Scoliosis (skoh-lee-oh-sis) is an abnormal, side-to-side curve of the spine.  Scoliosis should not be confused with poor posture.  The word idiopathic (id-ee-uh-path-ik) means that there is no known reason for the curve in the spine. The condition is not rare. It is most common in girls between the ages of 10 to 18 − many of whom have such mild forms that they are not aware of it or treated for it. There are three types of idiopathic scoliosis: