Medically reviewed by Dr. Kevin Lau, D.C., M.H.N. — Founder, ScolioLife®
Short answer: A scoliometer is a simple inclinometer that measures the Angle of Trunk Rotation (ATR) — the rotational asymmetry of the back when a person bends forward. Clinicians use it to screen for scoliosis; you can use one at home (including a smartphone scoliometer app) to monitor a curve between visits. The key to a useful reading is doing it the same way every time, in the Adam’s Forward Bend position.
The scoliometer is the single most practical tool for keeping an eye on scoliosis at home, because it’s quick, radiation-free, and repeatable. This guide explains what it is, how clinicians use it, and exactly how to take an accurate reading yourself.
A scoliometer (the original is the Bunnell scoliometer) is a small, curved inclinometer laid across the back. As the person bends forward, the spine’s rotation lifts one side of the rib cage or lower back; the scoliometer measures that tilt in degrees. That number is the Angle of Trunk Rotation (ATR).
It doesn’t measure the sideways curve directly (that’s the Cobb angle, measured from an X-ray — see ATR vs. the Cobb angle). Instead it measures the rotation that accompanies a scoliotic curve, which is why it works so well as a surface screening and monitoring tool.
The scoliometer is the standard tool for scoliosis screening — in clinics and in school screening programmes. A clinician asks the person to bend forward (the Adam’s Forward Bend Test) and runs the scoliometer down the spine to find the point of greatest rotation. A reading at or above roughly 7° is a widely used threshold to refer for further evaluation, often including an X-ray to measure the Cobb angle.
Crucially, the technique is simple enough to be reliable in non-specialist hands. Research has shown that smartphone scoliometer apps measure ATR comparably to a physical scoliometer, and that even parents can take reliable readings after brief instruction — which is what makes home use realistic.
A smartphone contains a tilt sensor (accelerometer), so a scoliometer app can measure ATR the same way a physical Bunnell does — by being laid flat across the back at the apex of the rotation. The advantages of the phone version are practical: it’s always with you, it can record and date each reading automatically, and it lets you see the trend over time rather than a single number. For monitoring, that history is the whole point.
This is the Adam’s Forward Bend Test. Have a second person take the reading where possible; consistency matters more than anything.
A small degree of asymmetry is common and not necessarily a concern. An ATR around 7° or more is a common referral threshold, and — just as importantly — any upward trend over time is worth reporting to your specialist. A scoliometer tells you when to seek imaging or review; it does not diagnose or measure curve severity on its own. Always follow the specific guidance your specialist has given you.
ScolioTrack turns your phone into a clinical-style scoliometer for measuring ATR — and stores each reading, dated, alongside posture photos and height so you can see the whole picture over time. For the full at-home routine, see how to monitor scoliosis at home.
For screening and monitoring, studies have found smartphone scoliometer apps measure the Angle of Trunk Rotation comparably to a physical Bunnell scoliometer. Accuracy depends on consistent technique.
Around 7° or more is a common referral threshold, and any rising trend is worth reporting. Use the threshold your specialist gave you, and flag changes rather than self-diagnosing.
No. It screens and monitors by measuring trunk rotation. Diagnosis and severity require a clinical assessment and the Cobb angle from an X-ray.
For a growing child, every 2–4 weeks (more often during a growth spurt) is common; monthly is usually enough for stable adult scoliosis. Follow your specialist’s advice.
It’s easier and more consistent with a helper taking the reading while the person bends forward, but a phone app makes solo readings more manageable.
Medical disclaimer: This article is for education, screening, and self-monitoring. It does not provide a diagnosis and is not a substitute for professional medical advice, examination, or imaging. Always consult a qualified healthcare provider about your individual condition. Results vary based on age, skeletal maturity, curve type, compliance, and individual factors.