Intermittent neurogenic claudication characterized by lower limb numbness, weakness, diffuse or radicular leg pain associated with paresthesia (bilaterally), weakness and/or 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. 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. Lower back pain due to degenerative disc or joint changes. Causes
Aging
Any of the factors below may cause the spaces in the spine to narrow. Spinal ligaments can thicken (ligamenta flava)
Bone spurs develop on the bone and into the spinal canal or foraminal openings
Intervertebral discs may bulge or herniate into the canal or foraminal openings
Degenerative disc disease causes narrowing of the spaces. Facet joints break down
Facet joints may hypertrophy
Compression fractures of the spine, which are common in osteoporosis
Synovial cysts form on the facet joints causing compression of the spinal sac of nerves (thecal sac)

Arthritis
Osteoarthritis
Rheumatoid arthritis—much less common cause of spinal problems

Congenital
Spinal canal is too small at birth
Structural deformities of the vertebrae may cause narrowing of the spinal canal. Instability of the spine
A vertebra slips forward on another (spondylolisthesis)

Trauma
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.
Patients with cervical myelopathy caused by narrowing of the spinal canal are at higher risks of acute spinal cord injury if involved in accidents. Tumors
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. Diagnosis
The diagnosis of spinal stenosis involves a complete evaluation of the spine. The process usually begins with a medical history and physical examination. X-ray and MRI scans are typically used to determine the extent and location of the nerve compression. Medical history
The medical history is the most important aspect of the examination as it will tell the physician about subjective symptoms, possible causes for spinal stenosis, and other possible causes of back pain. Physical examination
The physical examination of a patient with spinal stenosis will give the physician information about exactly where nerve compression is occurring. Some important factors that should be investigated are any areas of sensory abnormalities, numbness, irregular reflexes, and any muscular weakness. MRI
MRI has become the most frequently used study to diagnose spinal stenosis. The MRI uses electromagnetic signals to produce images of the spine. MRIs are helpful because they show more structures, including nerves, muscles, and ligaments, than seen on X-rays or CT scans. MRIs are helpful at showing exactly what is causing spinal nerve compression. Myelography
In CT myelography, spinal tap is performed in the low back with dye injected into the spinal fluid. X-rays are performed followed by a CT scan of the spine to help see narrowing of the spinal canal.