Precordium vs Pericardium. The "precordium" refers to the area on the chest wall directly over the heart, essentially the visible part of the chest where you can access the heart sounds, while the "pericardium" is the sac-like membrane that completely surrounds the heart, acting as a protective covering and providing lubrication for its movement; in simpler terms, the precordium is the chest region where you can examine the heart, while the pericardium is the actual protective layer around the h