Fig. 3
A-B-C degenerative changes. (a) A-changes. The degenerative process usually starts within the nucleous pulposus representing A-changes. (b) B-changes. The abnormalities extend to the disc, annulus fibrosus, end plates and bone marrow of the adjacent vertebral bodies. (c) C-changes. The advance degeneration may eventually involve distant structures and lead to facet joint osteoarthrosis, ligamentum flavum hypertrophy (not shown) and spinal canal stenosis (not shown)