Types of Scoliosis Curves, and How the Cobb Angle Measures Severity
A new scoliosis diagnosis report can feel like it is written in a foreign language.
Thoracic, thoracolumbar, Cobb angle of 28 degrees — the words get used fast, often with no real explanation attached.
Scoliosis curves are described in two ways: where they sit on the spine and how many curves are present.
Severity is then measured using something called the Cobb angle, a method that’s been in use since the 1940s and is still the standard today.
This guide walks through both, so the next time you’re handed a scoliosis report, you’ll actually know what it’s telling you.
Thoracic, Lumbar, and Thoracolumbar Curves Explained
Quick note: this is about where a curve sits on the spine, not why it developed. If you’re after the causes of scoliosis, we’ve covered that separately. Here, we’re purely talking about location.
Thoracic Curves (upper/mid-back)
This is the most common curve type, sitting in the upper and mid-back. It’s often what people picture when they hear “scoliosis” — one shoulder blade riding higher than the other, or a rib hump that shows up when bending forward.
Thoracic curves are usually right-sided and tend to get picked up during the teenage growth spurt.
Lumbar Curves (lower back)
Lumbar curves sit lower down the spine. They’re harder to spot visually (since there’s no rib cage to exaggerate the shape), but they can show up as an uneven waistline or one hip sitting higher than the other.
Lumbar curves are more often left-sided. And since this is where the nerves branch out toward the legs, they’re sometimes linked to lower back discomfort.
Thoracolumbar Curves (spanning both regions)
A thoracolumbar curve sits right at the junction between the two regions above. Because it bridges both areas, it can produce a bit of everything — some rib prominence, some waist or hip asymmetry — all as part of one long curve rather than two separate ones. It’s less common than a straightforward thoracic curve, but it’s assessed and measured the same way.
Single (C-Shaped) vs Double (S-Shaped) Curves
Curve location tells you where the problem is. The curve pattern tells you how many bends the spine has made to deal with it.
Single (C-Shaped) Curves
A single curve bends one way only — the spine looks like the letter C when viewed from behind. This is usually a lumbar or thoracolumbar curve.
Sometimes it sits alone. Other times, the rest of the spine forms a smaller, flexible curve above or below it, just to keep the head balanced over the pelvis.
That smaller curve is called a compensatory curve — and unlike the main one, it’s usually not rigid. It tends to ease back on its own once the primary curve is treated.
Double (S-Shaped) Curves
A double curve (sometimes called a double major curve) bends one way in the thoracic spine and the opposite way further down, creating the classic S shape.
Here, both curves are structural, meaning neither one fully straightens out when you bend sideways. That’s the key difference from a compensatory curve.
An S-shaped spine can sound more serious than a C-shaped one, but the curve pattern alone doesn’t decide severity — the Cobb angle does. Which brings us to the next part.
What the Cobb Angle Actually Measures
The Cobb angle is the number every scoliosis report is built around. It was developed in 1948 by American orthopaedic surgeon Dr John Cobb, and it’s still the standard way to measure a spinal curve.
Here’s how it works.
On a standing X-ray, the doctor identifies the two vertebrae that tilt the most, at the very top and very bottom of the curve — these are called the end vertebrae. A line is drawn along the top edge of the upper one, and another along the bottom edge of the lower one. Where those two lines would meet, if extended out, forms an angle.
That angle, measured in degrees, is your Cobb angle.
The bigger the number, the bigger the curve. Anything under 10 degrees isn’t classed as scoliosis at all — it’s considered normal spinal variation. Above that is where the real measuring and the real decision-making begin.
Mild vs Moderate vs Severe: What the Numbers Mean
This topic is highly anticipated but causes the most disagreement online.
Different sources draw the mild, moderate, and severe lines in slightly different places, and a lot of them are based on overseas guidelines that don’t quite match Australian practice.
What matters more than the exact label is how likely a curve is to keep progressing — which is the approach taken by the Royal Australian College of General Practitioners (RACGP), the clinical body we lean on for this section.
Mild Curves
Under 25 degrees, a curve is generally considered unlikely to progress. These curves are often just monitored with regular check-ups rather than actively treated, though bracing can still come up in conversation for younger patients who have a lot of growing left to do.
Moderate Curves
Between 25 and 50 degrees, a curve is more likely to progress while the skeleton is still growing. This is usually the range where bracing, targeted exercise, or hands-on care like osteopathy gets discussed seriously, alongside closer monitoring.
Severe Curves
Above 50 degrees, a curve is likely to keep progressing even after growth has finished, which is why curves in this range are typically referred to a specialist for an opinion, including whether surgery is appropriate.
Worth knowing: exact cut-offs vary between sources and clinicians — some place mild scoliosis as low as 10 degrees. Your osteopath or GP will always read your specific number alongside your age, growth stage, and curve pattern, not the angle in isolation.
