Which of the following anatomic features of the biliary system are important considerations in operative cholangiography?

A. The left hepatic duct comes off farther anterior than the right one.

B. At the confluence there may be more than just a right and a left hepatic duct.

C. Dissection of the triangle of Calot is more important than cholangiography in preventing bile duct injury.

D. Segments V, VII, or VIII sometimes join the biliary system below the confluence. 

DISCUSSION: All of these features are important. The angle of takeoff of the left hepatic duct may make operative visualization difficult with the patient in the supine position. Because there may be more than two major hepatic ducts, visualization of two large ducts does not ensure that the system is normal. Ducts from any of the right-side segments can join below the confluence. Dissecting one superior edge of the gallbladder before it joins the cystic duct is particularly important in preventing injury.