The pericardial cavity is formed by which two layers of the serous pericardium?

• A. Parietal layer of serous pericardium and visceral layer of serous pericardium
• B. Fibrous pericardium and parietal serous layer
• C. Endocardium and epicardium
• D. Myocardium and epicardium

Answer: (A)

The space that cushions the heart is created by the two layers of the serous pericardium. The outer layer lines the fibrous pericardium and is called the parietal serous layer, while the inner layer hugs the heart and is the visceral serous layer (often referred to as the epicardium when it covers the heart). The pericardial cavity lies between these two layers and contains a small amount of serous fluid to reduce friction as the heart beats. So, the cavity is formed by the parietal and visceral layers of the serous pericardium. Endocardium and epicardium, or myocardium and epicardium, are layers tied to the heart wall itself, not the cavity. The fibrous pericardium provides the tough outer coat, but the actual space of the cavity comes from the two serous layers.