Scoliosis, a lateral curvature of the spine, may be found in the thoracic, lumbar, or thoracolumbar spinal segment. The curve may be convex to the right (more common in thoracic curves) or to the left (more common in lumbar curves). Rotation of the vertebral column around its axis occurs and may cause rib cage deformity. Scoliosis is often associated with kyphosis (humpback) and lordosis (swayback).
Scoliosis may be functional or structural. Functional (postural) scoliosis usually results from poor posture or a discrepancy in leg lengths, not fixed deformity of the spinal column. In structural scoliosis, curvature results from a deformity of the vertebral bodies.
Structural scoliosis may be one of three types:
Congenital scoliosis is usually related to a congenital defect, such as wedge vertebrae, fused ribs or vertebrae, or hemivertebrae.
Paralytic or musculoskeletal scoliosis develops several months after asymmetrical paralysis of the trunk muscles from polio, cerebral palsy, or muscular dystrophy.
Idiopathic scoliosis (the most common form) may be transmitted as an autosomal dominant or multifactoral trait. This form appears in a previously straight spine during the growing years.
Idiopathic scoliosis can be classified as infantile, which affects mostly male infants between birth and age 3 and causes left thoracic and right lumbar curves; juvenile, which affects both sexes between ages 4 and 10 and causes varying types of curvature; or adolescent, which generally affects girls between age 10 and achievement of skeletal maturity and causes varying types of curvature.
Signs and symptoms
The most common curve in functional or structural scoliosis arises in the thoracic segment, with convexity to the right, and compensatory curves (S curves) in the cervical segment above and the lumbar segment below, both with convexity to the left. As the spine curves laterally, compensatory curves develop to maintain body balance and mark the deformity.
Scoliosis rarely produces subjective symptoms until it’s well established; when symptoms do occur, they include backache, fatigue, and dyspnea. Because many teenagers are shy about their bodies, their parents suspect that something is wrong only after they notice uneven hemlines, pant legs that appear unequal in length, or subtle physical signs like one hip appearing higher than the other.
Untreated scoliosis may result in pulmonary insufficiency (curvature may decrease lung capacity), back pain, degenerative arthritis of the spine, disk disease, and sciatica.
Anterior, posterior, and lateral spinal X-rays, taken with the patient standing upright and bending, confirm scoliosis and determine the degree of curvature (Cobb method) and flexibility of the spine. (See Cobb method for measuring angle of curvature.) A scoliometer can also be used to measure the angle of trunk rotation.