Scoliosis is an abnormal curvature of the spine, or backbone. Instead of a straight vertical line from the neck to the buttocks, the spine has a C- or S-shape.

Types of scoliosis include:

  • Structural—curvature with spinal deformity:
    • Congenital
    • Syndromic
    • Idiopathic
  • Functional—curvature without spinal deformity

Scoliosis may also be described as infantile, juvenile, or adolescent based on the child's age at onset.

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The different types of scoliosis have different causes.

Structural scoliosis—classified by the cause of the vertebral body defect:

  • Congenital—defect occurs during fetal development
  • Syndromic—defect occurs as a result of an underlying health condition that affects the nerves, muscles, or bones in the back and spine
  • Idiopathic—defect occurs without a specific cause, but is likely due to a combination of multiple genetic factors

Functional scoliosis may be caused by:

  • Muscle imbalances
  • Differing leg lengths
  • Conditions that cause muscles to remain tense and spasm

In some cases, scoliosis may be caused by damage to the vertebral body from:

  • Injury
  • Infection
  • Tumors