Spinal stenosis is defined as narrowing of the spinal canal (the canal in the center of the spine), lateral recess (the narrowing of the tunnels where the nerve roots exit the central spinal canal), or intervertebral foramina (holes in the vertebrae which nerve roots exit). It can occur at any age and is typically due to the degeneration and enlargement of the facet joints (small joints between upper and lower vertebrae), the protrusion or herniation of the intervertebral discs and/or ligamentum flavum hypertrophy (a strong ligament that connects the vertebrae together). The narrowing of the canals puts pressure on the neural elements of the spine, including the spinal cord and nerve roots. Pressure on the upper part of the spine (neck area) usually produces pain, numbness, tingling or weakness in the shoulders, or arms. Pressure on the lower part of the spine (low back area) usually causes similar symptoms in the legs.
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