Pectus excavatum is a congenital condition where the breastbone, or sternum, is sunken into the chest, creating a hollowed appearance. This condition can vary in severity and may affect the heart and lungs, potentially leading to breathing difficulties or reduced exercise tolerance in some individuals. The exact cause of pectus excavatum is not fully understood, but it is believed to involve abnormal growth of the rib cage during development. Treatment options range from monitoring mild cases to surgical procedures for more severe cases, aimed at improving both function and appearance.