The liver is tethered by the following ligaments:

• The falciform ligament attaches the liver anteriorly to the diaphragm and the anterior abdominal wall above the umbilicus.

• The coronary ligaments extend laterally to attach the liver to the diaphragm. Beginning at the suprahepatic inferior vena cava (IVC), the lateral extensions of the coronary ligaments form the triangular ligaments (right and left), which are also attached to the diaphragm.

The anatomical division of the liver into the eight classic Couinaud segments has no practical application in traumatic liver resection, where the resection planes are nonanatomical and are dictated by the extent of injury. However, the external anatomical landmarks may be useful in planning operative maneuvers.

• The plane between the center of the gallbladder and IVC runs along the middle hepatic vein, and serves as the line of division between the right and left lobes.

• The left lobe is divided by the falciform ligament into the medial and lateral segments.

• Dissection along the falciform ligament should be performed carefully, so as to avoid injury to the portal venous supply to the medial segment of the left lobe inferiorly and the hepatic veins superiorly.

The retrohepatic IVC is approximately 8–10 cm long and is partially embedded into the liver parenchyma. In some cases, the IVC is completely encircled by the liver, further complicating exposure and repair.

There are three major hepatic veins (right, middle, and left), as well as multiple accessory veins. The first 1–2 cm of the major hepatic veins are extra-hepatic, with the remaining 8–10 cm intra-hepatic. In approximately 70% of patients, the middle hepatic vein joins the left hepatic vein before entering the IVC.

The common hepatic artery originates from the celiac artery. It is responsible for approximately 30% of the hepatic blood flow, but supplies 50% of the hepatic oxygenation. It branches into the left and right hepatic arteries at the liver hilum in the majority of patients. In a common anatomical variant, the right hepatic artery may arise from the superior mesenteric artery. Less frequently, the entire arterial supply may arise from the superior mesenteric artery. Alternatively, the left hepatic artery may arise from the left gastric artery in 15–20% of patients.

The portal vein provides approximately 70% of hepatic blood flow, and 50% of the hepatic oxygenation. It is formed by the confluence of the superior mesenteric vein and the splenic vein behind the head of the pancreas. The portal vein divides into right and left extrahepatic branches at the level of the liver parenchyma.

The porta hepatis contains the hepatic artery (medial), common bile duct (lateral), and portal vein (posterior, between the common bile duct and the hepatic artery).

The right hepatic duct is easier to expose after removal of the gallbladder.

The left hepatic duct, the left hepatic artery, and the left portal vein branch enter the undersurface of the liver near the falciform ligament.

The pericardium envelops the heart and attaches to the roots of the great vessels. This includes the ascending aorta, pulmonary artery, pulmonary veins, the last 2–4 cm of superior vena cava, and inferior vena cava.

The phrenic nerves descend on the lateral surfaces of the pericardium.

Acute accumulation of as little as 200 mL of fluid in the pericardial sac may result in fatal cardiac tamponade.

The right atrium is paper thin, approximately 2 mm. The left atrium is slightly thicker at approximately 3 mm.

The right ventricle is approximately 4 mm thick and the left ventricular wall thickness is approximately 12 mm.

The two main coronary arteries, left main and right coronary arteries, originate at the root of the aorta, as it exits the left ventricle. The left main coronary artery divides into the left anterior descending artery (LAD) and the circumflex artery, and provides blood supply to the left heart. The right coronary artery divides into the right posterior descending and acute marginal arteries, supplying blood to the right heart, as well as the sinoatrial and atrioventricular nodes responsible for regulating cardiac rhythm.

The anterior abdominal wall has four muscles: The external oblique, the internal oblique, the transversalis, and the rectus muscles. The aponeuroses of the first three muscles form the rectus sheath, which encloses the rectus abdominis muscle.

The linea alba is a midline aponeurosis that runs from the xiphoid process to the pubic symphysis and separates the left and right rectus abdominis muscles. It is widest just above the umbilicus, facilitating entry into the peritoneal cavity.

For vascular trauma purposes, the retroperitoneum is conventionally divided into four anatomic areas:

• Zone 1: Extends from the aortic hiatus to the sacral promontory. This zone is subdivided into the supramesocolic and inframesocolic areas. The supramesocolic area contains the suprarenal aorta and its major branches (celiac axis, superior mesenteric artery (SMA), and renal arteries), the upper inferior vena cava (IVC) with its major branches, and the superior mesenteric vein (SMV). The inframesocolic area contains the infrarenal aorta and IVC.

• Zone 2: Includes the kidneys, paracolic gutters, renal vessels, and ureters.

• Zone 3: Includes the pelvic retroperitoneum, containing the iliac vessels and ureters.

• Zone 4: Includes the perihepatic area, with the hepatic artery, the portal vein, the retrohepatic IVC, and hepatic veins.