[Morphologic studies of the extrahepatic bile ducts in infancy, childhood and youth].

Morphology of the extrahepatic bile ducts was examined with light microscopic methods in 55 human cases from the age of 28 gestational weeks up to 19 years. We found that barrel-shaped cells, rod-shaped cells and goblet cells are obligatory components of the bile duct epithelium in infancy. Tunica fibromuscularis of extrahepatic bile ducts consists of connective tissue. Increase of collagen fibers and fibers stained by resorcin fuchsin was observed during development. Neither in hepatic bile duct nor in common bile duct a muscle layer exists. A third of all bile ducts was free of muscles. Sparse muscle bundles in the other cases seem not able to generate bile duct motility. A morphological correlate to the sphincter of Mirizzi and Bernhard we did not find. Tunica adventitia and surrounding connective tissue contain many spacious lymphatic vessels.