What is Scoliosis?
Your spine has three slight curves: one in the neck, one in the upper back, and another in the lower back. These curves are normal and can be seen from a side view. If your spine has a side-to-side curve, this condition is called scoliosis.

Apart from the cosmetic disfigurement, untreated scoliosis can also cause back pains, fatigue, nervous system problems, and heart and lung problems.

An idealized drawing of a normal spine is shown, with the terms commonly used to describe different locations on the spine. Cervical vertebrae (spine bones) tend to be closest to the neck, whereas thoracic vertebrae are about chest high. The lumbar and sacrum vertebrae are in the lower back region.

What Causes Scoliosis?
No one knows what causes the most common form of scoliosis (80% of all cases), called "idiopathic scoliosis" (idiopathic is another word for "unknown"). What is known is that scoliosis tends to run in families, so that a person with scoliosis often has parents, sisters, or brothers with scoliosis. One fact that has been noticed by researchers is that children with adolescent idiopathic scoliosis tend to be taller and grow later than children without scoliosis. It is still not clear what this tells us about what causes idiopathic scoliosis, however.

Less often, scoliosis is the byproduct of other conditions, such as defects of the spine already present at birth ("congenital scoliosis"), disorders of the central nervous system (cerebral palsy), muscle diseases (muscular dystrophy), disorders of connective tissue (Marfan’s syndrome), and genetic abnormalities (Down’s syndrome).

Who Gets Scoliosis?
About 2-3% of the US population, or about 6 million people, have some form of scoliosis, but only 0.2-0.3%, or about 1 million, need active treatment. For the majority of cases, which are idiopathic scoliosis, girls are most likely to be diagnosed, are five times more likely to need treatment, and their curvatures more likely to increase. Again, the reason for this is not known, but the fact should prove useful to researchers attempting to find the cause of idiopathic scoliosis.

What does Scoliosis look like?
For those who have a severe curvature, there are some possible physical effects. Leg lengths may be relatively unequal, which can be upsetting , even if it is not disabling, or even noticeable by others. The rib cage can become oval in shape, with ribs more prominent on one side than on the other. This can make the breasts look uneven. Lung function can be affected if there are bone irregularities, which can make it difficult to participate in sports.

But even severe curves may be well-compensated for and are therefore not necessarily disfiguring or sexually limiting. Girls with scoliosis should not expect any significant limitation of their activities.

Types of Scoliosis:
There are many ways to describe the scoliotic curve. The terms used to describe scoliosis are often combined together, as in "severe adolescent idiopathic scoliosis". The four different categories most commonly used to describe scoliosis are explained here:

By Location
Often a scoliotic curve will appear in a unique location along the spine, and someplaces are more likely to have curves than others. Depending on where the curveis, the back often will appear different, and possibly require slightly differenttreatments to correct and/or contain the scoliosis.

• Thoracic curve: One of the most common idiopathic patterns, this curve is usually tilted to the right and is easier to spot, due to the more obvious twisting of the ribs.
• Thoracic-lumbar curve: Another fairly common idiopathic pattern, and tends to be longer. The rib twisting and rib hump is less obvious than with the thoracic curve, but still prominent.
• Lumbar curve: These curves appear in the lower back and tend to be on the left. The scoliosis caused by this kind of curve is not as visible, but tends to be more rigid than other kinds of curves, a concern for many women who are planning pregnancies.
• Double major curve: The hardest of all the curves to spot when the two curves are in opposite directions, as is usually the case. This is because the two curves tend to balance each other out, and the back appears almost normal.

right thoracic		left thoracic
right thoracolumbar		double major

By Cause:
Sometimes it is more useful to classify scoliosis by cause.

• Idiopathic scoliosis: About 80% of individuals with scoliosis have "idiopathic scoliosis", which means that the cause of the condition is unknown.
• Osteopathic scoliosis: Osteopathic means "resulting from a bone abnormality", and these normally occur while in the womb. Also called congenital scoliosis, these birth defects affect the shape of the spinal bones, called vertebrae. Most congenital curves will not progress, but a few require treatment.
• Other causes: Scoliosis is sometimes caused by other conditions such as trauma to the spine, neuromuscular conditions (such as polio, muscular dystrophy or cerebral palsy), connective tissue disease (Marfan’s syndrome), and spinal cord tumors.

By Curve:
Sometimes a curve is characterized by the severity of the curve, measured by the Cobb method. The Cobb method makes lines from two tilted vertebrae (spine bones) along the curved part of the spine, and where they intersect the Cobb angle, pictured below, is formed. Since where the lines actually intersect is off the page, a rule of geometry is used to recreate the angle, drawing additional lines perpendicular to the original lines. Decisions about treatment are often made based on curve severity.

• Mild Curve: between 10-25^o
• Moderate Curve: between 25-35^o
• Severe Curve: Greater than 40^o