Disc herniations in the young and end-plate vascularity.

The objective of this study was to determine the nature of the persistence of remnants of the original nutritive vascular canals within the vertebral body and correlate their existence with end-plate "weak spots." The body-disc region of 20 lumbar vertebrae between the ages of birth and 22 years was examined histologically to study the vascularity of the end-plate cartilage and its fate at the end of vertebral growth. Observations indicate a regression of the vascular canals in the end-plate commencing in the first decade, with "scars" left by these canals visible as nodular areas. By the beginning of the third decade, herniation of the disc material into the weak spots was observed. It is apparent that these weak spots represent a route for the early formation of intrabody nuclear herniations at this age (Schmorl's nodes).