Biomechanics · functional reading
Pelvic tilt (PT)
Pelvic tilt (PT) is the angle that measures the orientation of the pelvis in the sagittal plane. It increases when the pelvis tilts posteriorly and decreases when it tilts anteriorly: it is a positional parameter, which varies with posture.
Scientific basis
It is measured on a lateral X-ray: it is the angle between the vertical and the line connecting the center of the femoral heads to the midpoint of the sacral endplate. Together with sacral slope, it satisfies the relationship pelvic incidence = pelvic tilt + sacral slope. Since pelvic incidence is fixed for each person, when pelvic tilt increases, sacral slope decreases by the same amount.
When moving from standing to sitting, pelvic tilt increases markedly: this is the numerical expression of the posterior tilt of the pelvis when sitting. An increase in pelvic tilt is also one of the compensatory mechanisms of sagittal balance. In English, the parameter is called pelvic tilt (PT).
Blue Portance / SBNFA™ reading
In the SBNFA™ reading, pelvic tilt (PT) is a marker of the sagittal orientation of the pelvis. Its range of variation is conditioned by pelvic incidence, which is specific to each person. There is no ideal value to reach: pelvic tilt describes what the position engages, within the limits set by morphology.
Contribution to the analysis of sitting
Seating analysis does not measure pelvic tilt (PT), which is a radiological parameter. It observes the orientation of the pelvis and its variations, which this angle makes it possible to quantify on imaging.
Not to be confused with
Pelvic incidence, a fixed morphological parameter that does not vary with posture; sacral slope, the other positional parameter, which varies in the opposite direction; anterior and posterior pelvic tilt, orientations or movements of the pelvis that pelvic tilt (PT) measures.
Related terms
Anterior pelvic tilt · Pelvic incidence · Pelvic mobility · Sacral slope · Posterior pelvic tilt
Sources and scope
- Le Huec et al. (2011): pelvic parameters, origin and significance (European Spine Journal)
- Kouyoumdjian (2023): involvement of the hip-spine relationship in hip arthroplasty surgery (Revue de chirurgie orthopédique et traumatologique) (in French)
- Barrey et al. (2013): compensatory mechanisms of spinal sagittal balance (European Spine Journal)
An established radiological parameter. Values depend on the person and the position; they cannot be inferred from external observation.
Further reading
- Learn more — Article: Spinal Profiles and Seated Posture: Restoring Your Natural Balance Rather Than Correcting It
- Go further — Expert guide: How Does Sitting Load Fascia and Other Tissues?
