In the most common anomaly of extrahepatic bile duct anatomy, the cystic duct
|B||inserts into the right hepatic duct|
|C||lies parallel to the common duct and enters it close to the' duodenum|
|D||passes anterior to the common duct and enters its left side|
a. Variations of the left hepatic duct are much less common than those of the right hepatic duct.
b. The cystic duct usually enters the common bile duct at an acute angle, but may run parallel to the common hepatic duct for a variable distance before joining it, or may join the right hepatic duct or a segmental right hepatic duct.
c. An accessory hepatic duct or cholecystohepatic duct (duct of Luschka) may also enter the gallbladder through the gallbladder fossa and, if encountered during a cholecystectomy, should be ligated to prevent a biliary fistula.
d. Anomalies of the gallbladder are much less frequent than variations in ductal anatomy.
e. Agenesis of the gallbladder has been reported (∼200 cases), and duplication of the gallbladder (two separate gallbladders, each with its own cystic duct) occurs in 1 of 4000 births.