"Stenosis" is the medical term for "narrowing". Spinal stenosis means the narrowing of the channel in the spine (spinal canal) containing the spinal cord and nerves as they travel to your arms and legs from the brain. This spinal canal is a completely enclosed passageway surrounded by bones and joints of the spine (like a "train tunnel") protecting the spinal cord and nerves within from harm (similar to your skull protecting the brain within).
Unfortunately, narrowing of this spinal canal will compress the spinal cord and nerves within it too. Spinal stenosis can be a normal process as our spine (discs bulging and joints enlarging) age naturally or abnormal in cases of fractures, dislocations, infection, cancer in the spine which are less common.
Regardless of the cause, when the narrowing exceeds 50% of the spinal canal volume, patients will begin to experience neurological deficits (nerve pain, numbness, weakness) the severity of which will only be confirmed by an MRI scan. In severe cases when the spinal canal continues to narrow further with time, paralysis will eventually result in time. At this stage, unfortunately, surgery is the only treatment that can prevent further neurological progression.
