Enter the distance between the inner edges of the rib cage at the point of maximum deformity and the width of the chest at the same level into the calculator to determine the Haller Index. This calculator can also evaluate any of the variables given the others are known.

## Haller Index Formula

The following formula is used to calculate the Haller Index.

HI = D / W

Variables:

• HI is the Haller Index
• D is the distance between the inner edges of the rib cage at the point of maximum deformity (mm)
• W is the width of the chest at the same level (mm)

To calculate the Haller Index, divide the distance between the inner edges of the rib cage at the point of maximum deformity by the width of the chest at the same level. The result is the Haller Index, a measure of chest wall deformity.

## What is a Haller Index?

The Haller Index is a measurement used in radiology to determine the severity of pectus excavatum, a condition where the breastbone sinks into the chest. It is calculated by measuring the distance between the spine and the sternum, and dividing it by the width of the chest. A normal Haller Index is about 2.5, while an index of 3.25 or higher is typically considered severe and may require surgery.

## How to Calculate Haller Index?

The following steps outline how to calculate the Haller Index.

1. First, determine the distance between the inner edges of the rib cage at the point of maximum deformity (D) in millimeters (mm).
2. Next, determine the width of the chest at the same level (W) in millimeters (mm).
3. Next, gather the formula from above: HI = D / W.
4. Finally, calculate the Haller Index.
5. After inserting the values of D and W into the formula and calculating the result, check your answer with the calculator above.

Example Problem:

Use the following variables as an example problem to test your knowledge.

Distance between the inner edges of the rib cage at the point of maximum deformity (D) = 50 mm

Width of the chest at the same level (W) = 25 mm