Mounted together on a hardwood base are four sets of 4th and 5th lumbar vertebrae (L4 and L5) with their intervertebral disk.

The first set typifies the normal healthy condition of bone and disc. The three remaining pairs exhibit progressive stages in pathological degeneration of the lower spine,herniated disc and facet syndrome,thinning disc and arthritic bone spurring ? advanced bone degeneration with fusion (spondylosis).

Overall dimensions: 16x3x4 inches (41x8x10 cm)