Spinal stenosis is an abnormal narrowing (stenosis) of the spinal canal that may occur in any of the regions of the spine. This narrowing causes a restriction to the spinal canal, resulting in a neurological deficit. Symptoms include pain, numbness, paraesthesia, and loss of motor control. The location of the stenosis determines which area of the body is affected. With spinal stenosis, the spinal canal is narrowed at the vertebral canal, which is a foramen between the vertebrae where the spinal cord (in the cervical or thoracic spine) or nerve roots (in the lumbar spine) pass through. There are several types of spinal stenosis, with lumbar stenosis and cervical stenosis being the most frequent. While lumbar spinal stenosis is more common, cervical spinal stenosis is more dangerous because it involves compression of the spinal cord whereas the lumbar spinal stenosis involves compression of the cauda equina.
The most common forms are cervical spinal stenosis, at the level of the neck, and lumbar spinal stenosis, at the level of the lower back. Thoracic spinal stenosis, at the level of the mid-back, is much less common.
In lumbar stenosis, the spinal nerve roots in the lower back are compressed which can lead to symptoms of sciatica (tingling, weakness, or numbness that radiates from the low back and into the buttocks and legs).
Cervical spinal stenosis can be far more dangerous by compressing the spinal cord. Cervical canal stenosis may lead to serious symptoms such as major body weakness and paralysis. Such severe spinal stenosis symptoms are virtually absent in lumbar stenosis, however, as the spinal cord terminates at the top end of the adult lumbar spine, with only nerve roots (cauda equina) continuing further down. Cervical spinal stenosis is a condition involving narrowing of the spinal canal at the level of the neck. It is frequently due to chronic degeneration, but may also be congenital or traumatic. Treatment frequently is surgical.
Signs and symptoms
Standing discomfort (94%)
Bilateral symptoms (68%)
Discomfort above and below knee (78%)
Buttock / Thigh only (15%)
Below the knee (7%)
Pinched nerve, causing numbness.
Intermittent neurogenic claudication characterized by lower limb numbness, weakness, diffuse or radicular leg pain associated with paresthesis (bilaterally),weakness heaviness in buttocks radiating into lower extremities with walking or prolonged standing. Symptoms occur with extension of spine and are relieved with spine flexion. Minimal to zero symptoms when seated or supine.
A human vertebral column
Radiculopathy (with or without radicular pain)  neurologic condition – nerve root dysfunction causes objective signs such as weakness, loss of sensation and of reflex.
Cauda equina syndrome  Lower extremity pain, weakness, numbness that may involve perineum and buttocks, associated with bladder and bowel dysfunction.
Unexplained weight loss
Severe pain upon lying down
Recent trauma with suspicious fracture
Presence of severe or progressive neurologic deficit 
Lower back pain  due to degenerative disc or joint changes 
Narrowing of spinal canal, nerve root canal or intervertebral Canal Stenosis: Start with nonsurgical therapy. Cleveland ral foramina 
Aging: All the factors below may cause the spaces in the spine to narrow,
Body’s ligaments can thicken (ligamentum flavum)
Bone spurs develop on the bone and into the spinal canal
Intervertebral discs may bulge or herniate into the canal
Facet joints break down
Compression fractures of the spine, which are common in osteoporosis
Cysts form on the facet joints causing compression of the spinal sack of nerves (thecal sac)
Arthritis: Two types,
Rheumatoid arthritis—much less common cause of spinal problems
Spinal canal is too small at birth
Structural deformities of the vertebrae may cause narrowing of the spinal canal
Instability of the spine, or spondylolisthesis:
A vertebra slips forward on another
Accidents and injuries may dislocate the spine and the spinal canal or cause burst fractures that yield fragments of bone that go through the canal
Tumors of the spine:
Irregular growths of soft tissue will cause inflammation
Growth of tissue into the canal pressing on nerves, the sac of nerves, or the spinal cord.