A 50-year-old man comes in for a physical so he can attend a boy scout camp with one of his sons. You suggest a colonoscopy after he returns from camp. He agrees, but wants you to describe the procedure and potential risks and complications. You explain that the goal of a colonoscopy is to look at the entire length of the large intestine from the anus to the small intestine (ileocecal junction), observing polyps or diverticuli with a flexible fiber optic colonoscope inserted through the anus. There is a small risk of perforating the bowel especially when the colon takes a sudden turn or twists on itself at regions where it is intraperitoneal rather than attached to the posterior abdominal wall (retroperitoneal). Which of the following regions of the colon generally poses the greatest risk for perforation because the bowel takes either a sudden change in direction or is suspended by a mesentery?
A. Rectum, sigmoid colon and descending colon B. Sigmoid colon, descending colon and splenic flexure C. Sigmoid colon, splenic flexure and descending colon D. Sigmoid colon, splenic flexure and hepatic flexure E. Descending colon, transverse colon and ascending colon
Sigmoid colon, splenic flexure and hepatic flexure-(moore and dalley, pp 277 280.) the colon normally has two regions where it is retroperitoneal: the ascending and descending colon. there are also two normal points of flexure: the hepatic (right) and splenic (left) flexures. therefore, the sigmoid colon, splenic flexure, and hepatic flexure are the regions where the gastroenterologist has the greatest difficulty passing the fiberoptic scope, and thus have the greatest risk of bowel perforation. this is perhaps most easily visualized by looking at fig. 2.44 on p 278 of moore & dalley. other answers (answers a, b, c, and e) are not correct.