Scoliosis is a disorder that causes an abnormal curve of the spine, or backbone. The spine has normal curves when looking from the side, but it should appear straight when looking from the front. People with scoliosis develop additional curves to either side, and the bones of the spine twist on each other, forming a "C" or an "S" shape in the spine.
Scoliosis is about two times more common in girls than boys. It can be seen at any age, but it is most common in those over 10 years of age. Scoliosis is hereditary in that people with scoliosis are more likely to have children with scoliosis; however, there is no correlation between the severity of the curve from one generation to the next.