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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
  1. Spine shape parameter definitions adapted from DIERS formetric III 4D Manual (Created 21.06.2010, Revision grade 5) and DIERS Optical Measurement of the Spine Information for the Assessment (Version 1, Created 04.08.2009)
  2. DL left sacral dimple, DM middle point between the left and right sacral dimples, DR right sacral dimple, ICT cervical-thoracic inflection point, ILS lumbar-sacral inflection point, ITL thoracic-lumbar inflection point, KA kyphotic apex, LA lordotic apex, RMS root mean square, SP sacral point, VP vertebral prominens