Sternal protrusion may be related to the following reasons: 1. It may be a normal bony sign, if the patient is thin and has thin subcutaneous fat, then some normal bony signs will look very obvious on the body surface, such as sternal angle on the upper part and saber protrusion on the lower part, which are normal and physiological, not pathological. 2. This condition may be caused by chicken chest, if The patient has malnutrition during the growth period, will produce rickets, after which will show a deformity such as chicken chest. The main manifestation is the protrusion of the sternum, and the anterior and posterior diameter of the thorax is relatively larger than normal, that is, the chest is more forward protrusion. 3, this situation may be caused by old injury to the sternum, such as a previous fracture of the sternum, then after recovery, there may be excessive osteophytes left here, which leads to local protrusion. 4, this situation may be caused by scoliosis, in The onset of severe scoliosis may be accompanied by a severe deformity of the thorax, followed by a protrusion at the sternum.