Scoliosis is an abnormal curvature of the spine. The spine bends to one side of the body, causing the torso to compress on that side. The ribs on that side will be closer together while the ribs of the other side will be farther apart. Scoliosis also involves a rotation of the spine, in which the individual vertebrae bones twist around the long axis of the spine.
It's estimated that 2% to 4% of all children ages 10 to 16 have detectable scoliosis. An equal number of boys and girls develop scoliosis. When boys are affected, it usually develops in early childhood.
Most people with scoliosis have barely noticeable curvatures; however, girls are more likely to develop scoliosis bad enough to need treatment.