What defines pectus carinatum?

Pectus carinatum, often referred to as "pigeon chest," is characterized by an anterior protrusion of the sternum. This deformity occurs when the cartilages connecting the ribs to the sternum develop abnormally, causing the sternum to bow outward rather than lie flat. This protrusion can lead to cosmetic concerns and sometimes to respiratory difficulties due to the altered mechanics of the chest wall.

Understanding this condition is crucial in clinical practice, as it may affect not only appearance but also function, particularly if the protrusion is significant. It's important to recognize that other choices refer to different conditions or anatomical features that do not describe pectus carinatum, further emphasizing the specificity of the correct answer.