Which root corresponds to the sigmoid colon?

• A. Rect/o
• B. Jejun/o
• C. Colon/o
• D. Sigmoid/o

Answer: (D)

In medical terminology, a combining form names a specific body part, and sigmoid/o designates the sigmoid (S-shaped) part of the large intestine. The sigmoid colon is that S-shaped section between the descending colon and the rectum, so the root that corresponds to it is sigmoid/o. The other roots refer to different parts—rect/o for the rectum, jejun/o for the jejunum, and colon/o for the colon itself—so they don’t match the sigmoid colon.