Where are the spiral valves of Heister located?

The spiral valves of Heister are small, helical folds found within the cystic duct. Their primary function is to help regulate the flow of bile into and out of the gallbladder, playing a crucial role in the storage and drainage of bile. These valves allow bile to remain in the gallbladder while preventing reflux back into the common bile duct. They also help to maintain the patency of the duct, particularly when the gallbladder contracts, ensuring efficient bile flow during the digestive process.

The presence of these valves in the cystic duct specifically highlights their importance in the anatomical and functional relationship between the gallbladder and the biliary tree, as they assist in accommodating changes in pressure and the movement of bile. This anatomical feature emphasizes the specialized adaptations found in the bile ducts of the hepatobiliary system.