Three hundred normal upper gastrointestinal examinations as well as 50 studies demonstrating duodenal diverticula were analyzed to better characterize the aspects of normal duodenal anatomy pertinent to diagnosis of pancreatic disease. The results are applied to distorted duodenal diverticula, depression of the duodenojejunal junction, duodenal indentations resulting from gallbladder or common bile duct enlargement and enlargement of the duodenal papilla. Common misconceptions concerning these signs are clarified. In addition barium reflux into the common bile duct and localized duodenal spasm on hypotonic duodenography are discussed.