Seated flexion test

The seated flexion test is a palpation-based assessment of sacral motion at the sacroiliac (SI) joint during forward trunk flexion. The examiner tracks both posterior superior iliac spines (PSIS) as the seated patient bends forward. If one PSIS rises first or travels further, the test is positive and suggests restricted sacral motion on that side.

Osteopathic physicians, physical therapists, and chiropractors use it as one part of a wider SI joint assessment, never as a standalone diagnosis. This page covers the procedure, how to read the result, and how the test differs from the standing flexion test.

Completed assessments can live in Pabau digital forms, part of the practice management platform we build, so each finding stays with the patient record.

Key takeaways

The seated flexion test checks sacral motion with the legs held still.

A positive result is a motion finding, not a standalone diagnosis.

Evidence on reliability is limited, so pair results with other SI joint tests.

Pabau digital forms can keep each assessment in the patient’s record.

What the seated flexion test assesses

The seated flexion test assesses sacral motion during forward trunk flexion. It is generally taught with the patient seated so that the innominate bones move less, which lets the examiner focus on the sacrum.

Clinicians typically reach for it when they suspect sacroiliac joint dysfunction, pelvic asymmetry, or low back pain that may come from the SI joint. The method is described in Physiopedia’s seated flexion test entry and in osteopathic teaching texts.

The test relies on three landmarks:

• The posterior superior iliac spines (PSIS), the bony points on the back of the pelvis.
• The sacrum, which sits between the two innominate bones.
• The innominate bones, also called the ilium, which the seated position helps keep largely still.

Knowing these landmarks well makes the movement easier to read. If you can’t find both PSIS points with confidence, the result will be unreliable, so take time to palpate before you start.

Step-by-step procedure

To perform the test, seat the patient on a treatment table with the legs supported and the feet resting flat. Then follow these steps:

1. Stand behind the patient and place your thumbs on both PSIS at the same height.
2. Ask the patient to flex forward slowly from the trunk, keeping the legs still.
3. Watch which PSIS rises first, and whether one side moves further superiorly or anteriorly than the other.
4. Return the patient upright and repeat the movement to confirm the finding.

Record which side moved first and how far, not only whether the test was positive. Stop the assessment if the patient reports new or severe pain, and follow your local clinical protocols.

Common mistake: rushing the trunk movement makes it hard to see which PSIS leads. Move at a steady pace so each side is easy to compare.

Here’s the whole test on one page, including how to read what you see.

What a positive result means

A positive seated flexion test indicates a possible motion asymmetry at the SI joint, not a confirmed diagnosis. Many practitioners read the side where the PSIS rises first as the side of sacral restriction. That link comes mainly from manual therapy teaching rather than strong trial data.

Before acting on a positive result, check it against the rest of the picture:

• The patient’s relevant history, including any recent injury
• Other SI joint tests, such as the Gaenslen test or the Gillet test
• Whether the patient’s usual pain reproduces with the movement
• Your confidence in palpating both PSIS points

Reliability evidence for this test is limited and debated, so a single positive result shouldn’t drive treatment decisions on its own. Pain provocation tests, such as the thigh thrust test, tend to show better reliability, so many clinicians add one to the exam.

Seated flexion test vs standing flexion test

The seated flexion test isolates sacral motion, while the standing flexion test is generally taught as a way to assess innominate motion. Both use the PSIS as their main landmark, so the difference lies mainly in the starting position.

Many clinicians run both tests in the same assessment, since comparing the two findings can help narrow down which structure is involved. Treat that comparison as a clinical judgment, not a fixed rule.

Who is this template helpful for?

This template suits practitioners who assess the sacroiliac joint as part of a wider examination. It is most relevant in three settings:

• Osteopathic practices running osteopathic manipulative medicine (OMM) assessments
• Physical therapy practices screening for pelvic or low back pain
• Chiropractic offices documenting spinal and pelvic findings

Osteopathy teams can keep this test next to their other notes in osteopathy practice software, so findings stay linked to each treatment plan. The American Osteopathic Association has also shared research on how reliable the standing and sitting flexion tests are.

Physical therapy practices can file the result with each plan of care in an EMR built for physical therapists.

Chiropractic offices often need a repeatable way to record pelvic findings across visits. Practices that want a home for these notes can look at chiropractic software built around that routine.

Benefits of using this template

A shared form keeps findings consistent between practitioners and between visits. That consistency makes follow-up comparisons far easier.

• Every practitioner records the same landmarks in the same order
• Results sit alongside the standing flexion test comparison
• Next steps are written down while the patient is still in the room

How Pabau keeps SI joint findings comparable across visits

On paper, this test is hard to track over time. A sheet filed after one visit rarely sits next to the sheet from the visit before, so nobody checks which PSIS led last time.

In Pabau, the template becomes a digital form attached to the patient’s file. Each completed assessment is stored in client records in Pabau, beside earlier notes, treatment plans, and other SI joint tests.

If your team writes long clinical notes, Pabau Scribe, our AI scribe, can turn dictated findings into structured documentation and cut write-up time. Clinicians still review every note before it is saved.

The payoff comes at the next appointment. You open the patient’s file, see last visit’s finding beside today’s, and know whether treatment changed the motion.

See how Pabau keeps assessments in the patient record

Book a demo to see how Pabau digital forms and client records store clinical assessments alongside the rest of the patient history.

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Conclusion

Treat the seated flexion test as one motion finding, read alongside provocation tests and the patient’s history. On its own, it shouldn’t decide treatment.

Its value grows with repetition. Run it the same way at every visit, and write down which side led and how far. Then you can tell whether treatment changed the motion or the reading simply drifted between examiners.

Book a demo to see how Pabau keeps each SI joint assessment ready to compare at the next visit.

Continue your research

Need an intake process before the assessment? Chiropractic intake form template is a starting point for collecting history before a spinal exam.

Want patients to show you where it hurts? Back pain location charts let patients mark their pain before you examine the SI joint.

Checking pelvic posture as well? Anterior pelvic tilt covers how forward pelvic rotation is assessed.

Running an osteopathic practice? Osteopathy practice management software looks at software built for osteopathic practices.

Frequently asked questions