Scoliosis Info

• What is Scoliosis?
• Adolescent, Infantile, Juvenile, Adult
• Type of Curve/Non-Structural or Structural/Apical location
• Scoliotic Pattern
• Cobb Angle Measurements
• Scoliosis Classifications – Mild, Moderate, Severe

Scoliosis is a disorder where the spine is curved laterally, or away from center, and is typically coupled with rotation of the vertebrae. Scoliosis strikes most frequently during adolescence – about 85% of scoliosis diagnoses. Onset during adolescence is known as adolescent idiopathic scoliosis or AIS. Infantile scoliosis is diagnosed before three/four years of age and juvenile scoliosis between age three/four and nine/ten years. Scoliosis, in some cases, may go undetected until a person is an adult. Generally, the earlier the onset of scoliosis, the higher the risk of curve progression.

Non-structural (functional) scoliosis

A non-structural (functional) curve disappears when the patient is lying down or bending to the side. Temporary scoliosis is not unheard of, and clinical experience has shown it is most commonly seen in the lumbar spine as a result of an injury to an intervertebral disc with secondary muscle spasm. “Controlled clinical studies are consistent with the possibility that nonstructural and structural scolioses are functionally interchangeable at least in early stages of spinal deformity.”¹

Structural Scoliosis

Typically structural curves are associated with a loss of spinal flexibility of the rotated vertebrae. Vertebrae are fixed and a rigid rib cage is apparent if the thoracic vertebrae are involved. When x-rays are taken of a structural scoliosis, the curve is always present regardless of position, but may exhibit variation of angle(s).

Apical Location

Curves are classified according to direction of the apex and the vertebral location, for example, the most common type of scoliotic curve is a Right Thoracic Curve.

Scoliotic Pattern

Some scoliosis patients present with ‘S’ shaped curves -double/triple curved scoliosis. With this type of curve, one curve is usually greater than the other(s), and is referred to as the the primary (major) curve. The curve(s) of lesser degree is/are considered the secondary (compensatory or minor) curve(s). Some cases of scoliosis are a single, or ‘C’ shaped curve.

Cobb Angle Measurement

Scoliosis is measured in degrees by a measurement known as a Cobb angle.  Any measurement under 10º is not considered a scoliosis. To find the Cobb angle measurement, a line is drawn from the top edge of the upper vertebra with the most tilt, and also from the bottom of the lower vertebra with the most tilt. “In a normal spine this procedure will yield two parallel lines, with an angle of ‘0.’ In scoliosis, the vertebrae are tilted according to the severity of the curvature. For any given curvature, the vertebrae at the top and bottom of the curve are the most tilted and are used as a basis for the Cobb angle measurement.”² The Cobb angle is the universal standard to diagnose scoliosis and to assess whether a curvature has stabilized or is getting worse.³ However, the Cobb angle is an imperfect measurement and there is significant debate on the degree required to determine whether a curve is getting better or worse. Generally the margin of error in Cobb angle measurement is considered to be 5º.

Mild, Moderate or Severe

“Scoliosis is generally classified as mild (10-24º) Cobb angle measurement, moderate (25-50º) and severe >50º with some quantitative variation among sources, depending on the perspective of the author of any given article.”⁴

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¹, ²,⁴ Hawes, Martha C., Ph.D., Scoliosis and the Human Spine: A critical review of clinical approaches to the treatment of Spinal deformity in the United States, and a proposal for change., Tuscon, Arizona: West Press, 2003.

³  Moe’s Textbook of Scoliosis and Other Spinal Deformities, Third Edition, eds Lonstein J, Bradford D, Winter R, Ogilvie J, WB Saunders, Philadelphia.

Information contained on this site is for informational purposes only. It is not meant for diagnosis. You must consult a physician for a medical opinion.