The sternocarpal process is a small bony protrusion at the lowermost end of the human sternal body. It is the smallest structure in the entire sternum and the most variable in the sternum. In adolescence, the sternocarpal process is a cartilaginous structure, and most of the protrusions of the sternocarpal process in adolescents are normal. This is because when adolescents are growing and developing, the rib cartilage and sternal cartilage are not yet fully developed. With the gradual completion of growth and development, the rib cartilage is gradually formed, and the saber cartilage is gradually partially ossified, and the body form, subcutaneous fat and chest muscles are gradually developed completely, then the symptoms of sternocarpal protrusion may disappear. In the case of adults, the protrusion of the sternocostal process is usually seen in people with a thin body posture or those who work a lot, and the protrusion of the sternocostal process is more obvious or is often stimulated by external forces.