Serous layer of pericardium

The serous pericardium is deep to the fibrous pericardium of the heart. It contains two layers, both of which function in lubricating the heart to prevent friction from occurring during heart activity:

• The layer adherent to the fibrous pericardium is the parietal serous pericardium.

• The layer that invests the heart and great vessels is the visceral serous pericardium. On the heart, this layer is known as the epicardium.

Together these two layers form a continuous uninterrupted membrane. Between these two layers exists a small cavity called the pericardial cavity, which contains a supply of serous fluid. The serous fluid that is found in this space is known as the pericardial fluid.