Abnormal spinal curvatures can result from disease, weakness,
or paralysis of the trunk muscles, poor posture, or congenital
defects in vertebral anatomy. The most common deformity is an abnormal
lateral curvature called scoliosis. It occurs most often in the thoracic
region, particularly among adolescent girls. It sometimes results
from a developmental abnormality in which the body and arch fail to
develop on one side of a vertebra. If the person’s skeletal growth is not
yet complete, scoliosis can be corrected with a back brace.
An exaggerated thoracic curvature is called kyphosis (hunchback,
in lay language). It is usually a result of osteoporosis, but it also
occurs in people with osteomalacia or spinal tuberculosis and in adolescent
boys who engage heavily in such spine-loading sports as
wrestling and weightlifting. An exaggerated lumbar curvature is
called lordosis (swayback, in lay language). It may have the same
causes as kyphosis, or it may result from added abdominal weight in
pregnancy or obesity.