EXTRAHEPATIC BILIARY SYSTEM

Caudate lobe drains only left hepatic duct 

Caudate lobe is usually drained by both left and right hepatic ducts.

• The functional anatomy of the liver is composed of 8 segments, each of which is supplied by its own portal triad or pedicle (composed of a portal vein, hepatic artery and a bile duct)
• These segments are further organised into 4 sectors separated by scissurae containing the 3 main hepatic veins. (Thus the three main hepatic veins divide liver into 4 sectors]. The 4 sectors are even further organized into right & left liver. Segments I to IV compose the left liver and segments V to VIII the right.
• Thus the right hepatic duct drains all segments of the right lobe and the left duct all segments of the left lobe. Caudate lobe or the segment I is drained by both right and left.

The right hepatic duct drains the bile ducts from segments V, VI, VII, and VIII, which constitute the right liver.

The right and left livers are drained by the right and left hepatic ducts, respectively, whereas the caudate lobe is drained by several small ducts joining the bifurcation and first several centimeters of both hepatic ducts.

Ref: Principles and Practice of Gastrointestinal Oncology edited by David Kelsen, 2008, Page 483.

Approximately 60% of the blood supply to the supraduodenal bile duct originates from the pancreaticoduodenal and retroduodenal arteries, whereas 38% of the blood supply originates from the right hepatic artery and cystic duct artery and 2 percent is non-axial.

Segment I, the caudate lobe, has its own biliary drainage. Variations of this are common, and in 78% of individuals the caudate lobe drains into both the left and right hepatic duct.

B i.e. Caudate lobe drains only left hepatic duct

D i.e. Usually opens into duodenum separate from main pancreatic duct

C i.e. Anteriorly related to first part of duodenum

B i.e. Anterior to first part of duodenum

–  The bile duct ends by piercing the medial wall of 2^nd part of duodenum, 8-10 cm distal to pylori usually after uniting with pancreatic duct to form hepatopancreatic ampulla or ampulla of Vater. Occasionally the pancreatic duct & bile duct open separately into the duodenum.

Bile duct (upper third or supraduodenal part) passes downwards in the free margin of lesser omentum (hepatoduodenal ligament), behind the liver, anterior to the portal vein and to the right of hepatic artery. Middle third (retro duodenal) part and lower third (infraduodenal – pancreatic) portion curves behind the first (1st) part of duodenum and head of pancreas respectively; whereas both parts run in front of (anterior to) IVC.

–   In nut shell, common bile duct lies posterior to liver, duodenum (1^st part) & pancreas head (all organs); anterior to portal vein & IVC (both veins); and to the right of hepatic artery & gastro duodenal artery (both arteries).

Ans is b i.e. Segment III 

• “The left hepatic duct drains segments II, III, and IV, and the right hepatic duct drains segments V, VI, VII, and VIII. Segment I, the caudate lobe, has its own biliary drainage. Variations of this are common, and in 78% of individuals the caudate lobe drains into both the left and right hepatic duct.”- Diseases of the Liver and Biliary System in Children By Deirdre A. Kelly, Dame Sheila (FRW) Sherlock 3/e p7
• The right and left hepatic ducts join to form the common hepatic duct which joins the cystic duct to form the common bile duct.

• Functional anatomy of liver

• The functional anatomy of the liver is composed of 8 segments, each of which is supplied by its own portal triad or pedicle (composed of a portal vein, hepatic artery and a bile duct)
• These segments are further organised into 4 sectors separated by scissurae containing the 3 main hepatic veins. (Thus the three main hepatic veins divide liver into 4 sectors]. The 4 sectors are even further organized into right & left liver. Segments Ito IV compose the left liver and segments V to VIII the right.
• Thus the right hepatic duct drains all segments of the right lobe and the left duct all segments of the left lobe. Caudate lobe or the segment I is drained by both right and left.
  

Ans. is ‘c’ i.e. Non-synthetic absorbable 

Ans. is ‘D’ i.e., Laparoscopic cholecystectomy operation 

• BDI may occur after gallbladder, pancreas and gastric surgery, with laparoscopic cholecystectomy responsible for 80%-85% of them.
• Patients usually complain of diffuse abdominal pain, nausea, fever, and impaired intestinal motility.
• The two most frequent features are bile leak and bile duct obstruction.
•  BDI during laparoscopic cholecystectomy is twice as frequent compared to injuries during an open procedure.

Ans. B: Distended and palpable gall bladder

Palpable gallbladder (Courvoisier sign) may indicate gall bladder malignancy.

Ans. is ‘d’ i.e., Simple columnar

Gall bladder and common bile ducts are lined by simple columnar epithelium.

Ans. is ‘a’ i.e., Primary sclerosing cholangitis

• PSC is a fibrosing cholangitis of bile ducts leading to inflammatory strictures and obliteration of both intrahepatic and extrahepatic ducts with dilatation of preserved segments. It’s a progressive disease eventually resulting in secondary biliary cirrhosis.

Ans. is ‘a’ i.e., Ampulla of vater

• The bile duct runs downwards and backwards, first in the free margin of the lesser omentum, supraduodenal part; then behind the first part of the duodenum the retroduodenal part; and lastly behind, or embedded in, the head of pancreas infraduodenal part.
• Near the middle of the left side of the second part of the duodenum it comes in contact with the pancreatic duct and accompanies it through the wall of the duodenum, the intraduodenal part.
• The course of the duct through the duodenal wall is very oblique.
• Within the wall the two ducts usually unite to form the hepatopancreatic ampulla, or ampulla of Vater.
• The distal constricted end of the ampulla opens at the summit of the major duodenal papilla 8 to 10 cm distal to the pylorus.