The part of the ventral duct connecting the dorsal and ventral fusion point to the major papilla is called the duct of Wirsung. The dorsal duct proximal to this fusion point is known as the Main Pancreatic Duct. The smaller continuation of the dorsal duct is called the duct of Santorini and drains into the minor papilla. With this configuration, the majority of drainage occurs through the major papilla through the duct of Wirsung. (2, 3)
A number of congenital ductal variations can occur as a result of abnormal ductal fusion during embryological development.
The most common variation is Pancreatic Divisum, in which the two pancreatic ductal systems do not fuse, leaving the majority of pancreatic drainage to occur through the duct of Santorini into the minor papilla. (3)
When the duct of Santorini forms a loop or sigmoid curve as it enters the minor papilla, an uncommon anomaly can be seen called 'Ansa Pancreatica'. At ERCP, the looping branch of Ansa Pancreatica may resemble the annular pancreas type of ductal variation. However, in Ansa Pancreatica, the looping branch courses toward the minor papilla, but it will not cross the duodenum, as is seen in annular pancreas. (2)
It has been proposed that the Ansa branch joins the main duct at an oblique angle, which may cause poor drainage of the pancreatic secretions, leaving the patient more prone to conditions such at pancreatitis. (1)
The association between the 'Ansa Pancreatica' variant and pancreatitis is speculative. Further studies are needed to establish the validity of this relationship.
For now, the recognition of this variant on imaging is incidental with no recommendation for follow-up or intervention. (1)
