| Classification | Description | Notes |
| Zone 1 | Fracture through sacral ala | |
| Zone 2 | Involves one or more formaina | Does not impinge upon central canal |
| Zone 3 | Involves primarily the central canal | Includes H- or U-type fractures |
Reference:
Denis, F., et al. (1988). “Sacral fractures: an important problem. Retrospective analysis of 236 cases.” Clin Orthop Relat Res 227: 67-81.