1. Canal stenosis

2. The canal and foramen are formed (Figure 1) by bony structures (vertebral body, facets, pedicles) as well as soft tissue structures (ligamentum flavum, facet capsules, intervertebral disc annulus). As we age, degenerative changes occur in our spine causing narrowing of the central spinal canal area, and/or the area where the nerve roots exit the spinal canal (foramina). One of these degenerative changes is the formation of extra bony growths called osteophytes. Additionally, the large connective "band" (ligamentum flavum) which runs along the inside the spinal canal can become coarse and thickened also causing narrowing of the central canal space.