How is scoliosis quantified on radiographs?

• A. Cobb angle measured between lines drawn parallel to the top endplate of the upper vertebra and the bottom endplate of the lower vertebra at the curve apex.
• B. Measured using the vertebral body heights.
• C. From posterior aspect of canal to vertebral body.
• D. Using a ratio of scoliosis to height.

Answer: (A)

Scoliosis on radiographs is quantified using the Cobb angle. Identify the end vertebrae at the curve’s ends, then draw lines parallel to the superior endplate of the upper vertebra and the inferior endplate of the lower vertebra. The angle formed by those lines is the Cobb angle, reported in degrees, and it’s the standard way to assess how severe the curvature is and to monitor progression over time. Other ideas listed don’t measure the lateral curvature: they reference vertebral body heights, distances within the spinal canal, or a height-based ratio, which don’t quantify scoliosis.