Wednesday, 13 April 2011
Common bile duct (ductus choledochus)
Formed by the union of the common hepatic duct and the cystic duct (from the gall bladder). It is later joined by the pancreatic duct to form the ampulla of Vater. There, the two ducts are surrounded by the muscular sphincter of Oddi.
Dilated in case of outflow obstruction.
The consensus is that most people have a common bile duct diameter of around 5mm, +/- 1 mm. However, there are reports were people with no hepatobilliary disease have a "normal" common bile duct size up to 10 mm. Also, there is a correlation between common bile duct diameter and age. Most physicians would like to check things further if the common bile duct diameter is greater than about 7 mm, particularly if there are symptoms indicating hepatobilliary disease (abdominal pain with or without jaundice, fever etc.). Finally, even "normal" common bile duct sizes do not exclude the possibility of disease (such as stones).
CBD is considered dilated in adults if its diameter > 7mm.