Surgical lobes of liver are divided on the basis of -a) Hepatic artery b) Hepatic vein c) Bile ducts d) Portal vein e) Central veins

## **Core Concept**
The liver is divided into surgical lobes based on its vascular and biliary supply. This classification is crucial for surgeons to understand the liver's anatomy for resections. The **Couinaud classification** (also known as the French system) is one of the commonly used systems, which divides the liver into eight segments based on the distribution of the hepatic veins and the portal vein.

## **Why the Correct Answer is Right**
The correct answer involves understanding that the surgical lobes of the liver are primarily divided based on the distribution of **hepatic veins** and the branching of the **portal vein**, **hepatic artery**, and **bile ducts**. However, among the given options, **hepatic veins** play a pivotal role in defining the surgical anatomy of the liver. The liver is divided into lobes based on the hepatic veins' drainage and the portal vein's supply.

## **Why Each Wrong Option is Incorrect**
- **Option A: Hepatic artery** - While the hepatic artery's branches are important for liver segmental anatomy, they are not the sole basis for dividing the liver into surgical lobes.
- **Option C: Bile ducts** - Similar to the hepatic artery, bile ducts are crucial for the segmental anatomy but are not the primary basis for surgical lobe division.
- **Option D: Portal vein** - The portal vein is essential for liver segmental anatomy. However, when considering surgical lobes specifically, the focus is more on hepatic veins.
- **Option E: Central veins** - Central veins are involved in the microcirculation of the liver and are not used to define surgical lobes.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that the **hepatic veins** are critical for defining the surgical anatomy of the liver. The Couinaud classification system divides the liver into eight segments based on the hepatic veins' distribution. Understanding this anatomy is vital for surgeons, especially during liver resections.

## **Correct Answer:** B.