The word scoliosis is derived from the Greek word meaning “crooked.” Scoliosis is defined as a lateral deviation of the normal vertical line of the spine. The lateral curvature of the spine also is associated with rotation of the vertebrae. This produces a three-dimensional deformity of the spine that occurs in the sagittal, frontal, and coronal planes.
The Scoliosis Research Society (SRS) recommends that idiopathic scoliosis be classified according to the age of the patient when the diagnosis is made. Infantile scoliosis occurs from birth to 3 years of age; juvenile idiopathic scoliosis, between the ages of 4 and 10 years; and adolescent idiopathic scoliosis, between 10 years of age and skeletal maturity. This traditional chronologic definition of scoliosis is important because major differences exist between the subtypes (Table 44.1).
