The common reasons for the protrusion of the anterior thoracic bones are excessive thinness, old injury, and deformity of the thorax, as follows: 1, the patient is too thin: the more common reason is that the patient is too thin, resulting in some normal bony protrusion of the chest more obvious, such as in malnutrition, may lead to thinning of subcutaneous fat, thinning of the pectoral muscle, which will make the normal bony protrusion of the chest, like the saber protrusion, sternal angle, etc. become very obvious. 2.Old injury: Some patients have such a situation due to old injury here, such as old fracture of ribs or sternum, and there is deformity healing when recovering, the above symptoms may appear. 3.Deformity of thorax: Some patients have such a situation due to deformity of thorax, such as when patients have scoliosis or chicken chest, they may have the above symptoms.