The spine, or backbone, is made up of small bones (vertebrae) stacked -- along with discs -- one on top of another. A healthy spine when viewed from the side has gentle curves to it. The curves help the spine absorb stress from body movement and gravity.
When viewed from the back, the spine should run straight down the middle of the back. When abnormalities of the spine occur, the natural curvatures of the spine are misaligned or exaggerated in certain areas, as occurs with lordosis, kyphosis, and scoliosis.
Doctors do not know what causes the most common type of scoliosis seen in adolescents. However, doctors do know that scoliosis tends to run in families. A disease, injury, infection, or birth defect also may be to blame.