In the medical field, stenosis means the abnormal narrowing of a body channel. When combined with the word spinal, it defines a narrowing of the bone channel occupied by the spinal nerves or the spinal cord.
While the narrowing may occur at different parts of the spine, the symptoms of nerve compression are often similar. That is why specialists often will perform testing to determine the cause and location of the narrowing. In lumbar (low back) stenosis, the spinal nerve roots in the lower back become compressed and this can produce symptoms of sciatica—tingling, weakness or numbness that radiates from the low back and into the buttocks and legs—especially with activity.