Pulmonary valve is surface marked at the sternal end of the left 3rd costal cartilage. Aortic valve is surface marked at the sternal margin of the left 3rd intercostal space. Mitral valve is surface marked at the sternal margin of the 4rd left costal cartilage. Tricuspid valve is surface marked at the midsternum opposite  the 4th intercostal space, however, it is to be noted that the actual position of the valves does not coincide with the auscultatory areas.

The auscultatory areas are as follows:

Pulmonary valve is best heard at the left second intercostal space near the sternum. 

Aortic auscultatory area is at the right second intercostal space near the sternum.

Mitral auscultatory area is just over the apex of the heart.

Tricuspid auscultatory area is at the lower end of the body of the sternum.  

The auscultatory areas are the sites where the closure of valves are best heard.