Bow and arrow sign

Content sourced from Wikipedia, licensed under CC BY-SA 3.0.

The bow and arrow sign is a quick clue used during colonoscopy to locate the ileocecal valve, which marks the end of the colon and shows that the entire colon has been examined. In the cecum you can see two landmarks: the appendiceal orifice (a curved indent where the appendix is) and the ileocecal valve (a puckered fold). The sign uses the curve of the appendiceal orifice to point toward the valve, like a bow guiding an arrow, and following that direction lets the doctor enter the terminal ileum. This sign, along with identifying the anus, helps confirm the whole colon has been visualized.