Scoliosis is defined as curvature of the spine greater than 10 degrees, as measured on an X-ray. Anything less is considered normal variation in a normal individual.

Scoliosis may be divided into five principal types:

  • Idiopathic Scoliosis — This is the most common. The name idiopathic means “the cause is unknown.” Affected children are otherwise healthy and normal. The spine shows no abnormality of the bones themselves on X-rays or by looking at it directly in the operating room. While the overall incidence is equal in girls and boys, progressive or severe idiopathic scoliosis is about six to seven times more frequent in girls than in boys.
  • Congenital Scoliosis — Congenital means that the child is born with scoliosis, and it is caused by an abnormality of one or more vertebrae. The vertebrae don’t form properly, which can be seen on X-ray and directly in the operating room.
  • Neuromuscular Scoliosis — This is scoliosis that occurs in children who have a disease of the nervous system, such as cerebral palsy.
  • Syndromic Scoliosis — This type of scoliosis occurs in children with a syndrome, such as Marfan syndrome, or one of the skeletal dysplasias such as achondroplasia.
  • Postural Scoliosis — Also known as “hysterical scoliosis,” postural scoliosis may be a result of pain, as the child tilts sideways to alleviate the pain. It can be reversed by taking care of the primary problem by relieving the pain or by having the child lie flat. X-rays don’t show any abnormality of the vertebrae.

Progressive, severe scoliosis can produce three major problems:

  • If the part of the spine that is in the chest, called the thoracic spine, curves more than 90 percent, the volume of the chest can be reduced so much that the function of the heart and lungs may be compromised. The heart may have to work harder to pump the normal volume of blood or the affected individual may have difficulty breathing.
  • Severe curvature of the lower half of the spine that connects the chest with the pelvis, known as the lumbar spine, may push the contents of the abdomen against the chest and interfere indirectly with heart and lung function. Curvature of the lumbar spine also may alter sitting balance and posture.
  • Severe curvature of either the thoracic or the lumbar spine, or both, eventually becomes visible to others. The resulting tilting and twisting of the back, shoulders and pelvis may produce an appearance that the affected individual finds unacceptable. Since the most common scenario for idiopathic scoliosis is a girl at around the time of puberty, when body image is developing hand-in-hand with self-esteem, the condition can pose significant psychological and emotional challenges.


Idiopathic scoliosis usually is not a painful condition. The incidence of back pain in scoliosis is approximately 30 percent, which is the same as the incidence of back pain in children without scoliosis. There are certain exceptions in which an associated disease of the central nervous system, such as a fluid collection in the spinal cord, may produce pain as well as scoliosis.