How to Measure Pectus Excavatum at Home

You can track pectus excavatum at home by measuring external chest depth, the distance the breastbone sits below the surrounding chest, and by taking standardised photographs over time. What you cannot produce at home is a Haller index or a correction index. Both require a cross-sectional scan of the chest, not a ruler.

Key points

  • The two numbers clinicians use to grade pectus excavatum, the Haller index and the correction index, are both taken from a cross-sectional image such as a CT or MRI, not from anything you can measure on the skin (St. Peter and colleagues, Annals of Thoracic Surgery).
  • In a chest without pectus excavatum the Haller index sits around 2.5. It is commonly banded below 3.2 mild, 3.2 to 3.5 moderate and above 3.5 severe, with 3.25 the long-standing surgical threshold (St. Peter and colleagues).
  • A correction index of 28% or more corresponds to that same threshold and stays accurate in non-standard chest shapes, while the Haller index overlaps by roughly 48% between people with and without the condition regardless of age (St. Peter and colleagues).
  • What you can reliably track at home is external depth and appearance, the same external depth that Luo and colleagues (2022, n=139) measured with a three-dimensional scanner to a residual depth under 3 mm.
  • Measure in the morning, before any vacuum bell session, because the post-session lift is temporary and partially reverses within hours (Haecker 2016).
  • No validated home-measurement protocol exists, and after 20 years of clinical use no validated guidelines for the therapy exist either (Haecker and colleagues 2024).

The short answer, expanded

Pectus excavatum is measured in two different worlds, and it helps to keep them separate. In the clinic, severity is a ratio taken from a cross-sectional scan of the chest. At home, all you have access to is the outside of the chest wall: how deep the hollow is and how it looks. These are not the same measurement, and treating a home reading as a clinical grade is the most common mistake people make when they start tracking their own chest.

That does not make home measurement pointless. It makes it a progress tool rather than a diagnostic one. A ruler cannot tell you your Haller index and it does not move the sternum, but a consistent home method will tell you whether the hollow is getting shallower over months of treatment, which is the question most people are actually asking. The rest of this article covers what the clinical numbers mean, what you can and cannot reproduce at home, and how to take a home measurement that is worth comparing to itself later.

What the evidence actually shows

What a clinician actually measures

The two numbers used to grade pectus excavatum both come from a single cross-sectional slice through the chest, usually a CT or MRI, and occasionally a low-dose or radiation-free alternative. St. Peter and colleagues, writing in the Annals of Thoracic Surgery, set out how both are calculated and why one is more reliable than the other. Knowing what they measure tells you precisely what a home reading can stand in for and what it cannot.

The Haller index and its severity bands

St. Peter and colleagues describe the Haller index as the inside transverse width of the chest divided by the front-to-back distance at the deepest part of the depression. In a chest without pectus excavatum that ratio sits around 2.5. The commonly used bands are below 3.2 for mild, 3.2 to 3.5 for moderate and above 3.5 for severe, and 3.25 has long served as the surgical threshold. Every one of those figures depends on the inside width of the ribcage, which is why the index cannot be produced without an image.

The correction index, and why it is steadier

St. Peter and colleagues found that the Haller index overlaps by roughly 48% between people with and without pectus excavatum, which means the two groups blur together at the edges regardless of age. The correction index was designed to separate them more cleanly. St. Peter and colleagues report that a correction index of 28% or more corresponds to the same 3.25 surgical threshold and stays accurate across ages and in non-standard chest shapes, where the Haller index can mislead. This is the more robust of the two clinical measures, and it is still an imaging measurement.

What this leaves for home measurement

None of those numbers can be reproduced with a tape measure, because all of them depend on the inside width of the ribcage that only imaging shows. What is left for home use is external depth, the vertical distance from a straight edge laid across the chest down to the deepest part of the hollow, plus standardised photographs. Published cohorts grade outcomes by change in Haller index on imaging, and Luo and colleagues (2022, n=139) tracked preschool children with a three-dimensional surface scanner to a residual depth under 3 mm. Both measured change over time with instruments you do not have at home. A ruler tracks the same external dimension with far less precision, which makes it useful for watching your own trend and unsuitable as a diagnosis.

Who this works best for

A home measurement earns its place in a specific set of situations.

  • Anyone already in treatment who wants to see a trend. A consistent monthly depth reading and a fixed set of photographs answer the practical question, is the hollow getting shallower, far better than memory or a mirror.
  • People deciding whether to seek an assessment. A rough external depth and a clear lateral photograph give a clinician something concrete to react to and can help you judge whether the change since last year is real.
  • Flexible, shallower chests. Shallower initial depth independently predicted complete correction in the preschool cohort (Luo and colleagues 2022, n=139), and shallower hollows are also the ones a home method tracks most accurately.
  • People who can keep the conditions constant. Same time of day, same posture, same landmarks. The method is only as good as its repeatability.

Who this does not work for

Home measurement is the wrong tool for several groups, and pretending otherwise causes real harm.

  • Anyone who needs a diagnosis or a severity grade. The Haller index and the correction index cannot be calculated from the skin surface, because both need the inside width of the chest (St. Peter and colleagues). A home number is a trend line, not a grade.
  • Asymmetric or rotated chests. Where the depression is off-centre or the sternum is twisted, a single depth reading taken at one spot can move a lot with small changes in position and will mislead you about progress.
  • Anyone with symptoms. Breathlessness out of proportion to exertion, palpitations, chest pain or reduced exercise tolerance are reasons to be assessed by a physician, not to reach for a ruler. Those symptoms change the decision and should come before any measurement or purchase.
  • People who measure straight after a session. The post-session lift is temporary and partially reverses within hours (Haecker 2016). Measuring then records a flattering number that will not hold.

