# Liver Anatomy > Liver anatomy for MBBS Anatomy: Couinaud segments, peritoneal ligaments and bare area, portal triad, Calot's triangle, dual blood supply and Pringle manoeuvre. - Canonical URL: https://prepelephant.com/topics/mbbs/anatomy/liver-anatomy - Exam / course: MBBS · Subject: Anatomy - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-02 - Last updated: 2026-10-02 - How to cite: "Liver Anatomy", PrepElephant, https://prepelephant.com/topics/mbbs/anatomy/liver-anatomy ## Direct answer Eight functionally independent segments, each with its own portal triad branch and hepatic vein tributary, organise the 1.2–1.5 kilogram liver — the largest gland in the body — filling the right hypochondrium and epigastrium. It receives roughly 1.5 litres of blood per minute, about 75 per cent from the portal vein and 25 per cent from the hepatic artery proper, both entering at the porta hepatis with the right and left hepatic ducts. The falciform ligament divides it anatomically into right and left lobes, but the functional division follows Cantlie's line from the gallbladder bed to the inferior vena cava (the plane of the middle hepatic vein): left Couinaud segments 2, 3 and 4 (plus caudate segment 1), right segments 5, 6, 7 and 8. The bare area, where it touches the diaphragm between the layers of the coronary ligament, is its only non-peritoneal surface. ## What you must remember - **Peritoneal derivatives:** ligamentum teres (obliterated left umbilical vein) in the falciform ligament free edge; ligamentum venosum (fibrosed ductus venosus) in the fissure between caudate and left lobe; both are fetal shunts worth one viva question each. - **Porta hepatis contents:** portal vein posteriorly, hepatic artery proper anteromedially, right and left hepatic ducts anterolaterally, plus lymphatics and the hepatic nerve plexus — bile duct, artery, vein, in that order ("DAV" from front). - **Segmental anatomy:** caudate lobe is segment 1 (drains directly into the IVC — it hypertrophies in Budd-Chiari syndrome); quadrate lobe belongs functionally to the left as segment 4; a right hepatectomy removes segments 5–8, a left lateral section segments 2 and 3 (the paediatric transplant graft). - **Gallbladder:** 7–10 centimetres, 50-millilitre capacity; fundus, body, neck with Hartmann's pouch; supplied by the cystic artery from the right hepatic artery within the hepatocystic (Calot's) triangle. - **Calot's triangle:** cystic duct below-laterally, common hepatic duct medially, liver surface above — the dissection zone where the cystic artery, and occasionally an aberrant right hepatic artery or Moynihan's hump, lives. - **Vascular facts for exams:** the hepatic artery is an end artery; hepatic veins drain into the IVC just below the diaphragm, torn in retrohepatic injuries with high mortality. - **Surface projection:** the lower border follows the right costal margin; the upper border reaches the fifth rib in the midclavicular line — the span percussed in every clinical examination. ## Anatomy of a cholecystectomy Laparoscopic cholecystectomy is segmental anatomy in motion. The grasper lifts the gallbladder fundus cephalad, opening Calot's triangle; dissection clears fat and fibrous tissue until the "critical view of safety" is achieved — the cystic duct and cystic artery seen entering the gallbladder with a window of liver base behind them, and the lower third of the gallbladder freed from the liver bed. Only then are clips applied, because the catastrophes of this operation are anatomical: a right hepatic artery mistaken for the cystic (bleeding, hepatic ischaemia), or a common bile duct mistaken for the cystic (duct injury, the most feared litigation in Indian surgical practice). A stone in Hartmann's pouch can compress the common hepatic duct (Mirizzi syndrome), and a short cystic duct is a variant that traps the unwary. For trauma, the same geography reappears: the Pringle manoeuvre compresses the portal triad in the free edge of the lesser omentum, controlling hepatic arterial and portal bleeding; retrohepatic caval bleeding continues despite it. ## How the exam frames it The standard viva opener is "anatomical versus physiological lobes" — the answer must include Cantlie's line, the middle hepatic vein, caudate as segment 1 and quadrate as segment 4, because that quartet is the whole distinction. The second favourite is why Couinaud numbering matters: each segment is a resectable unit with autonomous inflow and outflow, which is how living-donor and split-liver transplantation became possible. Third, the bare area: the IVC and hepatic veins traverse this naked strip, an embryological consequence of the septum transversum's invasion by hepatic cords. ## Frequently asked questions ### Which structures enter or leave at the porta hepatis? The portal vein, hepatic artery proper, right and left hepatic ducts, lymphatics and autonomic nerves — the portal triad plus its companions. ### What are the boundaries and contents of Calot's triangle? Cystic duct inferiorlaterally, common hepatic duct medially and the liver surface superiorly; it contains the cystic artery, cystic lymph node and sometimes an aberrant right hepatic artery. ### What is Cantlie's line and which segments lie on each side? The functional dividing plane from the gallbladder bed to the IVC along the middle hepatic vein; segments 2, 3 and 4 (with 1) lie to the left, segments 5–8 to the right. ### Why does the caudate lobe hypertrophy in Budd-Chiari syndrome? Its veins drain directly into the inferior vena cava, so hepatic vein obstruction sparing the caudate outflow leaves it functioning and enlarging while the rest of the liver congests. ### What is the Pringle manoeuvre and what bleeding does it control? Digitally compressing the portal triad in the free edge of the lesser omentum; it controls hepatic arterial and portal venous bleeding, but not retrohepatic vena caval haemorrhage.