Scoliosis is diagnosed with a physical examination and a standing X-ray of the whole spine. The two things that matter most for what happens next are how big the curve is and how much growing your child has left. This page explains how we measure both.
Reviewed by Dr. Kshitij Chaudhary — Last reviewed October 2026
When should I see a doctor?
Book a visit if you notice any of the signs of scoliosis, or if you're simply worried. It's also worth being seen soon if:
- A known curve seems to have changed over a few months
- Back pain is persistent, wakes your child at night or doesn't settle
- There is weakness, numbness or tingling in the legs, or any change in bladder or bowel control
- The curve looks unusual, for example a curve to the left in the upper back
These are uncommon with idiopathic scoliosis. They are worth checking so that other causes can be ruled out.
How is it diagnosed?
At the first visit we will:
- Ask about your child's health, growth and any family history of scoliosis
- Measure height
- Examine the back, shoulders, hips and legs, including a check of nerve function
- Do the Adam's forward bend test. Your child bends forward at the waist, and we look for any rotation of the ribs or lower back. A hand-held tool called a scoliometer measures it. A rotation of more than about 5 to 7 degrees suggests scoliosis may be present
- Take X-rays, then go through the results with you and answer your questions
- Recommend a plan
The diagnosis is confirmed on a standing X-ray of the whole spine, taken on a single film. Standing matters, because the spine behaves differently when it carries weight. Separate films of each region don't show overall alignment as well.
How is the size of the curve measured?
We draw a line along the top of the highest tilted vertebra and another along the bottom of the lowest tilted vertebra. The angle between them is the Cobb angle. Measurements can differ by up to 5 degrees from one X-ray to the next, even when the curve hasn't truly changed. That's one reason we look at trends over several visits and don't react to a single number.
(Image to add: Cobb angle drawn on a standing X-ray)
Will my child need an MRI?
Not for a typical curve. An MRI checks the spinal cord and nerves. We recommend one if the curve pattern is unusual (for example a left-sided curve in the upper back), if there is pain or any nerve symptom, if the curve starts at a young age or is progressing quickly, and sometimes before surgery.
Will the curve get bigger?
There isn't always a way to know. Two things matter most: how big the curve is now, and how much growing your child has left. In general, the younger the child and the bigger the curve when it's found, the higher the chance it will progress.
The riskiest time is the growth spurt, when a curve that is going to progress can grow by 1 to 2 degrees a month. Remember that most small curves stay small.
Once growth is over, curves under 40 degrees rarely get worse, though lower-back curves can occasionally creep on. Curves between 40 and 50 degrees behave differently from child to child. Curves over 50 degrees can keep growing slowly in adult life, by about 1 to 2 degrees a year.
How do you know how much growing is left?
We put several clues together:
- Height. We measure it at every visit. Two measurements a few months apart with no gain is the surest sign that growth is over
- The Risser sign. On the X-ray, a cap of bone appears along the top of the pelvis as growth finishes (see the table)
- Puberty. For girls, when periods began and breast development. For boys, voice change and facial hair
- A hand and wrist X-ray. This shows the growth plates in the hand, which close in a reliable pattern. It also lets us compare your child's "bone age" with their real age. We use it when the other clues disagree
The fastest growth happens in the roughly 18 months before the first Risser sign appears. Girls reach it earlier than boys, usually before their first period. Most girls finish growing 18 to 24 months after periods begin. Boys tend to keep growing into their late teens.
Risser stage | What it means |
0 | No bone cap yet. The growth spurt is ahead or under way |
1 | The cap first appears at the outer edge of the pelvis |
2 to 4 | The cap spreads across the top of the pelvis over about 2 years. Growth is slowing |
5 | The cap has fused to the pelvis. Spinal growth is finished |
(Image to add: Risser stages on a pelvis diagram)
This information is for general education and does not replace a consultation with your doctor.