Diagnosing Adolescent Idiopathic Scoliosis

lines drawn on diagram to measure degree of curvature

The degree of curvature is measured by drawing lines at the first and last tilted vertebrae, then drawing lines perpendicular to those lines. Where that second set of lines intersect, called the Cobb angle, is where the degree of the curve is measured.

Early detection of adolescent idiopathic scoliosis is important for successful treatment of this spinal deformity. It is important to be evaluated at an advanced spine center as soon as possible, since early and expert intervention can keep the condition from getting worse. The side-to-side spine curve of adolescent idiopathic scoliosis may be clearly visible during an adolescent’s annual check-up, and a pediatrician may be the first to refer a family to a trained orthopedic physician. In addition, many schools screen their students for scoliosis, so a school nurse may be the first to bring the condition to parents’ attention. Physical education instructors may also detect signs of adolescent scoliosis. Parents who have had other family members with the condition or who know what to look for (see Symptoms of Adolescent Idiopathic Scoliosis) may notice an excessive curve in the spine, or teens may complain that their clothing doesn’t fit right.

When adolescent idiopathic scoliosis is suspected, a trained physician will take a complete medical history and perform a physical and visual examination of the adolescent. (It is not necessary to have X-rays taken prior to consulting a pediatric spine specialist, as these will routinely be ordered by the specialist; if any early X-rays exist, however, they should be brought to the visit.)

To assess the curve, determine flexibility, and check for muscle weakness, the adolescent will be asked to stand, sit, bend over, and walk. The doctor will also check reflexes to see whether there is nerve damage.

To establish a proper diagnosis of adolescent idiopathic scoliosis and rule out other causes of spinal deformity, the physician will also want to learn:

  • When the curve was first noticed. If a curve starts at a young age, or before a girl begins her period, it is more likely to progress.
  • Family history, since scoliosis is thought to have a genetic component.
  • If there is any pain. Adolescents do not usually experience pain from scoliosis, but if a child is suffering from back pain, the doctor needs to its precise location and what triggers the pain.
  • If the child experiences any numbness, tingling, or weakness, which may indicate compression of nerves. Changes in bowel or bladder function may also indicate nerve damage. 


Current physical findings and measurements will be compared to prior measurements (height, for example) and any notes on the child's spine or unusual features of other bony body parts. The doctor will look for asymmetries (uneven appearances) in the shoulders, ribs, chest, leg length, and other unusual findings, such as if the torso doesn’t appear to be evenly positioned over the pelvis, or the child’s head seems off-center.

Once scoliosis is diagnosed, there is always the question of a curve's progression. The Risser sign measures the spine’s maturity using an X-ray of an area of the hipbone (from 0-5, with 0 meaning least growth of spine and most risk of progression).


Common X-ray images taken to diagnose adolescent idiopathic scoliosis are:

  • Back and front while standing
  • Sideways view while bending forward at the waist
  • Sideways view while standing
  • Traction films are taken when the spine is pulled and held in a particular position; these films are only occasionally taken

If the curve pattern is not typical or if there is something unusual on the X-ray, a physician may order one or more of the following tests to provide more details:

  • Computerized tomography (CT) is a noninvasive procedure that uses X-rays to produce a three-dimensional image of the spine. A CT shows more details than an X-ray and can reveal the nerves and spinal cord, as well as detecting rib cage problems.
  • Magnetic resonance imaging (MRI) uses magnetic fields and radio-frequency waves to create an image of the spine that reveals the discs, nerves, spinal canal, and other details that can’t normally be seen on an X-ray. An MRI may also be used to check for spinal-cord compression. Sometimes a contrast agent is injected into a vein in the hand or arm during the test, which highlights certain tissues and structures to make details even clearer. An MRI does not expose a child to radiation.
  • Electromyogram and nerve-conduction studies (EMG/NCS) measure the electrical activity in the nerves and muscles. They may identify nerve damage or nerve compression. 
  • Pulmonary function tests may be ordered to determine if lung function is restricted due to decreased space in the chest from the spinal deformity.

Reviewed by: Kai-Ming Fu, MD, PhD
Last reviewed/Last updated: August 2021

Our Care Team

  • Professor of Neurological Surgery, Spinal Surgery
  • Co-Director, Spinal Deformity and Scoliosis Program
  • Director, Spinal Trauma/Adult and Pediatric Spinal Surgery
Phone: 212-746-2260
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  • Assistant Professor of Neurological Surgery
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  • Assistant Professor of Neurological Surgery
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