With regard to hepatic anatomy, the falciform ligament divides the_____ from the____
The falciform ligament divides the left lateral section from the left medial section. The plane between the gallbladder fossa and the inferior vena cava (IVC-referred to as Cantlie's line) divides the right and left lobes. The falciform ligament, along with the round, triangular, and coronary ligaments may be divided in a bloodless plane during liver resection figure below.
Hepatic ligaments suspending the l iver to the diaphragm and anterior abdominal wall.
In situ l iver hilar anatomy with hepatoduodenal and gastrohepatic ligaments. Foramen of Winslow is depicted.
Couinaud l iver segments (I through VIII) numbered in a clockwise manner. The left lobe includes segments II to IV, the right lobe includes segments V to VIII, and the caudate lobe is segment I. IVC = inferior vena cava .
The most common variant of normal hepatic artery anatomy is:
Understanding the anatomic variants of the hepatic arterial supply is important to avoid complications during liver surgery. The standard arterial anatomy is as follows: the common hepatic artery arises from the celiac trunk, and then divides into the gastroduodenal and proper hepatic artery. In a standard configuration, the proper hepatic artery gives rise to the right gastric artery, but this is variable. The proper hepatic artery then divides into the right and left hepatic artery (Fig. below). However, this standard arterial configuration only occurs in 76% of patients. The most common variants include replaced right hepatic artery from the SMA (10-15%), replaced left hepatic artery from the left gastric artery (3- 10%), replaced right and left hepatic arteries (1-2%), and the completely replaced common hepatic artery from the SMA (1-2%) figure below.
Arterial anatomy of the upper abdomen and liver, including the celiac trunk and hepatic artery branches. a . = artery; LHA = left hepatic artery; RHA = right hepatic rtery.
Common hepatic artery anatomic variants. SMA = superior mesenteric artery.
Which of the following correctly pairs the segments of the liver and their associated systemic venous drainage?
There are three hepatic veins (right, middle, and left) that serve as the outflow for the hepatic circulation and drain into the suprahepatic IVC. The right hepatic vein drains segments V to VIII; the middle hepatic vein drains segment IV, as well as segments V and VIII; and the left hepatic vein drains segments II and III (Fig. below). The caudate lobe (segment I) drains directly in to the IVC.
Confluence of the three hepatic veins (HVs) and the inferior vena cava (IVC). Note that the middle and left hepatic veins (HVs) drain into a common trunk before entering the IVC. a . = artery; v. = vein.
With respect to the enterohepatic circulation ofbile, where are the majority of bile salts reabsorbed?
Bile salts are sodium and potassium salts of bile acids derived from cholesterol by hepatocytes. After synthesis, the primary bile acids cholic and chenodeoxycholic acid are conjugated to either taurine or glycine and then secreted into the biliary system. Approximately 90 to 95% of these primary bile salts and acids are absorbed by active transport at the terminal ileum, while the remainder enter the colon and are converted to secondary bile acids (deoxycholic and lithocholic acids) and their associated salts by resident bacteria. Bile acids and salts reabsorbed in the terminal ileum are reabsorbed through the portal circulation, while those lost in the stool are replaced by hepatic synthesis.
Which of the following compounds is not synthesized predominantly by the liver?
The liver is the largest gland in the body, and responsible for synthesis of the majority of plasma proteins. The liver produces approximately 10 g of albumin per day, and albumin measurement can therefore be used as a surrogate for liver synthetic function. This must be interpreted with caution, as albumin levels can be influenced by a host of factors unrelated to hepatic function, and albumin's long half-life (15-20 days) makes it a poor marker for acute hepatic dysfunction. Most clotting factors are synthesized predominantly in the liver, except for factor VIII. Due to this fact the prothrombin time (PT) and international normalized ratio (INR) may also be used as markers of hepatic synthetic function. However, these too should be interpreted with caution as other conditions, including vitamin K deficiency and warfarin use, may prolong a patient's PT/INR.
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