This endoscopic picture shows the papilla of Vater during ERCP with a side-viewing endoscope in a patient with normal anatomy (A). In contrast, (B) shows the papilla in a reverse position (at approximately 6 o'clock) as seen with a forward-viewing endoscope in a patient with Roux-en-Y gastric bypass. The sphincterotome (arrow) can be seen after advancing it through the accessory channel of the endoscope.
