Which structure surrounds, anchors, and protects the heart?

• A. Pericardium
• B. Endocardium
• C. Myocardium
• D. Aorta

Answer: (A)

The pericardium surrounds, anchors, and protects the heart. It’s a double-walled sac: the tough outer fibrous layer attaches the heart to the diaphragm and sternum, helping keep the heart in place; the inner serous layer forms a parietal layer that lines the fibrous sac and a visceral layer that covers the heart itself, with a small amount of pericardial fluid in between to reduce friction during beating. This setup protects the heart from trauma, prevents overexpansion, and keeps it properly positioned in the chest. The other structures do not fit this role: the endocardium lines the inside of the heart chambers, the myocardium is the muscular wall that contracts to pump blood, and the aorta is a major artery leaving the heart.