The spine is the central bone that supports the neck and trunk, and the spinal canal is located within the spine, enclosed by a ring of vertebrae, intervertebral discs and ligaments that contain and protect the spinal cord, cauda equina and associated blood supplying arteries and veins. Any narrowing of the spinal canal, nerve root canal or intervertebral foramen that results in compression of the spinal cord or nerve roots, with consequent clinical manifestations, is known as spinal stenosis. Cervical and lumbar spinal stenosis are the most common, while thoracic spinal stenosis is relatively uncommon, but when it occurs, thoracic spinal stenosis can be extremely disabling.