Homeostatic Imbalances of the Spinal Cord: Spinal Stenosis
Stenosis means "closing in" or "choking". Spinal stenosis describes a condition in which the nerves in the spinal canal are closed in, or compressed. The spinal canal is the hollow vertical hole formed by the bones of the spinal column. Anything that causes this bony hole to shrink can squeeze the nerves inside. This narrowing can irritate the nerve roots that branch out from the spinal cord, or it can squeeze and irritate the spinal cord itself. This may cause pain, numbness, or weakness, most often in the legs, feet and buttocks. As a result of many years of wear and tear on the parts of the spine, the tissues nearest the spinal cord sometimes press against the nerves. The actual narrowing of the spinal canal does not cause symptoms. Symptoms develop when the spinal cord or nerve roots are compressed. Spinal stenosis may affect the cervical, thoracic or lumbar spine. The most common area affected is the lumbar spine followed by the cervical spine. Although many people older than age 50 have some narrowing of the spinal canal, not all experience symptoms. This helps explain why lumbar spinal stenosis is a common cause of back problems in adults over 50 years old.
In the lumbar spine, the spinal canal usually has more than enough room for the spinal nerves. The canal is normally 17 to 18 millimeters around, slightly smaller than a penny. Spinal stenosis develops when the canal shrink to 12 millimeters or less. When the size drops below 10 millimeters, severe symptoms of lumbar spinal stenosis occur. There are many reasons why symptoms of spinal stenosis develop. Some of the more common reasons include congenital stenosis (being born with a small spinal canal), spinal degeneration, spinal instability and disc herniation.
Congenital stenosis happens when someone is born with a spinal canal that is narrower than normal. They may not feel problems early in life. However, having a narrow spinal canal puts them at risk for stenosis. Even a minor back
References: • American Association of Neurological Surgeons, "Your Aging Back: Understanding Lumbar Spinal Stenosis", 2007
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