What this means in practice

A home measurement is worth taking only if it is repeatable. Four things make it so.

Measure external depth with a straight edge and a ruler. Lie on your back so the chest is level. Rest a rigid straight edge across the chest so it bridges the hollow and touches the raised areas on either side. Measure straight down from the underside of the edge to the deepest part of the depression, and record the figure in millimetres. Mark the exact spot so you return to it next time.

Standardise your photographs. Take a front view and a side view in the same spot, same distance, same light, standing relaxed with your arms at your sides. The side view carries the most information, because depth is what changes. Date every set.

Measure in the morning, before the first session. The lift a vacuum bell produces is temporary and partially reverses within hours (Haecker 2016), so a reading taken at least 20 hours after the previous session, before the day's first, is the one that reflects durable change rather than the session you just finished.

Compare across months, not days. This therapy is measured in years. Luo and colleagues (2022, n=139) tracked change to a residual depth under 3 mm over a treatment period that independently predicted correction, and across the literature the strongest results come from patients who use the device consistently. Week-to-week noise will only discourage you. A single well-taken reading every month, compared over a year, is the signal.

Not sure whether this applies to you?

The two questions this article cannot answer for you are whether your own chest is a reasonable candidate, and which device size fits it. Both depend on measurements only you can take.

The FormaChest assessment takes about four minutes. It screens your situation against the variables the research identifies as predictive (age, depth of the indentation, chest flexibility and symptoms) and returns an honest read on whether conservative treatment is a reasonable first step. That includes telling you when the answer is to see a surgeon first, which it does for roughly the situations described in the section above.

It also returns a vacuum bell size recommendation based on your own measurements, at no cost.

Sizing is normally not free or simple in this category. The usual process is to email photographs of your bare chest to a company and wait for a reply, or to print paper templates and tape them to yourself, with the manufacturer warning that self-measurement may produce the wrong model. The assessment asks for numbers you can take alone with a ruler. No photographs, no email exchange, no deposit.

Take the free assessment →

What the research does not tell us

Anyone measuring at home should know where the evidence runs out.

There is no validated home-measurement protocol. The severity bands come from imaging indices (St. Peter and colleagues), and no published standard maps a home depth in millimetres onto mild, moderate or severe. Your reading tells you your own direction of travel; it does not place you on the clinical scale.

No validated treatment guidelines exist at all. After 20 years of clinical use, Haecker and colleagues (2024) state plainly that vacuum bell therapy has no validated guidelines, which includes how progress should be measured and how much change counts as success.

External depth is not what makes the condition matter clinically. The concern in significant pectus excavatum is how far the sternum presses toward the heart and lungs inside the chest, which a surface measurement cannot see. A shallow-looking hollow and a clinically significant one are not always the same thing.

The link between external change and index change is not established. No study cited here tells you how many millimetres of surface improvement equal a given fall in the Haller or correction index, so a home number cannot be converted into a clinical one.

About this guide This article is published by FormaChest, a European manufacturer of vacuum bell correction systems, registered in Romania as AUGUMENTUM SRL. We make the device described above, and every figure quoted is cited to its source so you can verify it independently. The reason home measurement matters to us is practical: a vacuum bell has to be sized to your chest, and the wrong size wastes the therapy. FormaChest ships the bell, brace and gel together rather than a device alone: the vacuum bell, a chest support brace, post-session skin care, the written protocol and scheduled follow-up. As a set, the bell, brace and gel are $461.40 in the men's line and $491.40 in the women's line, where every competitor in this category sells the device by itself. See what is included →Tomas Titus is the founder of FormaChest (AUGUMENTUM SRL, Craiova, Romania). He had pectus excavatum and corrected it without surgery, documenting his own vacuum bell treatment on camera, taking each depth measurement before a session rather than after. His chest depth went from 25mm to 4mm. That is one person's result at 19; published adult timelines run 12 to 24 months and results vary. He is not a clinician, and nothing in this article is a substitute for assessment by one.

Related questions

References

  1. St. Peter SD, Juang D, Garey CL, et al. A novel measure for pectus excavatum: the correction index. Annals of Thoracic Surgery.
  2. Scaife ER, et al. Vacuum bell therapy for pectus excavatum. 2025. n=240
  3. Luo D, Cheng K, Yuan M, Xu C, He T. Efficacy and determinants of vacuum bell treatment in preschool children with pectus excavatum. Frontiers in Pediatrics. 2022. PMID 36313864
  4. Haecker FM. Vacuum bell therapy. Annals of Cardiothoracic Surgery. 2016. PMID 27747177
  5. Haecker FM, et al. 20 years clinical application of the vacuum bell for conservative treatment of pectus excavatum. Journal of Thoracic Disease. 2024. PMID 39268139

This article is for information only and is not medical advice. Pectus excavatum should be diagnosed and assessed by a qualified physician. If you have chest pain, breathlessness, palpitations or reduced exercise tolerance, seek medical assessment before beginning any treatment.

Last reviewed: July 2026.

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