Vertebrae Degeneration, Stages of Prolapsed Disc; Natural cast model illustrates degenerative changes to the vertebrae and intervertebral discs of the lumbar spine in five progressively serious degrees• From healthy disc and vertebrae all the way to very severe degeneration and bony constriction of the left intervertebral foramen with pressure on the spinal nerve root L5• 9" length mounted on base• Germany