The bile ducts of the liver join with other ducts to form two main trunks, which leave the liver at the transverse fissure, and by their union form the hepatic duct.
The two main trunks of nearly equal size issue from the liver at the porta, one from the right (the right hepatic duct, formed by the union of the anterior branch and posterior branch), the other from the left lobe (the left hepatic duct formed by the union of a lateral branch and a medial branch).
These unite to form the hepatic duct, which passes downward and to the right for about 4 cm., between the layers of the lesser omentum, where it is joined at an acute angle by the cystic duct, and so forms the common bile duct. The hepatic duct is accompanied by the hepatic artery and portal vein.
The bile ducts of the caudate lobe directly comes to the two main trunks: the right duct of caudate lobe connects to the right hepatic duct and the left duct of the caudate lobe connect to the left hepatic duct.