinal canal, leading to spinal stenosis. Normally, the vertebral canal provides enough room for the spinal cord, cauda equina, and the exiting nerves. However, aging and age-related changes in the spine, injury, other diseases, or inherited conditions can cause narrowing of the spaces.

Aging and age-related changes in the spine happen over a period of time and slowly cause loss of the normal structure of the spine. They are the most common causes of spinal stenosis. As people age, the ligaments that keep the vertebrae of the spine in place may thicken and calcify (harden from deposits of calcium salts). Bones and joints may also enlarge. When surfaces of the bone begin to project out from the body, these projections are called osteophytes (bone spurs). For example:

Arthritis is also a common cause of spinal stenosis. Two forms of arthritis that may affect the spine are osteoarthritis and rheumatoid arthritis.

The following conditions also may cause spinal stenosis:

Some people are born with a condition that can cause spinal stenosis. These conditions cause the spinal canal to narrow, leading to spinal stenosis. For example:

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Spinal Stenosis Symptoms, Causes, & Risk Factors | NIAMS