A normal spine appears straight when observed from the back. Scoliosis (derived from Greek word - skolios - meaning crooked) refers to an abnormal sideward curvature of the spine. In addition to the sideward bend in the spine, some amount of rotation of the spine is also present. The sideward bend and rotation lead to a prominence of the ribs on one side of the back and an asymmetry of the waist and shoulders. On the other hand, an abnormal forward bend of the spine is called kyphosis (hunch-back).