The lower margin of the heart extends from the sternal end of the right sixth costal cartilage to the apex in the fifth intercostal space near the midclavicular line.
Where to listen for heart sounds
To listen for valve sounds, position the stethoscope downstream from the flow of blood through the valves (Fig. 3.110).
The tricuspid valve is heard just to the left of the lower part of the sternum near the fifth intercostal space.