There are three parts to the spine: the cervical spine (neck), the thoracic spine (mid back), and the lumbar spine (lower back). Usually, the spine looks relatively straight when viewed from the front or back. In patients with scoliosis, the spine curves sideways, usually into the shape of an S or a C. An S-shaped curve is also called a double curve. A C-shaped curve is also called a single curve.
There are five main curve patterns:
Type I curve
There are two curves—an S-shaped curve that involves the thoracic (mid-back) and lumbar (lower back) spine. The lumbar curve is bigger than the thoracic curve.
Type II curve
There are two curves—an S-shaped curve that involves the thoracic (mid-back) and lumbar (lower back) spine. The thoracic curve is bigger than the lumbar curve.
Type III curve
A shorter, C-shaped curve that involves the thoracic (mid-back) spine.
Type IV curve
A longer, C-shaped curve that involves the thoracic (mid-back) and lumbar (lower back) spine.
Type V curve
There are two curves—an S-shaped curve that involves the thoracic spine. One curve is in the mid-thoracic area and the other curve is in the upper thoracic area. The mid-thoracic curve is bigger than the upper thoracic curve.
Physical changes to the body
When a curve in the spine develops, there are also changes to the rib cage, shoulders, and hips. As the curve(s) in the spine start to increase in size, the spine begins to twist. The ribs, which are attached to the spine, also twist. The ribs become more pronounced on the side of the curve. This is called a “rib prominence”.
A rib prominence can be clearly seen when a child with scoliosis bends over to touch their toes. The rib prominence is much higher on the side where the spine is curved. In larger curves, the rib cage may twist so much that the chest may push forward on one side.
Some girls may also notice that one breast appears larger than the other. The shoulders are also affected. Usually, one shoulder is higher than the other. Sometimes, in more severe curves, the shoulder is also pushed forward. Depending on the location of the curve(s), one hip may be higher than the other. Alternately, one hip may appear to be pushed forward on one side.