A scoliometer is used during the Adam’s Forward Bend Test. The person bends forward, the instrument is laid flat across the back, and the highest Angle of Trunk Rotation (ATR) reading is recorded. Technique matters more than the tool.
Most inconsistent scoliometer readings come from posture and positioning, not from the instrument. A back that is not level, a phone held at an angle, or a different tester each time will move the number by several degrees on its own. This guide walks through the screening step by step, then covers the mistakes that most often distort a reading.
What you need
- A physical scoliometer, or the Scoliometer App on a smartphone.
- A level, firm floor — not a bed, mat or sloping surface.
- Good lighting and a clear view of the back. Remove or lift clothing so the spine is visible.
- A second person to take the reading. Self-measurement is unreliable for this test.
- Somewhere to record the result — date, region and reading.
Step by step: performing the forward bend test
- Stand the person straight, feet together. Knees straight, weight even on both feet, shoes off. Uneven weight tilts the pelvis and skews everything that follows.
- Have them bend forward from the hips. Arms hang loosely, palms together, head and neck relaxed. They bend until the back is roughly horizontal — not into a full toe-touch, which rounds the spine and flattens the asymmetry you are trying to see.
- Stand behind them, at eye level with the back. Sit or crouch so you are looking along the back rather than down at it.
- Place the scoliometer flat across the back, perpendicular to the spine, with its centre on the spinous processes. If you are using the app, rest the phone flat on the back in the same orientation, without pressing.
- Move slowly down the back — upper back (thoracic), mid back (thoracolumbar), then lower back (lumbar). Pause at each region and let the reading settle.
- Record the highest reading and where it occurred. A single peak value is what screening guidelines refer to. Note the region: “7° thoracic, right” is far more useful later than “7°”.
Getting a reading you can compare over time
A single number tells you less than a series of numbers taken the same way. To make readings comparable:
- Keep the same tester. Between-tester variation is the largest single source of inconsistency.
- Keep the same setup — same floor, same bend depth, same phone, ideally no phone case.
- Measure at the same time of day. Posture and height vary slightly through the day.
- Repeat the measurement two or three times and use the highest consistent value, rather than a single pass.
- Log every reading with a date. Trend matters as much as any individual result.
Common mistakes and what they do to the reading
| Mistake | Effect on the reading |
|---|---|
| Bending too far (full toe-touch) | Flattens the rib prominence — reads lower than it should |
| Not bending far enough | Rotation is not yet exposed — reads lower |
| Feet apart, or weight on one leg | Tilts the pelvis — can add several degrees of false asymmetry |
| Instrument not perpendicular to the spine | Measures the wrong axis — unpredictable error |
| Pressing the phone into the back | Compresses soft tissue — usually reads lower |
| Thick or uneven phone case | Tilts the device — a consistent offset in every reading |
| Measuring on a soft or sloping surface | Removes the level reference — unreliable |
| Different tester each time | Makes the trend uninterpretable |
What the number means
Screening thresholds in common use: below 5° is generally considered low, 5°–6° deserves attention (and is the usual referral point for overweight children, in whom curves are more easily missed), and 7° or more is the commonly accepted threshold for referral to a healthcare professional. An increase of around 5° between measurements warrants review even if the absolute value still looks modest. For a fuller explanation, see what a normal scoliometer reading is.
When to seek professional review
Book an assessment if a reading reaches the referral threshold, if readings are rising across measurements, or if you also notice uneven shoulders, a prominent shoulder blade, an uneven waistline or a visible rib hump on forward bending. The screening is there to help you make that decision earlier — not to make it for you. Results vary between individuals, and when in doubt, consult a professional.
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Frequently asked questions
- Can I use a scoliometer on myself?
- Not reliably. The test requires bending forward while someone else places the instrument across your back and reads it. Ask another person to take the measurement.
- How far forward should the person bend?
- Until the back is roughly horizontal, with arms hanging freely. A full toe-touch rounds the spine and can hide the rotation the test is looking for.
- Where on the back should I measure?
- Move through the thoracic, thoracolumbar and lumbar regions and record the highest reading, noting which region it came from.
- How often should the measurement be repeated?
- For children during a growth spurt, roughly every two to four weeks is common; for adults, monthly is usually enough. Consistent intervals matter more than frequency.
- Does a phone case affect the reading?
- It can. A thick or uneven case tilts the phone and introduces a consistent offset. Measure without a case where possible, and keep the setup identical between sessions.
Related guides
- Adam’s Forward Bend Test: instructions and limitations — the screening position in full detail.
- What is a normal scoliometer reading? — interpreting the number you have just recorded.
- ATR versus Cobb angle — what your reading does and does not tell you about the spine.
- What is a scoliometer? — what the instrument actually measures.
Reference: van West HM, Herfkens J, Rutges JPHJ, et al. The smartphone as a tool to screen for scoliosis, applicable by everyone. European Spine Journal 2022;31:990–995. This research assessed smartphone-based ATR screening as a method and did not evaluate any specific application.