Signs and symptoms of scoliosis may include:

• Uneven shoulders
• One shoulder blade that appears more prominent than the other
• Uneven waist
• One hip higher than the other

If a scoliosis curve gets worse, the spine will also rotate or twist, in addition to curving side to side. This causes the ribs on one side of the body to stick out farther than on the other side.

Doctors don't know what causes the most common type of scoliosis — although it appears to involve hereditary factors, because the disorder tends to run in families. Less common types of scoliosis may be caused by:

• Neuromuscular conditions, such as cerebral palsy or muscular dystrophy
• Birth defects affecting the development of the bones of the spine
• Injuries to or infections of the spine

Risk factors for developing the most common type of scoliosis include:

• Age. Signs and symptoms typically begin during the growth spurt that occurs just prior to puberty.
• Sex. Although both boys and girls develop mild scoliosis at about the same rate, girls have a much higher risk of the curve worsening and requiring treatment.

Family history. Scoliosis can run in families, but most children with scoliosis don't have a family history of the disease.

While most people with scoliosis have a mild form of the disorder, scoliosis may sometimes cause complications, including:

• Lung and heart damage. In severe scoliosis, the rib cage may press against the lungs and heart, making it more difficult to breathe and harder for the heart to pump.
• Back problems. Adults who had scoliosis as children are more likely to have chronic back pain than are people in the general population.
• Appearance. As scoliosis worsens, it can cause more noticeable changes — including unlevel shoulders, prominent ribs, uneven hips, and a shift of the waist and trunk to the side. Individuals with scoliosis often become self-conscious about their appearance.