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1. All of the following are correct except :(a) The caterpillar cystic arteries are multiple branches supplying the gallbladder from an aberrant right hepatic artery.(b) Accessory hepatic arteries should always be preserved as they often are the only blood supply to a part of the liver.(c) The most common variation of the hepatic arterial supply is a replaced right hepatic artery arising from the superior mesenteric artery (SMA). (d) The cystic artery may cross posterior to the common bile duct. (e) Ligation of the common hepatic artery results in fulminant hepatic necrosis.Comments The proper hepatic artery most commonly arises from the common hepatic artery (a branch of the celiac trunk) after the takeoff of the gastroduodenal artery. It then courses towards the liver and branches into the right and left hepatic arteries and subsequent segmental branches.Anatomical variations in this vascular tree are common as the biliary tree originates at the junction of foregut and midgut (i.e., middle of the second portion of the duodenum at the ampulla of Vater). While the primary artery of the foregut is the celiac artery, the SMA supplies the entire midgut with the two communicating at the origin of the biliary tree.The above-described classic anatomy is present in 75 % of cases. In 10 % of cases, the right hepatic artery arises from the SMA, in which case it courses towards the liver to the right of the bile duct coming behind the pancreas. This course puts the artery at risk both during biliary and pancreatic surgery [ 1 ] (Fig. 17.1 ).Also in 10 % of cases, the left hepatic artery arises from the left gastric artery, reaching the liver through the gastrohepatic ligament (lesser omentum). In 3 % of cases, both the right and left hepatic arteries have an anomalous origin. In 2 % of cases, the common hepatic artery originates from the SMA.Anomalous hepatic arteries may be accessory or replaced. Like the name implies, accessory arteries coexist with anatomically normal branches and may be sacrifi ced. On the other hand, replaced arteries are the only supply to a given area of liver parenchyma and should be preserved. In practice, all anomalous liver arteries must be considered replaced rather than accessory.The cystic artery is classically described as a branch of the right hepatic artery, reaching the gallbladder deep to the lymph node of Lund in Calot's triangle. However, as is the case with all biliary vascular anatomy, anatomical variations are present. One of such variations is the caterpillar cystic artery, reported in 4-16 % of cases. In this setting, a right hepatic with a premature division, or arising from the SMA courses anomalously close to the cystic duct, often giving multiple small branches to the cystic duct and gallbladder. This anatomy may predispose to injury to the right hepatic artery as it can be confused with the cystic artery [ 2 ] (Fig. 17.2 ).While the cystic artery normally reaches the gallbladder coursing anterior to the common bile duct, it may also be found posterior to it, case in which it ...