Scoliosis is a lateral curving of the spine with the thoracic area being the most commonly affected. It can be classified as functional or structural. Functional scoliosis is the result of another deformity and is corrected by treating the underlying problem. Structural scoliosis is most often idiopathic although it may be congenital or secondary to another disorder. There is a growing body of evidence that idiopathic scoliosis is probably genetic but the etiology is not completely understood. Structural scoliosis is more progressive and causes changes in supporting structures, such as the ribs. Management includes observation, bracing, and surgical fusion. Patients with idiopathic curves of less than 25 degrees are observed for progress until they have reached skeletal maturity. Bracing is recommended for adolescents with curves between 30 and 45 degrees, while curves greater than 45 degrees usually require surgery. The deformity may occur at any age, from infancy through adolescence, but the best prognosis belongs to those who are almost fully grown and whose curvature is of a mild degree. Idiopathic scoliosis most commonly occurs in adolescent girls.