Pericardium
The
pericardium is the membrane that surrounds the heart, as well as the roots of the primary blood vessels (the aorta, pulmonary artery, etc.) (1, 2). It is composed of two primary membranes: the outer membrane (parietal pericardium) loosely surrounds the heart and is attached to the central part of the diaphragm and the back of the breastbone. The inner membrane (visceral pericardium or epicardium) is a double membrane, with one layer closing enveloping the heart and the other layer above it, attached to the inner surface of the perietal pericardium. The space between the two primary layers of the pericardium (pericardial space) is filled with pericardial fluid. This small amount of fluid acts as a lubricant that facilitates the normal movement of the heart within the chest (1).