The heart is located in the left thoracic cavity, the nipple is located on top of the right and left pectoralis major muscles, and the left nipple is adjacent to the heart in the following positional relationship: The heart is located in the thoracic cavity behind the left breast, between the 2nd and 5th ribs, and the nipple is located over the right and left pectoralis major muscles, between the 2nd and 6th ribs, with the approximate location of the heart 1-2 centimeters to the right behind the left nipple. The location of the apical beat is 0.5 to 1 cm medial to the 5th intercostal space in the left midclavicular line, to the lower right of the nipple; the edge of the base of the heart is at the 2nd intercostal space at the left edge of the sternum, to the upper right of the nipple. If pain in the precordial region occurs, it is best to go to the hospital, under the guidance of the doctor to do ultrasound combined with electrocardiogram and related tests to clarify the cause.