Right and left hepatic ducts join as the common hepatic duct, which the cystic duct joins to form the common bile duct
Mnemonic
Trace it downwards, and every junction has a name:
- Right and left hepatic ducts join to form the common hepatic duct
- The cystic duct joins it to form the common bile duct
- The common bile duct runs in the free edge of the lesser omentum, then behind the first part of the duodenum, then through the head of the pancreas
- It joins the main pancreatic duct to form the ampulla of Vater, opening at the major duodenal papilla in the second part of the duodenum, guarded by the sphincter of Oddi
“Duct to the right, artery to the left, vein behind” for the portal triad in the free edge of the lesser omentum.
The cystic duct has spiral valves of Heister, which is why stones impact there and why cannulation can be difficult.
Calot’s triangle, bounded by the cystic duct, common hepatic duct and the liver edge, contains the cystic artery and is the region that must be cleared to achieve the critical view of safety before clipping anything.
Expansion
- Right and left hepatic ducts leave the liver at the porta hepatis
- They unite as the common hepatic duct
- The cystic duct joins it to form the common bile duct
- The common bile duct descends behind the first part of the duodenum, then through the head of the pancreas
- It joins the pancreatic duct at the ampulla of Vater
The duct is about 8 cm long and normally under 6 mm in diameter (allowing about 1 mm per decade over 60, and wider after cholecystectomy).
Its retropancreatic course is why carcinoma of the pancreatic head causes painless obstructive jaundice, and its position in the free edge of the lesser omentum places it in the portal triad, duct to the right, artery to the left, vein behind.
The spiral valves of Heister in the cystic duct keep it patent but can make cannulation difficult.