The pericardium consists of an outer fibrous layer and an inner serous layer. The serous layer covers the surface of the heart and the proximal portion of the large vessels (visceral pericardium), folds back on itself, and lines the fibrous layer (parietal pericardium). Normal pericardial thickness is less than or equal to 2 mm. The space between the visceral and the parietal layer forms the pericardial cavity, which normally contains 10 to 50 mL of fluid. The pericardium lubricates and reduces friction, serves as a barrier against infection, maintains the heart in a relatively stable position within the thoracic cavity, and prevents acute distention of the cardiac chambers. None of these functions, however, is essential for life, and the pericardium may, in fact, be absent at birth.
This review contains 16 figures, 1 table, and 50 references.
Key Words: Pericardium, parietal pericardium, visceral pericardium