what causes the discs to dry up and crack or fragment? i have had a discogram from L4-5 TO L1-2 and they all looked the same with the dye streaking through the discs. i had proper spacing in my vertabre when the discogram, mylogram,and mri while laying down . the last neurologist made the comment of he wondered how many more of my discs were bad since the range of discogram didn't go any further up. the neurologists (3)just didn't offer any help . i have been exposed to depleted uranium ,chromium,barium,cadmium,lead which i have told the doc's but they don't say anything about the effects of exposure .the only other problem besides my back is my finger and toe nails are thin and spliting.