What Cobb-angle value defines scoliosis?

What Cobb-angle value defines scoliosis?

• A. 5 degrees
• B. 10 degrees or greater
• C. 0 degrees
• D. 15 degrees

Answer: (B)

The main idea is how scoliosis is defined using the Cobb angle. The Cobb angle measures the degree of spinal curvature on an X-ray by drawing lines along the endplates of the most tilted vertebrae at the top and bottom of the curve and measuring the angle between perpendiculars to those lines. Scoliosis is defined when this angle is 10 degrees or greater on a standing radiograph. This threshold distinguishes a true structural curve from normal spinal variations or asymmetry. A smaller angle, like 5 degrees, is below the diagnostic cutoff; zero degrees means no curvature; and while a 15-degree curve is certainly present, the defining criterion remains 10 degrees.

The main idea is how scoliosis is defined using the Cobb angle. The Cobb angle measures the degree of spinal curvature on an X-ray by drawing lines along the endplates of the most tilted vertebrae at the top and bottom of the curve and measuring the angle between perpendiculars to those lines. Scoliosis is defined when this angle is 10 degrees or greater on a standing radiograph. This threshold distinguishes a true structural curve from normal spinal variations or asymmetry. A smaller angle, like 5 degrees, is below the diagnostic cutoff; zero degrees means no curvature; and while a 15-degree curve is certainly present, the defining criterion remains 10 degrees.