Figure 3

Representative discs from the porcine lumbar spines of different age. (A) Younger disc (Grade I; Boos N. et al), (B) Mature Disc (Grade III), (C) Older Disc (Grade IV), In the older disc, the gelatinous nucleus had been replaced by fibrous material or disappeared. There was a loss of annular-nuclear demarcation. (Macroscopic grading of age-related disc alterations according to Thompson et al.1990)