A short Kocher incision does not cause any functional deficit of the rectus abdominis muscle. However, a very long Kocher incision may result in weakness of the rectus, especially if several segmental nerves are divided. The superior epigastric artery and vein lie posterior to the rectus abdominis muscle,
about halfway (at this level) between the linea alba and the costal margin. These vessels are generally small and are either divided with electrocautery or ligated and divided.

The falciform ligament (and its contained ligamentum teres hepatis, in the free edge of the falciform ligament) runs from the umbilicus to the fissure separating the right and left lobes. This lies to the right of the midline, so the falciform ligament is oriented with its left surface in contact with liver and its right in contact with the anterior parietal peritoneum. If the falciform and round ligaments must be divided, this should be done between clamps. The reasons for this are twofold. First, the round ligament, which is the obliterated left umbilical vein, may retain a patent lumen. Second, paralleling the round ligament are a variable number of paraumbilical veins, which provide a potential collateral circuit between the portal vein and the caval system via the superficial veins of the abdomen.

The right and left hepatic ducts leave their corresponding liver lobes and unite close to the porta hepatis to form the common hepatic duct, typically the most anterior tubular structure in this region. The cystic duct, which drains the gallbladder, joins the common hepatic duct at a variable distance from the porta hepatis and at a variable angle. This union forms the bile duct.

The gallbladder is a diverticulum of the extrahepatic biliary tree. From the cystic duct, the gallbladder is divided into a narrow neck (in which spirally arranged folds of mucosa form the so-called valve of Heister), a tapering body, and an expanded fundus that extends beyond the inferior border of the liver. Frequently, an asymmetric bulging of the right side of the neck may occur. This bulge, known as the infundibulum of the gallbladder (or Hartmann’s pouch), may be bound down toward the first part of the duodenum by a cholecystoduodenal ligament, the right edge of the lesser omentum. This ligament must be divided and the infundibulum (Hartmann’s pouch) mobilized to clearly identify the cystic duct.

The boundaries of the cystohepatic (Calot’s) triangle are the cystic duct inferiorly, the common hepatic duct medially, and the right lobe of the liver superiorly. It contains the right hepatic duct and right hepatic artery (usually posterior to the duct) in the superior part of the triangle, and the cystic artery more inferiorly. Anomalous vessels and bile ducts are common. The right hepatic artery can lie anterior to the right hepatic duct, or it may be up to 1 cm distant from the duct. Because its course briefly parallels the cystic artery, it can be mistaken for the latter vessel. The cystic artery, typically a branch of the right hepatic artery, can arise from any artery in the vicinity (e.g., the left hepatic, common hepatic, gastroduodenal, superior mesenteric, etc.). However, regardless of its origin, it usually passes through the cystohepatic (Calot’s) triangle.

Skeletonization of the cystic duct from the neck of the gallbladder to the bile duct is necessary, because it allows the surgeon to verify its identity. Variations in the biliary apparatus are also common. There can be accessory hepatic ducts (usually from the right), which can be mistaken for the cystic duct; bifurcated cystic ducts; multiple cystic ducts; and even absence of a cystic duct.