Common bile duct
Diagram of the biliary tree showing the common bile duct
Part ofBiliary tract
Latinductus choledochus,[1]
ductus biliaris[1]
Anatomical terminology
1. Bile ducts: 2. Intrahepatic bile ducts, 3. Left and right hepatic ducts, 4. Common hepatic duct, 5. Cystic duct, 6. Common bile duct, 7. Ampulla of Vater, 8. Major duodenal papilla
9. Gallbladder.
10–11. Right and left lobes of liver.
12. Spleen.
13. Esophagus.
14. Stomach.
15. Pancreas: 16. Accessory pancreatic duct, 17. Pancreatic duct.
18. Small intestine: 19. Duodenum, 20. Jejunum
21–22. Right and left kidneys.
The front border of the liver has been lifted up (brown arrow).[3]

The bile duct[1][4] (formerly known as the common bile duct[4]) is a part of the biliary tract.[4] It is formed by the union of the common hepatic duct and cystic duct. It ends by uniting with the pancreatic duct to form the hepatopancreatic ampulla. It possesses its own sphincter to enable regulation of bile flow.


The bile duct is some 6–8 cm long, and normally up to 8 mm in diameter.[4]

Its proximal supraduodenal part is situated within the free edge of the lesser omentum. Its middle retroduodenal part is oriented inferiorly and right-ward, and is situated posterior to the first part of the duodenum, and anterior to the inferior vena cava. Its distal paraduodenal part is oriented still more right-ward, is accommodated by a groove upon (sometimes a channel within) the posterior aspect of the head of the pancreas, and is situated anterior to the right renal vein.[4]

The bile duct terminates by uniting with the pancreatic duct (at an angle of about 60°) to form the hepatopancreatic ampulla.[4]

The distal extremity of the bile duct invariably features its own sphincteric muscle (the pancreatic duct and the hepatopancreatic ampulla usually possess sphincters of their own to allow the flow of pancreatic juice to be regulated independently, however, these two can be absent).[4]

Clinical significance

Several problems can arise within the common bile duct, usually related to its obstruction. Opinions vary slightly on the maximum calibre of a normal CBD, but 6mm is one accepted upper limit of normal [5] with a further 1mm diameter allowed for each decade over 60 years.

It normally gets slightly dilated after cholecystectomy, with upper limit (95% prediction interval) being about 10 mm after a few months.[6]

On abdominal ultrasonography, the common bile duct is most readily seen in the porta hepatis (where the CBD lies anterior to the portal vein and hepatic artery). The absence of Doppler signal distinguishes it from the portal vein and hepatic artery.


Tumours in the head of the pancreas may come to obstruct the distal bile duct.[4]

If obstructed by a gallstone, a condition called choledocholithiasis can result.[7] In this obstructed state, the duct is especially vulnerable to an infection called ascending cholangitis. One form of treatment is a cholecystenterostomy. Rare deformities of the common bile duct are cystic dilations (4 cm), choledochoceles (cystic dilation of the ampula of Vater (3–8 cm)), and biliary atresia.


Obstruction of the common bile duct and related jaundice has been documented since at least since the time of Erasistratus.[8]

Additional images

See also


  1. ^ a b c "Anatonomina". Retrieved 2023-07-07.
  2. ^ Agabegi, Steven S.; Agabegi, Elizabeth D. (23 August 2012). Step-Up to Medicine. Lippincott Williams & Wilkins. p. 136. ISBN 9781609133603.
  3. ^ Standring S, Borley NR, eds. (2008). Gray's anatomy : the anatomical basis of clinical practice. Brown JL, Moore LA (40th ed.). London: Churchill Livingstone. pp. 1163, 1177, 1185–6. ISBN 978-0-8089-2371-8.
  4. ^ a b c d e f g h Sinnatamby, Chummy S. (2011). Last's Anatomy (12th ed.). pp. 263–266. ISBN 978-0-7295-3752-0.
  5. ^ Oh, Lawrence. "Common bile duct | Radiology Reference Article |". Radiopaedia. Retrieved 2021-08-30.
  6. ^ Feng, B; Song, Q (1995). "Does the common bile duct dilate after cholecystectomy? Sonographic evaluation in 234 patients". American Journal of Roentgenology. 165 (4): 859–861. doi:10.2214/ajr.165.4.7676981. ISSN 0361-803X. PMID 7676981.
  7. ^ Humes, H. David (2001). Kelley's Essentials of Internal Medicine. Lippincott Williams & Wilkins. p. 229. ISBN 978-0781719377.
  8. ^ Bateson, Malcolm C., ed. (1986). Gallstone Disease and its Management. Dordrecht: Springer Netherlands. p. Epidemiology (chapter). ISBN 9400941730.