Sternum protrusion generally refers to the abnormal protrusion of the sternum to the front, commonly seen in costochondritis, rickets, congenital chicken breast, but also seen in sternum fracture or thinner normal people. 1. Costochondritis: the swelling and enlargement of the rib cartilage near the sternum can be manifested as protruding sternum. 2. Rickets: Vitamin D deficiency, abnormal vitamin D metabolism and abnormal action lead to the insufficient calcification of the sternum and the rib cartilage, and the imbalance of the growth of the rib cartilage appearing as the protrusion of the sternum. 3. Congenital chicken breast: congenital developmental abnormality due to genetic reasons, chest wall deformity, sternum protrusion. 4. Sternum fracture: the broken end of the sternum fracture is not healed abnormally, and the sternum can also be protruded. 5. Thin normal people: normal people’s sternum is convex in the front and concave in the back, the sternal angle is elevated in the sternum, and the raphe can be slightly protruded forward, if the patient is thin, it can be manifested as protruding sternum. If the patient is thin, it can be manifested as protruding sternum. It is recommended to go to the hospital for further counseling or diagnosis and treatment.