Pectus Carinatum Breast augmentation Surgery I have personally analyzed statistically that there are about 12~16% of those with Pigeon chest. This is rather a common form of chest cage. Pigeon chest is when the chest cage is roundly shaped by ribs, and breastbones. We call pigeon chest medically pectus carinatum. The shape is formed because costal cartilage and breastbone stick outwards. A bad...