Normal Curves of Your Spine vs Scoliosis

We are suppose to have some curve to our spine. These curves are best viewed when looking at someone from the side. Thoracic and sacral curves are kyphotic, meaning the curve comes out on the back of your body (posteriorly convexed) to allow space for organs inside your torso. Cervical and lumbar curves are lordotic, meaning the curve goes towards the front of your body (concaved posteriorly).

The word scoliosis means curvature from Greek. Scoliosis is an abnormal curvature of the spine which can take several different shapes and forms. It most commonly involves the thoracic spine, however other regions of the spine can be involved. The abnormal curve of scoliosis appears as a side curvature of the spine that is visible in the frontal plane. These curves are seen best when looking at the front or back side of a body. The side-bending involved with scoliosis is typically combined with a rotation of the vertebrae, and often a reduced kyphosis in thoracic curves.

Most cases (about 85%) of scoliosis occur during adolescence and are idiopathic. Idiopathic means there is no known cause. Scoliosis is defined as a curve measuring at least 10 degrees on x-ray, and is usually observed when the curve is about 20 degrees.  Scoliosis is described by location, direction and number of frontal plane curves. These are commonly described as C or S curves. The primary curve is labeled by the side of its convexity, and not the direction of the side-bend. A rib hump is typically on the convexed side due to coupled motion of side-bending with rotation. Scoliosis is the most common spinal disorder in children and adolescents. Scoliosis is a life-long condition. Management of scoliosis includes exercises, bracing, physical therapy, and in some cases surgery.

Scoliosis - Curve Types: Thoracic Curve: One of the most common patterns in idiopathic scoliosis, 90% occur on the right side. Thoracolumbar Curve: Also a common pattern in idiopathic scoliosis, 80% occur on the right side. Lumbar Curve: Less visible on physical examination, 70% occur on the left side. Double Major Curve: Most common is a right thoracic with left lumbar curves creating an S curve.

To be diagnosed with scoliosis, you will be examined by a physician with x-rays measuring the amount of their scoliotic curve(s). The angle measurement is called a Cobb angle. X-rays are taken of the whole spine and in full weight-bearing. Curves are then measured to assess the Cobb angle.

Idiopathic scoliosis means the cause is unknown. It most common form of scoliosis. It rarely causes pain in children, and in most cases the curve is minor enough to be considered an asymmetry. 80-90% of structural scoliosis is idiopathic, 10-20% is from congenital abnormalities, neuromuscular or musculoskeletal conditions. There is no clear cause for adolescent idiopathic scoliosis and is generally believed to be multifactorial. Recently studies point to a genetic role in addition to other cause. 

Functional Scoliosis, also called degenerative scoliosis or adult onset scoliosis, has a prevalence of more than 8 % in adults over the age of 25 and rises up 68 % in the age of over 60 years due to degenerative changes in the aging spine. Functional scoliosis can be corrected by shift in posture, while structural is fixed deformity cannot be fully corrected.

Scoliosis has not been found in chimpanzees or gorillas. It has been hypothesized that scoliosis may be related to differences in humans vs apes. Apes have a shorter and less mobile lower spine than humans, and they have highly developed erector spinae muscles. Humans have a more mobile lower spine and pelvis, with less developed erector spinae. And, humans are bipedal. It is thought that these characteristics may differentiate the lack of scoliosis in primate.

According to the fossil record, earlier hominins, such as Australopithecus and H. erectus, may have exhibited an even greater prevalence of scoliosis as bipedal ability was first emerging. Fossil records indicate there may have been selection over time for a slight reduction in lumbar length compared to what we see today. This suggests that selection has favored a spine that can efficiently support walking with a lower risk of spinal disorders. The links between human spinal morphology, bipedality, and scoliosis suggest a link between these features and a potential evolutionary basis for the condition. And, this may explain why some people have an extra lumbar vertebra.

Epidemiology: Although scoliosis can occur earlier or later in development and even into adulthood, one study states the primary age of onset for scoliosisis 10-15 years old making up to 85% of those diagnosed.The risk of curvature progression increases during puberty when the growth rate of the body is the fastest. Scoliosis with significant curvature of the spine is much more prevalent in girls than in boys, and girls are eight times more likely to need treatment for scoliosis because they tend to have curves that have a greater probability of progression. The majority of all cases of scoliosis are mild.

Scoliosis affects 2–3% of the United States population, which is equivalent to about 5 to 9 million cases. Some studies say up to 5% depending on the population studied.

Incidence of idiopathic scoliosis (IS) stops after puberty when skeletal maturity is reached, however, further curvature may proceed during late adulthood due to vertebral osteoporosis and weakened musculature.

Want us to help you reduce symptoms and build strength due to your spinal asymmetry or scoliosis? Schedule an appointment with us today.

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