Welcome to the Haller Index Calculator! This tool helps you quickly determine the Haller Index, a key measurement used in assessing chest wall deformities such as pectus excavatum. By entering a few simple values, you can calculate the index and understand whether the chest shape falls within the normal range or indicates a more severe condition.
The calculator is easy to use—just input the transverse diameter and the anteroposterior diameter. You can start using it right away, or continue reading to learn about the formula, the meaning of its parameters, and see an example calculation.
Understanding the Formula
The formula for the Haller Index is:
Haller Index = A / B
Where:
- A = Transverse diameter (the horizontal distance between the innermost aspects of the ribs)
- B = Anteroposterior diameter (the shortest distance between the back of the sternum and the front of the vertebral body)
In simple terms, the Haller Index compares the chest’s width to its depth. A normal chest typically has a value around 2.5 or less, while values above 3.25 are often considered severe enough to recommend surgical evaluation.
Parameters Explained
Transverse Diameter (A): This is the chest’s width measured inside the rib cage. It is taken as the horizontal distance between the inner edges of the ribs.
Anteroposterior Diameter (B): This measures the depth of the chest. It is the shortest distance between the sternum (breastbone) and the spine.
Haller Index (A/B): The resulting ratio. A higher value indicates a flatter chest shape and may suggest the presence of pectus excavatum.
How to Use the Haller Index Calculator — Step-by-Step Example
Let’s go through an example:
- Suppose the transverse diameter (A) is 28 cm.
- The anteroposterior diameter (B) is 9 cm.
- Apply the formula:
Haller Index = A / B
Haller Index = 28 / 9
Haller Index ≈ 3.11
In this case, the Haller Index is 3.11, which suggests a moderate chest wall deformity that may require medical evaluation, depending on symptoms and clinical findings.
Additional Information
Here’s a quick reference for interpreting Haller Index values:
| Haller Index Value | Interpretation |
|---|---|
| ≤ 2.5 | Normal chest shape |
| 2.6 – 3.2 | Mild to moderate pectus excavatum |
| ≥ 3.25 | Severe pectus excavatum (surgical evaluation often recommended) |
FAQs
The Haller Index is used to quantify the severity of pectus excavatum, a condition where the chest wall is sunken inward.
A value of 3.25 or higher is typically considered severe enough to discuss surgical options with a healthcare provider.
No. Accurate measurement of the transverse and anteroposterior diameters usually requires CT scans or other imaging methods.