Pericardium (definition of)

The pericardium is the name of the mesothelial layer surrounding the heart muscle as well as the aorta, pulmonary artery, and other major arteries. It consists of two primary membranes: the outer membrane or parietal pericardium and the inner visceral pericardium. The latter surrounds the heart itself, with the outer membrane separating the heart mechanism from the rest of the chest cavity, attaching to the diaphragm and the rear of the sternum (breastbone). Between these two layers, the lymphatic system pumps a lubricative fluid that allows the heart to beat. Pericardial mesothelioma, is a type of cancer that originates in the mesothelium and is known only to be caused by asbestos exposure. Physicians believe that asbestos fibers are inhaled and absorbed into the bloodstream and become entangled in the heart's lining as the blood processes through the heart. Learn more about pericardial mesothelioma.