Formation of the Common Hepatic Duct
The duct is part of the extrahepatic biliary tract. The right and left hepatic ducts (ductus hepatici dexter et sinister) merge to form the common hepatic duct (ductus hepaticus communis).
The right and left hepatic ducts and their segmental branches can exhibit anatomical variations; if either main duct is absent, the corresponding segmental ducts drain directly into the common hepatic duct.
Topographic Anatomy and Relations
The common hepatic duct emerges from the liver at the porta hepatis, which is situated among the fissures for the ligamentum teres, ligamentum venosum, and inferior vena cava.
Upon leaving the porta hepatis, the duct runs within the hepatoduodenal ligament (lig. hepatoduodenale). The structures contained within the porta hepatis and hepatoduodenal ligament include:
- proper hepatic artery (a. hepatica propria) and its right and left branches;
- portal vein (v. portae);
- autonomic nerves and lymphatic vessels.
Wall Structure and Dimensions
The average dimensions of the common hepatic duct are 4–5 cm in length and 4–5 mm in diameter.
Structural features:
- The mucosa is smooth and lacks folds.
- Mucous glands (glandulae mucosae ductulorum biliarium) are located within the submucosa of the extrahepatic bile duct walls.
Union with the Cystic Duct
About 2.5–3.0 cm below the confluence of the lobar ducts, the cystic duct (ductus cysticus) drains into the common hepatic duct. The cystic duct is approximately 3 cm long and 3–4 mm in diameter, arising from the gallbladder neck, forming two curves, and running superiorly and to the right.
Variants of cystic duct insertion into the common hepatic duct:
- Acute or obtuse angle;
- Parallel course alongside the common hepatic duct for a certain distance;
- Spiral course around the hepatic duct.
The union of these two ducts forms the common bile duct (ductus choledochus), which serves as the direct continuation of the common hepatic duct. It also lies within the hepatoduodenal ligament, measures 5–8 cm (sometimes up to 12 cm) in length, and possesses a muscular coat containing the sphincter of the common bile duct. The common bile duct opens at the apex of the major duodenal papilla.
Clinical Significance
In cases of intrahepatic cholangiocarcinoma or proximal extrahepatic bile duct cancer, if the anticipated future liver remnant (FLR) volume is less than 40%, selective portal vein embolization (PVE) of the ipsilateral branches (typically the right branch, and occasionally segment IV branches) is performed.
Changes in liver volume are assessed no earlier than 3–5 weeks post-embolization. PVE aims to induce compensatory hypertrophy of the future liver remnant and reduce the risk of post-hepatectomy liver failure. Surgical resection is performed once the remnant liver volume reaches ≥ 40%.