Table 1 Radiographic zoning of disc herniation
Zone | Location | Range of distance |
|---|---|---|
Zone 1 | High-grade up | Above the lower half of the inferior pedicle |
Zone 2 | Low-grade up | Between the upper margin of disc space and the upper half of the inferior pedicle, |
Zone 3 | Disc level | From the inferior margin of upper vertebral body to the superior margin of lower vertebral body |
Zone 4 | Low-grade down | From the superior margin of lower vertebral body to the center of lower pedicle |
Zone 5 | High-grade down | From the center to the inferior margin of lower pedicle |