What is the peritoneal cavity?

• A. Space between parietal and visceral peritoneum
• B. Double-layered membrane surrounding abdominal organs
• C. Space within the liver
• D. Membrane lining the stomach

Answer: (A)

The peritoneal cavity is the potential space between the two layers of the peritoneum—the parietal peritoneum lining the abdominal wall and the visceral peritoneum covering the abdominal organs. This space forms a closed sac inside the abdomen and normally contains a small amount of lubricating serous fluid, which allows the organs to glide smoothly against each other during movement and digestion. The peritoneum itself is a continuous membrane with these two layers, but the cavity refers specifically to the space between them. The other options describe the peritoneum itself or parts of organs rather than the cavity: the liver isn’t a space within the liver, and the stomach is lined by gastric mucosa, not a peritoneal membrane.