text: definition of mild central canal stenosis? ralates to degerative disc changes in lower spine mild central canal stenosis means there is mild narrowing of the central canal of one or more vertebra(e).  the central canal contains the spinal cord down to about the 1st/2nd lumbar vertebrae.  below this level it contains the cauda equina, which consists of the remaining nerves extending down from the spinal cord.  it is much more important to understand what is causing the narrowing and, if possible, why the cause is present.