HI, thanks for using healthcare magic The spine is divided into the cervical (by the neck), thoracic (chest) ,lumbar (lower back) vertebra and the sacrum. There are five lumbar vertebra from L1 to L5. S1 refers to the sacrum In between the vertebra (bones in the back), there are discs that help as shock absorbers and protect some of the nerves coming from the spine. The nerves in the back leave the spinal cord and travel to the different parts of the body where they help with sensations. They travel through different openings in the back, one of these the neuroforamen. The central canal contains the spinal cord Lumbar spondylosis- degeneration/arthritis of the vertebra in the lower back Moderate L3 to L4, L5 to S1 central canal stenosis- the central canal containing the spinal cord is narrowed in these areas Moderate L5 to S1 neuroforaminal narrowing- this space, where nerves from coming from the spinal cord travel, is narrow in these areas Treatment would depend on the degree of impairment and pain. It may consist of physiotherapy and pain medication. If this is not helpful, then surgery may be considered. I hope this helps