Triple Cobb Angle: How to perform

Last updated on July 6 2022

Description

Cobb angle is a measurement used for the evaluation of curves in scoliosis on an AP radiographic projection of the spine.

The Cobb Angle measures the angle between the vertebrae of the curve deformity (scoliosis) that have the end plates with the maximum slope. In S-shaped scoliosis (double curve), there are two contiguous curves, the lower-end vertebra of the upper curve represents the upper-end vertebra of the lower curve. Although rare, three-curved scoliosis may occur. The image of the spine must be in the AP view. Scoliosis is defined as a lateral spinal curvature with a Cobb angle of 10° or more.

Measurements

The measurement made by the procedure is displayed in the image:

• Superior Triple Cobb Angle (STCA): the angle between the superior line and the first medium line.
• Medium Triple Cobb Angle (MTCA): the angle between the first medium line and the second medium line.
• Inferior Triple Cobb Angle (ITCA): the angle between the second medium line and the inferior line.

Auxiliary references 

To show this procedure, PeekMed® needs additional references:

• Superior Line: a line passing through the upper and lower side of the superior vertebrae of the first curve that has the end plate with the maximum slope;
• First Medium Line: a line passing through the upper and lower side of the inferior vertebrae of the first curve that has the end plate with the maximum slope;
• Second Medium Line: a line passing through the upper and lower side of the inferior vertebrae of the second curve that has the end plate with the maximum slope;
• Inferior Line: a line passing through the upper and lower side of the inferior vertebrae of the third curve that has the end plate with the maximum slope.