Pectus carinatum is a chest deformity characterized by a protrusion of the breastbone, or sternum, which causes the chest to appear more prominent. This condition can develop during childhood or adolescence and may be associated with growth spurts. It is often referred to as "pigeon chest" due to its distinctive shape. The exact cause of pectus carinatum is not fully understood, but it may involve genetic factors or abnormal growth of the rib cage. While it is usually not life-threatening, some individuals may experience discomfort or self-esteem issues. Treatment options include braces or, in severe cases, surgery.