The Sphincter of Oddi is a smooth muscle valve that controls the flow of digestive juices from the pancreatic and bile duct into the small intestine. Sphincter of Oddi dysfunction occurs when the sphincter does not relax properly, which can cause issues such as pain and abnormalities of the liver and pancreas. Sphincter of Oddi Manometry is a test used during ERCP to measure the pressure of the muscle valve.