Which serous membrane lines the diaphragm and sternum?

• A. Parietal Pericardium
• B. Visceral Pericardium
• C. Epicardium
• D. Serous Fluid

Answer: (A)

The key idea is how serous membranes line cavities and attach to surrounding structures. The parietal serous pericardium lines the pericardial cavity (the space around the heart) and is attached to the fibrous pericardium, which in turn anchors to the diaphragm and the sternum. That makes it the membrane that lines the area up to those bony and muscular borders of the thoracic cavity. The visceral pericardium, by contrast, covers the surface of the heart itself (the epicardium), not the diaphragm or sternum. Serous fluid is simply the lubricant between these layers, not a lining.