The Cobb angle is used to quantify the magnitude of spinal deformities, especially in the case of scoliosis.
To measurement of the Cobb angle, one must first decide which vertebrae are the end-vertebrae of the curve deformity (vertebrae at the upper and lower limits of the curve) and then Cobb angle formed by the intersection of two lines:
- one parallel to the endplate of the superior end vertebra and
- the other parallel to the endplate of the inferior end vertebra.
The angle may be plotted manually or digitally and scoliosis is defined as a lateral spinal curvature with a Cobb angle of 10° or more.
The Cobb angle was first described in 1948 by Dr. John R Cobb.