The root peritone/o denotes which membrane?

• A. Muscle layer
• B. Peritoneum
• C. Skin
• D. Lung

Answer: (B)

Understanding medical roots helps you decode terms. The combining form peritone/o refers to the peritoneum, the serous membrane that lines the abdominal cavity and covers most abdominal organs. This membrane has two layers—the parietal peritoneum lining the cavity wall and the visceral peritoneum surrounding the organs—and terms built from this root relate to that structure, such as peritoneitis or peritoneal dialysis. The other options point to different parts: muscle layer is described with a root like my/o, skin with dermat/o, and the lung with pneumon/o or pulmon/o. Since peritone/o specifically means the peritoneum, it is the correct root for this question.