Pectus carinatum is an uncommon birth defect in which a child's breastbone protrudes outward abnormally. Sometimes the deformity isn't noticeable until after the adolescent growth spurt.
For most children and teens, the main issue with pectus carinatum is the way it looks. However, some will also have problems with shortness of breath, especially during exercise.
While surgical repair is an option for people with severe pectus carinatum, the use of a brace to help flatten the chest is the preferred treatment for children whose bones are still growing. The brace is worn up to 23 hours a day, and results can begin to be seen in just a few months.
Pectus carinatum care at Mayo Clinic