Pectus carinatum, sometimes called “pigeon chest,” is an uncommon chest wall deformity, but it’s not extremely rare. It occurs two to four times less frequently than pectus excavatum (the more familiar sunken chest), and pectus excavatum itself accounts for 65 to 95% of all chest wall deformities. Exact population-level numbers are hard to pin down because pectus carinatum often isn’t noticed until the teenage years, meaning many mild cases go uncounted.
How It Compares to Other Chest Wall Conditions
Pectus excavatum affects roughly 1 in every 300 to 400 people, making it the most common chest wall deformity by a wide margin. Pectus carinatum is the second most common, but it shows up two to four times less often. That puts the ballpark estimate somewhere around 1 in 1,000 to 1 in 1,500 people, though published estimates vary because the condition is often underdiagnosed.
The reason for underdiagnosis is timing. Unlike pectus excavatum, which is frequently spotted in infancy, pectus carinatum typically becomes visible during puberty, when the chest is growing rapidly. It can appear as early as age 10, with the peak around age 16 in females and 18 in males. A mild case in a younger child may go completely unnoticed until a growth spurt makes the protrusion obvious.
Who Gets It
Boys are affected far more often than girls, at a ratio of about 4 to 1. The condition also runs in families, though the exact inheritance pattern isn’t fully understood. If a parent or sibling has any type of chest wall deformity, the likelihood goes up.
About 5.3% of people who present with a pectus deformity (either carinatum or excavatum) turn out to have Marfan syndrome, a connective tissue disorder. That’s roughly 17 times higher than the rate of Marfan syndrome in the general population (about 0.3%). The overlap is even more pronounced in people who have a combination deformity, where the chest is sunken in one area and protruding in another. In that group, the Marfan rate reaches 20%. This is why doctors will sometimes screen for connective tissue conditions when pectus carinatum is diagnosed.
Does It Affect Breathing or Heart Function?
One of the first questions people have after learning about pectus carinatum is whether a protruding breastbone causes real health problems or is purely cosmetic. The research is reassuring for most cases. A study published in BMJ Open Respiratory Research tested lung function in 46 adolescents with pectus carinatum and found their airflow measurements were essentially normal. Forced lung capacity, the volume of air you can blow out in one second, and overall lung size all fell within expected ranges.
Heart function tells a slightly more nuanced story. The same study found that resting cardiac measurements were technically within normal limits, but a notable subset of patients had values at the lower edge. About 26% had right-side heart pumping efficiency below the lower limit of normal, and roughly 9 to 13% showed the same pattern on the left side. None of these reached dangerously low levels, but the findings suggest that moderate to severe cases may warrant cardiac screening. Some patients with more pronounced deformities do report feeling short of breath during exercise, and those symptoms sometimes improve after surgical correction.
How Severity Is Measured
Doctors use CT imaging to calculate what’s called the Haller index, a ratio of chest width to chest depth. For pectus carinatum, a lower number means a more severe protrusion (the opposite of pectus excavatum, where a higher number signals worse severity). Patients who eventually need surgical correction have an average Haller index of about 1.8. Most people with pectus carinatum fall on the mild end of the spectrum and never need surgery.
Treatment and Success Rates
The first-line treatment for pectus carinatum in growing teenagers is a compressive brace, a device worn over the chest that applies gentle, steady pressure to gradually flatten the protrusion. In a study of 767 pediatric patients followed over nine years, bracing achieved a satisfactory chest appearance in 84% of cases. The average treatment time was six months to a year, with younger patients responding faster. After the chest flattens, most doctors recommend continuing to wear the brace for an additional two to three months to prevent the deformity from returning.
Older teenagers and those whose bones have stiffened may need longer bracing periods, and a small percentage don’t respond to bracing at all. For moderate to severe cases that fail conservative treatment, surgical correction is an option. The procedures involve either reshaping the cartilage directly or using an internal bar to reposition the breastbone, similar to techniques used for pectus excavatum but modified for the outward deformity.
The Psychological Side
Even though pectus carinatum rarely causes serious physical limitations, the cosmetic impact during adolescence can be significant. Teenagers may avoid swimming, changing in locker rooms, or wearing fitted clothing. Studies on pectus deformities consistently show that body image concerns and social anxiety are the primary reasons families seek treatment, more so than physical symptoms. The high success rate of bracing means most teens who pursue treatment end up with a chest shape they’re comfortable with, without needing surgery.