Scoliosis is a medical condition in which a person's spine is curved from side to side. Although it is a complex three-dimensional deformity, on an X-ray, viewed from the rear, the spine of an individual with scoliosis may look more like an "S" or a "C", rather than a straight line. Scoliosis is typically classified as either congenital (caused by vertebral anomalies present at birth), idiopathic (cause unknown, subclassified as infantile, juvenile, adolescent, or adult, according to when onset occurred), or neuromuscular (having developed as a secondary symptom of another condition, such as spina bifida, cerebral palsy, spinal muscular atrophy, or physical trauma). A lesser-known cause of scoliosis could be a condition called Chiari malformation.
Longitudinal studies reveal that the most common form of the condition, late-onset idiopathic scoliosis, is physiologically harmless and self-limiting. The rarer forms of scoliosis pose risks of complications.