The Cobb’s angle is an important measurement in diagnosing scoliosis and determining what kind of treatment is needed, if any at all. It is the measure of curvature of the spine affected by scoliosis.
To determine the Cobb’s angle of the spine, the vertebrae that is most displaced and rotated, with the least tilted end plates. This is known as the apical vertebrae. The end vertebrae above and below the apical vertebrae are identified next. These have minimum displacement and rotation, but are most tilted from its original position.
Cobb's Angle
After all of these are identified, a line is drawn parallel to the plates of the end vertebrae that are furthest away from the apical vertebrae. Next, two lines perpendicular to the first pair of lines are drawn towards each other until they intersect and form an angle. This is known as Cobb’s angle. Because this only measures scoliosis in one plane, this is not useful for spinal deformities in three dimensions. The picture to the right shows an example of an X-ray scan with lines drawn to determine the Cobb’s angle.
This measurement is used to determine what the best course of action for treatment is. In general, scoliosis is only diagnosed with an angle of curvature of at least 10 degrees. Anything between 10 – 20 degrees should be monitored regularly to see that it does not get worse. Between 20 – 40 degrees, a brace is most likely recommended. Over 40 degrees of curvature, scoliosis surgery is the best course of action.
To sum it all up, see the table below:
| Cobb’s Angle | Course of Action |
|---|---|
| Below 10 | Not Scoliosis |
| 10 – 20 | Regular Checkups |
| 20 – 40 | Body Brace |
| 40 and up | Scoliosis Surgery/Spinal Fusion |