How We Assess Curve Type and Degree
Knowing the curve type and its degree matters for one reason: it shapes the treatment plan.
A mild, single lumbar curve is managed very differently from a moderate double curve, so getting an accurate picture early on makes a real difference down the road. Here’s how our osteopaths in Brisbane work through that at Prime Health Hub.
The Scoliometer Assessment
We start with a scoliometer, a small handheld device run along your spine while you bend forward. It measures the angle of trunk rotation — the twist that goes hand in hand with a scoliosis curve — and gives us an early, non-invasive read on whether a curve needs further investigation.
You can read more about how we use a scoliometer in osteopathic assessment.
Digital Postural Assessment
Alongside the scoliometer, we run a digital postural assessment to map your posture, spinal alignment, and overall body symmetry. This gives us a visual, measurable baseline, so we’re tracking real change over time rather than relying on memory from one visit to the next.
When We Refer for X-Ray or EOS Imaging
A scoliometer and postural assessment tell us a lot, but only an X-ray gives an actual Cobb angle. Where it’s clinically appropriate, we refer for standing X-rays or EOS imaging (a low-dose imaging technology) to confirm curve type, measure the Cobb angle precisely, and guide the rest of your treatment plan.
Reading your own scoliosis report shouldn’t get confusing. If you’ve recently been given a Cobb angle and want it explained properly, or you’re after ongoing scoliosis treatment in Brisbane, our team at Prime Health Hub can talk you through exactly what your results mean and what your options look like from here.
Inversions or Headstands Without Guidance
Hanging upside down or holding a headstand.
The concern: These put unusual pressure through the neck and spine — pressure that’s distributed unevenly when the spine itself is curved.
The takeaway: Get proper instruction first, and if you’re managing a larger curve, it’s worth skipping altogether unless your practitioner says otherwise.
High-Impact Repetitive Jumping (for more significant curves)
Think box jumps, skipping marathons, or repeated hard landings in sport.
The concern: For people managing a bigger curve specifically, the repeated compressive force through the spine adds up.
The takeaway: This is far less of an issue for mild curves — it’s the more significant ones where it’s worth checking in with your osteo before making it a regular habit.
Exercises for Mild vs More Significant Curves
Your spinal curve matters. A 12-degree curve and a 45-degree curve aren’t the same situation — they don’t call for the same approach.
Curve size is measured using something called the Cobb angle. Generally, anything under about 20–25 degrees is considered mild (the exact cut-offs vary from source to source).
For Mild Curves (roughly <20–25°)
Most general exercise is genuinely fine here. Focus on staying active, building overall fitness, and adding in the safe exercises above for extra core and postural support. Regular check-ins (with your GP, osteopath, or specialist) help keep an eye on any changes over time — you’re not signing up for constant monitoring, just sensible check-ins.
For Moderate to More Significant Curves
This is where a personalised plan matters a lot more than a generic list. Curve-pattern-specific programs (like Schroth-based PSSE) become genuinely relevant, and depending on age and growth stage, exercise is often used alongside other treatments like bracing rather than instead of it. Before ramping up training intensity or starting a new sport, it’s worth getting the plan checked by whoever’s treating you.
Should You See an Osteopath Before Starting?
Short answer: it helps, and it doesn’t have to be a big production.
Exercise is broadly safe and genuinely encouraged for people with scoliosis — that’s not in question. What varies enormously is which exercises suit your curve.
Two people can both have “scoliosis” and need almost opposite advice. It all depends on where the curve sits, which way it bends, and how flexible their spine is.
That’s really where an osteopath earns their keep. Rather than working off a generic list (even a good one, like this one), a Brisbane osteopath at Prime Health Hub can assess your specific pattern and build a plan around it — what to lean into, what to ease off, and how to progress safely over time.
If you’re in Brisbane and unsure where to start, that first assessment is a pretty low-pressure way to get some clarity.
Frequently Asked Questions
What Is a Bad Cobb Angle for Scoliosis?
There’s no single “bad” number, but curves above 25 degrees are more likely to need active treatment, and curves above 50 degrees are more likely to keep progressing without it.
At What Cobb Angle Is Surgery Required?
Surgery is typically only considered once a curve reaches around 45 to 50 degrees or more, and even then, the decision depends on age, remaining growth, and how the curve is affecting daily life — not the angle alone.
How Do You Calculate a Cobb Angle?
A doctor draws a line along the top of the most tilted vertebra above the curve, and another along the bottom of the most tilted vertebra below it, then measures the angle formed where those two lines intersect.
References:
Parr, A & Askin, G 2020, “Paediatric scoliosis: Update on assessment and treatment,” Australian Journal of General Practice, vol. 49, no. 12. Available at: https://www1.racgp.org.au/ajgp/2020/december/paediatric-scoliosis
Thuaimer, A & Bell, DJ 2026, “Cobb angle,” Radiopaedia.org. Available at: https://radiopaedia.org/articles/cobb-angle