Table 1 Spine shape parameters output by the DIERS formetric 4D instrument and their definitions
From: Appraisal of the DIERS method for calculating postural measurements: an observational study
| Spine shape parameters by subgroup | Definition |
|---|---|
| Localization and distance | |
| Trunk length VP-DM, mm | The distance from VP to DM |
| Trunk length VP-SP, mm | The distance from VP to the SP |
| Trunk length VP-SP, % | The distance of VP-SP expressed as a percentage of VP-DM |
| Dimple distance, mm | The distance from DL to DR |
| Dimple distance, % | The distance of DL to DR expressed as a percentage of VP-DM |
| Trunk and pelvis imbalances | |
| Trunk inclination VP-DM, ° | The angle between the line connecting VP-DM and an external vertical line |
| Trunk inclination VP-DM, mm | The distance between VP and the connecting external vertical line |
| Trunk imbalance VP-DM, ° | The angle between the line connecting VP-DM and a vertical line through VP |
| Trunk imbalance VP-DM, mm | The lateral distance between VP and DM |
| Pelvic tilt DL-DR, ° | The angle between the line connecting DL and DR and an external horizontal line |
| Pelvic tilt DL-DR, mm | The difference in height between DL and DR |
| Pelvic torsion DL-DR, ° | The torsion of the surface normals of DL and DR |
| Pelvic inclination dimples, ° | The mean vertical components of the surface normals at DL and DR |
| Rotation correction pelvis, ° | In the frontal plane the angle of rotation of DR in the frontal plane in relation to DL |
| Spinal reference points | |
| Inflection point ICT, mm | The point of maximum positive surface inclination above the KA |
| Kyphotic apex, mm | The location of the posterior apex of the sagittal profile |
| Inflection point ITL, mm | The point of maximum negative surface inclination between the KA and the LA |
| Lordotic apex, mm | The location of the frontal apex of the sagittal profile in the lower region |
| Inflection point ILS, mm | The point of maximum positive surface inclination in the region between the LA and the sacrum |
| Fleche cervicale, mm | The horizontal distance between the cervical apex and the tangent through the KA |
| Fleche lombaire, mm | The horizontal distance between the LA and the tangent through the KA |
| Fleche cervicale VP, mm | The horizontal distance between the VP and the KA |
| Spinal curve measurements | |
| Kyphotic angle ICT-ITL, ° | The angle between the surface tangents from the ICT and ITL |
| Kyphotic angle VP-ITL, ° | The angle between the surface tangents from VP and ITL |
| Kyphotic angle VP-T12, ° | The angle between the surface tangents on VP and the location of the calculated T12 |
| Lordotic angle ITL-ILS, ° | The angle between the surface tangents from ITL and ILS |
| Lordotic angle ITL-DM, ° | The angle between the surface tangents from ITL and DM |
| Lordotic angle T12-DM, ° | The angle between the surface tangents from T12 and DM |
| Pelvic inclination, ° | The angle of the vertical surface normals from the horizontal of DM |
| Spinal deviation | |
| Surface rotation RMS, ° | The RMS of the horizontal components of the surface normals on the symmetry line |
| Surface rotation, ° | The maximum value of the horizontal components of the surface normals on the symmetry line |
| Surface rotation right ° | The maximum value of the horizontal components of the surface normals on the symmetry line to the right |
| Surface rotation left, ° | The maximum value of the horizontal components of the surface normals on the symmetry line to the left |
| Surface rotation amplitude, ° | The maximal spinal torsion calculated from the maximal rotation to the right and the left |
| Trunk torsion, ° | The maximal value of the horizontal components on VP compared to the horizontal components of the symmetry line on DM |
| Lateral deviation RMS, mm | The RMS deviation of the midline of the spine from the direct connection of VP-DM in the frontal plane |
| Lateral deviation, mm | The maximum deviation of the midline of the spine from the direct connection of VP-DM in the frontal plane |
| Lateral deviation right, mm | The maximum deviation of the midline of the spine from the VP-DM line to the right |
| Lateral deviation left, mm | The maximum deviation of the midline of the spine from the VP-DM line to the left |
| Lateral deviation amplitude, mm | The sum of the maximum deviation of the right and the left lateral deviation values |