My Baby's Breastbone Sticks Out (Pectus Carinatum)
Medically reviewed by Dr. Sarah Chen, MD, FAAP · Board-Certified Pediatrician
Content reviewed against published AAP, NIH, CDC guidelines
Last reviewed:
Your baby's physical development is unique, and concerns about breastbone sticks out (pectus carinatum), here is what you need to know.
The short answer
Pectus carinatum (protruding breastbone or "pigeon chest") is less common than pectus excavatum. In babies and toddlers, a slightly prominent sternum is often normal. True pectus carinatum typically becomes more noticeable during adolescent growth spurts. If present in infancy, your pediatrician should monitor it.
Key takeaways
- Pectus carinatum (protruding breastbone or "pigeon chest") is less common than pectus excavatum. In babies and toddlers, a slightly prominent sternum is often normal. True pectus carinatum typically becomes more noticeable during adolescent growth spurts. If present in infancy, your pediatrician should monitor it.
- Usually normal when: Mild sternal prominence in a thin baby.
- Call your doctor if: Chest wall deformity with breathing difficulty.
- Varies by age — see the age-by-age breakdown below
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What Parents Should Know
According to AAP, NIH, CDC guidelines, pectus carinatum (protruding breastbone or "pigeon chest") is less common than pectus excavatum. In babies and toddlers, a slightly prominent sternum is often normal. True pectus carinatum typically becomes more noticeable during adolescent growth spurts. If present in infancy, your pediatrician should monitor it. At 0-12 months, a slightly prominent sternum in babies is common and usually normal. The thin chest wall makes bony structures more visible. Your pediatrician can evaluate whether the prominence is within normal range. It is generally considered normal when mild sternal prominence in a thin baby. However, you should contact your pediatrician promptly if chest wall deformity with breathing difficulty.
Normal vs. Concerning
By Age
What to expect by age
0-12 months
A slightly prominent sternum in babies is common and usually normal. The thin chest wall makes bony structures more visible. Your pediatrician can evaluate whether the prominence is within normal range.
12-24 months
If the prominence is stable and your child has no breathing or activity problems, monitoring at well visits is sufficient. In toddlers, pectus carinatum is rarely significant.
2-5 years
Pectus carinatum may become more noticeable with growth. If it is progressive or your child has other skeletal differences, evaluation by a pediatric surgeon may be recommended.
5+ years
Pectus carinatum typically becomes most prominent during the adolescent growth spurt. Bracing is the most common non-surgical treatment for cosmetically significant cases.
What to Tell Your Pediatrician
- Describe when you first noticed breastbone sticks out (pectus carinatum) and how it has changed over time.
- Note your baby's current age and which age-specific patterns you are seeing.
- Mention if prominence is increasing.
- Mention if your child has chest pain or breathing concerns.
- Let your doctor know if you have noticed any related concerns, such as changes in feeding, sleep, or movement patterns.
- Bring a list of any questions or observations you want to discuss at the appointment.
What Should You Do?
When to take action
- Mild sternal prominence in a thin baby.
- No breathing problems.
- Prominence is stable.
- Normal growth and development.
- Prominence is increasing.
- Your child has chest pain or breathing concerns.
- Other skeletal abnormalities are present.
- Chest wall deformity with breathing difficulty.
- Rapid change in chest wall shape.
What You Can Do at Home
- Keep track of when you notice breastbone sticks out (pectus carinatum) — noting the time of day, duration, and any triggers can help your pediatrician.
- Remember that mild sternal prominence in a thin baby — this is generally within the range of normal.
- At 0-12 months, focus on observation rather than intervention unless your pediatrician advises otherwise.
- Provide plenty of supervised floor time and tummy time to support your baby's physical development.
- While monitoring at home, seek immediate care if chest wall deformity with breathing difficulty.
Related Conditions
My Baby Has a Sunken Chest (Pectus Excavatum)
Pectus excavatum (sunken chest) is the most common chest wall deformity, affecting about 1 in 300-400 births. Mild cases are typically cosmetic and do not affect heart or lung function. It may become more noticeable with growth. Most cases do not need treatment, but your pediatrician should monitor it.
My Baby's Ribs Stick Out
Mild rib flaring (lower ribs that protrude slightly) is common in babies and toddlers, especially when lying down or with their arms up. It is often a normal anatomical variation, particularly in lean babies. However, significant rib flaring can sometimes indicate rickets (vitamin D deficiency) or core muscle weakness.
Related Resources
Milestone Checklists by Age
Track your baby's developmental milestones from birth to 5 years with age-specific checklists.
Month-by-Month Development
Detailed monthly development guides from birth through 24 months.
When to Call the Doctor
General guide on when to call the pediatrician, visit urgent care, or go to the ER.
Frequently asked questions
Is breastbone sticks out (pectus carinatum) normal?
When should I call the doctor about breastbone sticks out (pectus carinatum)?
When is breastbone sticks out (pectus carinatum) normal?
What causes breastbone sticks out (pectus carinatum)?
What should I mention to my pediatrician about breastbone sticks out (pectus carinatum)?
Is breastbone sticks out (pectus carinatum) normal at 0-12 months?
Is breastbone sticks out (pectus carinatum) normal at 12-24 months?
Should I go to the ER for breastbone sticks out (pectus carinatum)?
Does breastbone sticks out (pectus carinatum) go away on its own?
References
Doctor Visit Checklist
Bring this checklist to your next pediatrician visit to discuss My Baby's Breastbone Sticks Out (Pectus Carinatum).
Things to mention
- Describe when you first noticed breastbone sticks out (pectus carinatum) and how it has changed over time.
- Note your baby's current age and which age-specific patterns you are seeing.
- Mention if prominence is increasing.
- Mention if your child has chest pain or breathing concerns.
- Let your doctor know if you have noticed any related concerns, such as changes in feeding, sleep, or movement patterns.
- Bring a list of any questions or observations you want to discuss at the appointment.
Observations to share
- Prominence is increasing.
- Your child has chest pain or breathing concerns.
- Other skeletal abnormalities are present.
Urgent signs to report immediately
- Chest wall deformity with breathing difficulty.
- Rapid change in chest wall shape.
My notes
From ismybabyalright.com — free, evidence-based baby health guides
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Related Resources
Bottom line
Most cases of breastbone sticks out (pectus carinatum) are normal. Talk to your pediatrician if chest wall deformity with breathing difficulty.
Trust your instincts. If something feels wrong, reach out to your pediatrician. Worrying about your baby means you care — that is a good thing.
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Related Physical Concerns
My Baby Has a Sunken Chest (Pectus Excavatum)
Pectus excavatum (sunken chest) is the most common chest wall deformity, affecting about 1 in 300-400 births. Mild cases are typically cosmetic and do not affect heart or lung function. It may become more noticeable with growth. Most cases do not need treatment, but your pediatrician should monitor it.
My Baby's Ribs Stick Out
Mild rib flaring (lower ribs that protrude slightly) is common in babies and toddlers, especially when lying down or with their arms up. It is often a normal anatomical variation, particularly in lean babies. However, significant rib flaring can sometimes indicate rickets (vitamin D deficiency) or core muscle weakness.
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