The sternal angle is very important to all clinicians, this part is an important bony landmark of the chest, this is a very important signpost of the chest, only through this part can other corresponding anatomical landmarks be identified, and then guide the clinician in his work to do the corresponding physical examination, the corresponding operation. Therefore, the significance of this area is to guide the physician in the diagnosis and treatment of the condition, for example, by touching this area to the left and right, you can touch the second rib, and below the second rib is the second rib space. Because the first rib is often covered by the clavicle and is basically not palpable on the body surface, the second intercostal space can only be determined by touching the sternal angle and then locating the second rib. This intercostal space is very important for clinical examination and treatment. For example, the second intercostal space on the left and right edges of the sternum is the aortic auscultation zone and pulmonary artery auscultation zone of the heart, which means that the heart is auscultated with a stethoscope in this area when the relevant valves are auscultated. In addition, the second intercostal space on the left and right side, which intersects with the midclavicular line, is the site for chest puncture and closed chest drainage for tension pneumothorax. Therefore, only by determining the rib space here through the sternal angle can the site for puncture and drainage be determined. In addition, for clinical operation, the sternal angle is also needed for the corresponding positioning.