Table 3.
Theoretical values for positional pelvis and spinal parameters related to pelvis incidence
| PI class | PI (°) | PTth (°) | LLth (°) |
| I | < 38 | 4 | PI + 18 |
| II | 38-47 | 8 | PI + 13 |
| III | 48-57 | 12 | PI + 9 |
| IV | 58-67 | 16 | PI + 6 |
| V | 68-77 | 20 | PI + 2 |
| VI | > 78 | 24 | PI - 5 |
PT: Pelvis tilt; LL: Lumbar lordosis; PTth: Theoretical PT; LLth: Theoretical LL. As examples, for PI measured to 40°, expected PT should be 8° and LL should be 53°; for PI measured to 52°, expected PT should be 12° and LL should be 61°; and for PI measured to 64°, expected PT should be 16° and LL should be 70°.