The fourth intercostal space on the right edge of the sternum in men is usually where the nipple is located and is a simpler marker for positioning, while the nipple area on the left side is the fourth intercostal space on the left edge of the sternum, where the heart is located. In some patients with cardiac and respiratory arrest, the palm root can be placed on the left nipple area, the range of apical activity, for chest compressions when performing CPR. However, due to the development of the breast in women, it is more difficult to locate it. Usually, you can count down to the fourth or fifth intercostal space through the angle of the rib cage corresponding to the second intercostal space, and the fifth intercostal space at the left edge of the sternum, which is the more obvious part of the heartbeat point. This location is also a marker on the body surface. When male patients undergo cardiac auscultation to listen for heart sounds or heart rate, they can also place the stethoscope directly near the papillary area on the left side, i.e., the apical beating range. In this area the heart sounds can be clearly heard as well as the heart rate, whether the rhythm is uniform, whether there are associated additional heart sounds, or whether there is a heart murmur present.