The protrusion of the bones below the clavicle is caused by the following reasons: 1. it is caused by the patient being too thin, if the patient is thin and has thin chest muscles, when the patient raises his chest, he will obviously see the ribs below the clavicle and can see the gap between the ribs. 2. it may be caused by a thoracic deformity, if the patient has a scoliosis of this kind, it will cause one side of the thorax to produce A very obvious deformity. 3.It may be caused by internal lesions of the thoracic cavity, such as chronic obstructive pulmonary disease or massive pleural effusion, which may make the thorax look more pronounced and the rib gap wider, showing that the bones under the clavicle are more prominent. 4.It may also be caused by malnutrition-related diseases, such as rickets. In the case of rickets, for example, the bones below the clavicle may protrude due to the presence of a chicken chest and rib cage beads.