Ashley Davidoff MD
Emryological Basis – The Duct of Santorini
The accessory duct of Santorini (APD) is a remnant of the former main pancreatic duct that was a continuum of the duct in the neck body and tail with the dorsal portion of the duct. With the rotation of the ventral portion from the lateral aspoect of the duodenum to the medial side, the duct of the body and tail lose their connection with the dorsal portion of the head and form a bond with the ventral duct, isolating the dorsal duct. he result of how the dorsal duct ends up is very variable and except for pancreas divisum usually has no significant consequence. he duct may be blind, keep some connection with the main duct, retain a full embryologic connection with the duct of the body divisum or drain independantly into the duodenum.
The ERCP demonstrates a smaller accessory duct of Santorini which is filling from the MPD (duct of Wirsung) injection. The accessoryduct enters the duodenum more superiorly. 04184 Courtesy Ashley Davidoff MD
These images from an ERCP shows the CBD, (green) MPD (light pink) and the accessory pancreatic duct (rose). In this instance the MPD and the accessory duct are connected and they both have egress into the duodenum. The secondary ducts in the head are filled, but are not seen in the body or tail. Note also the low lying insertion of the cystic duct(dark green) which is an important anomaly to note for the surgeon.39963c01
Courtesy Ashley Davidoff MD
The duct of Santorini represents the remnant of the dorsal ductal supply to the head and it persists in a variety of patterns. Its persistent connection to the duodenum via the minor papilla is seen in 50-70% of patients. When it is not connected to the duodenum it serves as an accessory branch connected to the main ductal system.The accessory pancreatic duct of Santorini, usually communicates with the main duct and passes transversely to the right in the upper part of the head of the pancreas. The duct of Santorini lies anterior to the intrapancreatic common bile duct and usually opens into the proximal portion of the second part of the duodenum at the minor papilla, proximal to the ampulla of Vater. In 2-6% of healthy people pancreas divisum exists. In this anomaly the dorsal duct of the body retains it embryonic union with the dorsal duct in the head and opens separately into the minor duct papilla 1-2 cms upstream of the main papilla. The ventral duct remains rudimentary and opens seprate to or with the CBD.
This is the injection of the MPD of the case above showing a small ventral duct of Wirsung. The case represents pancreas divisum as seen by ERCP. The main duct was found opening separately within the pailla near the opening of the CBD. 40617 Courtesy Ashley Davidoff MD
This is the injection of the MPD of the case above showing a small ventral duct of Wirsung. The case represents pancreas divisum as seen by ERCP. The main duct was found opening separately within the pailla near the opening of the CBD. 40617 Courtesy Ashley Davidoff MD
This combination study of pancreas divisum consists of a CTscan with the MPD by passing the CBD (a) magnified in b, with a slightly dilated appearance in the body of the pancreas in c. The US equivalence of this finding is noted in d, while e shows the MPD and ventral duct exiting cranial to the entrance of the CBD. The last injection of the ERCP is the injection of the MPD showing a small ventral duct of Wirsung. The findings are pathognomonic of pancreas divisum. Courtesy Ashley Davidoff MD 40617 c01