Which procedure visualizes the sigmoid colon?

• A. Sigmoidoscopy
• B. Colonoscopy
• C. Endoscopy
• D. Enteroscopy

Answer: (A)

Understanding the location helps: the sigmoid colon is the lower part of the large intestine, near the rectum. A sigmoidoscopy uses a flexible instrument inserted through the anus to inspect the distal portion of the colon, specifically the sigmoid colon and rectum. This targeted reach makes it the procedure designed to visualize the sigmoid colon directly.

In contrast, a colonoscopy uses a longer instrument to examine the entire colon, not just the sigmoid; an endoscopy focuses on the upper GI tract (esophagus, stomach, and duodenum); and an enteroscopy looks deeper into the small intestine. So, for visualizing the sigmoid colon, sigmoidoscopy is the best fit.