What Is the Anatomy of the Spine?
- Our spine is an engineering marvel that supports our weight and ties our body together.
- The spine consists of a column of small bones (vertebrae) that range in size from 2-3 inches to 5-6 inches in diameter.
- It is divided into anatomical sections. These are the
- cervical spine (neck), which has seven vertebrae;
- thoracic spine (upper back), which has 12 vertebrae to which the ribs are attached;
- lumbar spine (lower back), which has five vertebrae;
- sacrum, which consists of five bones that are fused or stuck together; and
- coccyx, which is made up of four tiny bones.
- When viewed from the front, the normal spine appears to be straight, but when viewed from the side, the normal spine has two gentle S curves. One curves outward in the upper back (called kyphosis by physicians), and the other curves inward in the lower back (known as lordosis).
What Is Scoliosis?
Scoliosis is an abnormal curvature of the spine. In scoliosis, the spine curves to the side when viewed from the front, and each involved vertebra also twists on the next one in a corkscrew fashion. This twisting is known as rotoscoliosis. This may cause one shoulder to be higher than the other or one side of the ribcage or lower back to be more prominent (humpback). If there is both a sidewise curvature and increase in the outward curvature of the upper back, this condition is called kyphoscoliosis. It is more common in children with neuromuscular diseases. A curve with a right-sided prominence is called dextroscoliosis, and a left-sided prominence is levoscoliosis. Generally, children with idiopathic (of unknown cause) scoliosis have two sidewise curves in opposite directions, but these may not be of the same size or severity.
What Are the Types of Scoliosis?
There are multiple types of scoliosis, classified by age of onset and/or cause. These include the following:
- Congenital scoliosis is present at birth and caused by vertebrae that are not properly formed prior to birth. Part of a vertebra maybe missing or wedge-shaped, and/or abnormal bony bridges between two or more vertebrae may be present.
- With infantile scoliosis, patients are younger than 3 years of age. It is more common in boys and may resolve on its own with only observation. Generally, this type of scoliosis has less of a rotational component than other types.
- Juvenile scoliosis is seen in children 3-10 years of age. It is more common in girls than boys and is at the greatest risk of progression of all types, with the highest risk of progression in girls.
- Idiopathic scoliosis is the most common type of scoliosis. This type is seen in children 11-16 years of age. It is also more common in girls, and they are at higher risk of progression of the curvature. The term idiopathic refers to any medical condition that arises spontaneously without a known cause.
- Neuromuscular scoliosis is caused by any of a number of associated disease processes that affect the neurologic or muscular systems. This may include cerebral palsy, muscular dystrophy, metabolic diseases, and connective tissue disorders such as Marfan's syndrome. The age of onset is variable and depends on the disease process.
- Adult-acquired scoliosis is due to acquired degenerative changes as the spine ages in patients over the age of 18.
Medically Reviewed by a Doctor on 12/13/2016
Aimee V. HachigianGould, MD
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