The Gallbladder and Biliary Ducts

The liver | Main Anatomy Index | The pancreas

Last updated 30 March 2006

The Gallbladder

• This is a piriform (pear-shaped) sac that lies along the right edge of the quadrate lobe of the liver.
• It sits in a shallow depression on its visceral surface, called the gallbladder fossa.

• It hangs inferiorly like a pear with the cystic duct representing its stalk.
• Its rounded fundus usually projects below the inferior border of the liver.

• It is normally covered on its posterior and inferior surfaces by peritoneum.
• Occasionally, it may be completely invested in peritoneum and may even be connected to the liver a short mesentery.

• The gallbladder stores and concentrates bile secreted by the liver.
• It can usually store between 30-60 mL of bile.

• For the purposes of description it is divided into a fundus, body and neck.

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The Fundus of the Gallbladder

• It is its wide end that projects from the inferior border of the liver.

• It is usually located at the tip of the 9^th costal cartilage in the midclavicular line.
• This is where the linea semilunaris marks the lateral edge of the rectus abdominis and meets the costal margin.

• It is directed anteriorly, and to the right where it comes into relationship with the posterior surface of the anterior abdominal wall and the descending part of the duodenum.

The Body of the Gallbladder

• Its main part is directed superiorly, posteriorly, and to the left from the fundus.
• It lies in contact with the visceral surface of the liver, to which it is attached by loose connective tissue.

• It also contacts the right part of the transverse colon and the superior part of the duodenum.

The Neck of the Gallbladder

• It is narrow, tapered, and directed toward the porta hepatis.
• It makes an S-shaped bend and is somewhat constricted as it becomes continuous with the cystic duct.

• The neck is twisted in such a way that its mucosa is thrown into a spiral fold (valve of Heister).
• The neck serves as a guide to the omental (epiploic) foramen, which lies to its immediate left, posterior to the free margin of the lesser omentum.

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The Cystic Duct

• The duct of the gallbladder is 2-4 cm long.
• At first it runs superiorly and to the left from the gallbladder.
• It then turns posteriorly and finally inferiorly to join the common hepatic duct to form the bile duct.

• The cystic duct runs between the layers of the lesser omentum, usually parallel to the hepatic duct, before joining it near the porta hepatis.

• The mucous membrane of the cystic duct is thrown into a spiral fold with a core of smooth muscle.
• This fold is continuous with the spiral fold of the neck of the gallbladder.
• As it coils along the cystic duct, it has the appearance of a spiral valve.

• The spiral fold keeps the cystic duct constantly open so that:

1. Bile can easily pass into the gallbladder when the bile duct is closed by the choledochal sphincter and/or the hepatopancreatic sphincter.
2. Bile can pass the opposite direction, into the duodenum, when the gallbladder contracts. A hormonal mechanism (cholecystokinin) is involved in gallbladder contraction.

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Arterial Supply of the Gallbladder and Cystic Duct

• The gallbladder is supplied by the cystic artery, which commonly arises from the right hepatic artery, in the angle between the common hepatic artery and the cystic duct.

Venous Drainage of the Gallbladder and Cystic Duct

• Cystic veins join the right branch of the portal vein.
• The veins of the fundus and body of the gallbladder pass directly into the liver.

Lymphatic Drainage of the Gallbladder and Cystic Duct

• Most lymph passes to the hepatic lymph nodes, often via the cystic lymph node, near the neck of the gallbladder.
• Efferent vessels from these lymph nodes pass to the coeliac lymph nodes.

Innervation of the Gallbladder and Cystic Duct

• The nerves pass along the cystic artery from the coeliac plexus (sympathetic), the vagus nerve (parasympathetic) and the right phrenic nerve (sensory).
• The hepatic plexus also issues an offshoot to the cystic artery.

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The Biliary Ducts

• Bile is secreted by the hepatocytes into bile canaliculi, the smallest branches of the intrahepatic duct system.
• Most of the canaliculi drain into small interlobular bile ducts, which joint with others to form progressively larger ducts.

• Eventually, right and left hepatic ducts are formed that emerge from the porta hepatis.
• The right hepatic duct drains the right lobe of the liver and the left, the left lobe.

• Shortly after leaving the porta hepatis, the right and left portal ducts unite to form the common hepatic duct.

• About 4 cm in length, it passes inferiorly and to the right, between the layers of the lesser omentum.

The Bile Duct

• The common hepatic duct is joined on the right side at an acute angle by the cystic duct from the gallbladder to form the bile duct (common bile duct).
• This large duct is 8 to 10 cm long and 5 to 6 mm in diameter.

• It runs in the free edge of the lesser omentum with the hepatic artery and portal vein.
• It passes inferiorly, anterior to the omental foramen, where it is anterior to the right edge of the portal vein and on the right side of the hepatic artery.

• As it passes posterior to the pancreas, occupying a groove in the posterior part of the head or embedded in it.

• As it runs posterior to the duodenum, the bile duct lies to the right of the gastroduodenal artery.

• On the left side of the descending part of the duodenum, the bile duct comes into contact with main pancreatic duct.
• The two of them usually run obliquely through the wall of the duodenum, where they usually unite to form the hepatopancreatic ampulla.
• The distal constricted part of the ampulla opens into the descending part of the duodenum, at the summit of the major duodenal papilla, 8 to 10 cm from the pylorus.

• The circular muscle around the distal end of the bile duct is thickened to form the choledochal sphincter (G. choledochus, containing bile).
• This is a muscular sheath that surrounds the bile duct just before it penetrates the duodenal wall.

• There is also a sphincter around the hepatopancreatic ampulla, the hepatopancreatic sphincter.
• This sphincter controls both the discharges of bile and pancreatic juice into the duodenum.

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Arterial Supply of the Bile Duct

• The bile duct is supplied by several arteries:

1. The distal or retroduodenal part is supplied by the posterior superior pancreaticoduodenal artery;
2. The middle part is supplied by the right hepatic artery;
3. The proximal part is supplied by the cystic artery.

• The supraduodenal branches of the gastroduodenal artery also supply the bile duct as it passes posterior to the superior part of the duodenum.

Venous Drainage of the Bile Duct

• The veins from the proximal part of the bile duct and the hepatic ducts generally enter the liver directly.
• The posterior superior pancreaticoduodenal vein drains the distal part of the bile duct, and empties into the portal vein or one of its tributaries.

Lymphatic Drainage of the Bile Duct

• Lymph passes to the cystic lymph node near the neck of the gallbladder, the nodes of the omental foramen, and the hepatic lymph nodes.
• Efferent lymph vessels pass to the coeliac nodes.

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