Musculoskeletal System ORGAN SYSTEMS



Scoliosisis a lateral curvature of the spine. Adolescent idiopathic scoliosis is the most common type of scoliosis which typically has an onset after 10 years of age. | Scoliosis and the Cobb Angle: Jorge Muniz, PA-C


  • Idiopathic (M/C, 80%)


The degree of curvature of the spine is determined by the Cobb angle. A curve with a Cobb angle ≥ 10 degrees defines scoliosis. To determine the Cobb angle, begin by identifying the vertebrae at the upper and lower limits of the curve. Lines are then drawn extending along the outer vertebral borders. From these lines two more perpendicular lines are constructed. The Cobb angle is formed by the intersection of these lines.

Cobb angle measurement in scoliosis | Copyright (c) 2005, GNU Free Documentation License 1.2


Moderate curves (20 to 40 degrees) are treated conservatively with physical therapy and bracing. Severe curves greater than 40 degrees may require surgery.

Scoliosis patient in Chêneau brace correcting from 56° to 27° Cobb (primary correction of 52%). | Weiss HR. Scoliosis 2007, 2:19. PMID: 18163917. doi:10.1186/1748-7161-2-19., CC BY 2.0,

Preoperative (left) and postoperative (right) X-ray of a person with thoracic dextroscoliosis and lumbar levoscoliosis: The X-ray is usually projected such that the right side of the subject is on the right side of the image; i.e., the subject is viewed from the rear (see left image; the right image is seen from the front). This projection is typically used by spine surgeons, as it is how surgeons see their patients when they are on the operating table (in the prone position). This is the opposite of conventional chest X-ray, where the image is projected as if looking at the patient from the front. The surgery was a fusion with instrumentation.

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