Sternal defects are congenital conditions where the sternum, or breastbone, does not form properly during fetal development. These defects can vary in severity and may include conditions like pectus excavatum, where the sternum is sunken inward, or pectus carinatum, where it protrudes outward. These abnormalities can affect the chest's shape and may lead to respiratory or cardiac issues in some cases. Treatment options depend on the severity and can range from monitoring to surgical intervention, aiming to improve both function and appearance.