Deviation type · Pelvis
Posterior Pelvic Tilt
The pelvis rolls backward, flattening the lumbar curve and tucking the sacrum under.
What this describes
Posterior tilt is the opposite rotation: the PSIS rides up, the lumbar curve flattens, and the body tends to hang on the passive structures at the back of the hip rather than on muscle. It is far more common in people who sit for long stretches than people expect, and it is easy to mistake for "good posture" because it looks upright in a mirror. The reliable read is a wall test plus a seated observation of where the lumbar curve disappears.
Three-grade thresholds
| Grade | Threshold |
|---|---|
| Within range | Occiput, thoracic spine and sacrum all contact the wall; a hand cannot pass under the lumbar curve when standing tall. |
| Borderline | Sacrum contacts but the neck has to work to keep the occiput on the wall; lumbar curve flattens within 5 minutes of sitting. |
| Deviated | Sacrum loses wall contact, or the lumbar curve is flat in standing and stays flat when you are asked to arch. |
Self-screens for Posterior Pelvic Tilt on this site
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Wall Occiput-Thorax-Sacrum Check
Three contact points against a wall. Which ones reach it without effort, and which one is lost first, is the reading — and the flatter curve is the one people miss.