Variants of pancreatic duct system of importance in endoscopic retrograde cholangiopancreatography. Observations on autopsy specimens.

A postmortem radiographic investigation of 330 pancreas specimens showed a total frequency of 10 per cent for the 3 variants of the pancreatic duct system, in which the main pancreatic duct drained to the minor duodenal papilla (type III). In no instance did the main duct drain into the duodenum distal to the major papilla, onto which the common bile duct drained as usual. In the most common variant, type III-B, a separate accessory duct drained part of the pancreatic head onto the major papilla. In the remaining cases either an analogous accessory duct existed, communicating with the main duct (type III-A) or no accessory duct at all (type III-C). The different features of the accessory and main duct systems of type III in the pancreatic head varied widely. In types III-A and III-B, the corresponding ventral and dorsal pancreatic primordia formed more or less of mainly the posterior and anterior parts of the pancreatic head, respectively.