Liver

Hepar

The largest internal organ and gland, filling the upper right abdomen under the diaphragm and handling much of the body's metabolism.

At a glance

English: Liver
Latin (TA2): Hepar
System: Digestive
Region: Abdomen
Side: Single, on the midline

About the liver

The liver is a wedge-shaped organ weighing about 1.5 kg in an adult. It sits mostly in the right hypochondrium and epigastrium, tucked under the right dome of the diaphragm and protected by the lower ribs, with its thin left end reaching into the left upper abdomen. It has two surfaces: a smooth, domed diaphragmatic surface facing up, forwards, right and back, and a flatter visceral surface facing down and back towards the stomach, duodenum, colon and right kidney. A sharp inferior border separates them in front.

Peritoneum covers most of it and forms the falciform ligament, the coronary and triangular ligaments that tie it to the diaphragm, and the lesser omentum that joins it to the stomach. On the surface the falciform ligament and its fissures mark right and left anatomical lobes, with the small caudate and quadrate lobes between them below. Functionally, though, the organ is divided by its blood supply: the main portal fissure, a plane joining the gallbladder bed with the inferior vena cava, separates right and left parts, each with its own branch of the hepatic artery, portal vein and bile duct. These parts are split further into eight segments, each of which can be removed on its own.

The liver receives about three-quarters of its blood from the portal vein, carrying nutrients from the gut, and the rest from the hepatic artery. Its cells make bile, store glycogen and release glucose, build plasma proteins such as albumin and clotting factors, process fats, and break down drugs, alcohol, hormones and old red cells. Blood leaves through the hepatic veins straight into the inferior vena cava.

Long-term damage from alcohol, fatty liver disease or viral hepatitis can lead to scarring (cirrhosis). This raises portal pressure, opening collateral channels such as varices at the lower oesophagus, and reduces the liver's ability to make proteins and clear bilirubin, so jaundice, fluid in the abdomen and bleeding follow. Because the liver regenerates well, large parts can be resected, and a single segment pair can be transplanted from a living donor.

Function and supply

Function: Makes bile, regulates blood glucose and lipids, synthesises plasma proteins and clotting factors, stores vitamins and iron, and detoxifies drugs and metabolic waste.
Nerve supply: Hepatic plexus from the coeliac plexus with vagal fibres; the capsule and nearby peritoneum are supplied by the lower intercostal and right phrenic nerves, so liver capsule pain may be felt at the right shoulder.
Blood supply: Dual supply from the portal vein (about 75%) and the hepatic artery proper (about 25%); drainage by the right, middle and left hepatic veins into the inferior vena cava.

Parts of the liver

Each number is marked on the model. Press one, here or on the model, to see it named in place.

Anterior lateral segment of liver (VISegment VI, the lower outer part of the right lateral division, lying below segment VII along the right inferior border. It touches the hepatic flexure of the colon and the right kidney.
Anterior medial segment of liver (VSegment V, the lower part of the right medial division, lying just right of the gallbladder bed. It is often removed together with the gallbladder in cancers of that organ.
Anterior surface of liverFacies anterior hepatisThe front-facing part of the diaphragmatic surface, lying behind the costal margin and the upper front abdominal wall. The falciform ligament attaches to it.
Bare area of liverArea nuda hepatisA triangular patch on the back of the right lobe with no peritoneal covering, held directly against the diaphragm by connective tissue. The coronary ligament layers outline it, and the inferior vena cava lies in a groove at its left end.
Cardiac impression of liverImpressio cardiaca hepatisA shallow hollow on the upper surface, mostly on the left lobe, where the heart rests on the diaphragm above. It lies beneath the central tendon and pericardium.
Caudate lobeLobus caudatusA small lobe on the back of the liver between the inferior vena cava and the fissure for the ligamentum venosum. It is fed by both portal branches and drains directly into the vena cava, so it is often spared in diseases that block the main hepatic veins.
Colic impression of liverImpressio colica hepatisA shallow mark on the lower front of the right lobe's visceral surface made by the right colic flexure. It lies on the right side of the gallbladder bed.
Diaphragmatic surface of liverFacies diaphragmatica hepatisThe smooth, convex surface fitting under the diaphragm, divided into superior, anterior, right and posterior parts. Apart from the bare area, it is covered by peritoneum.
Duodenal impression of liverImpressio duodenalis hepatisA mark on the right lobe's visceral surface near the neck of the gallbladder, made by the first part of the duodenum.
Fibrous appendix of liverAppendix fibrosa hepatisA fibrous band, present in some people, at the far left tip of the left lobe, continuous with the left triangular ligament. It is a leftover of liver tissue that has regressed.
Fissure for ligamentum teresFissura ligamenti teretisA groove on the visceral surface, separating the quadrate lobe from the left lobe, that holds the round ligament, the remnant of the umbilical vein. It runs from the inferior border back to the porta hepatis.
Fissure for ligamentum venosumFissura ligamenti venosiA deep cleft on the back of the visceral surface between the caudate lobe and the left lobe, holding the remnant of the ductus venosus. The lesser omentum attaches in its depth.
Fossa for gallbladderFossa vesicae biliarisA shallow hollow on the visceral surface between the quadrate lobe and the right lobe, in which the gallbladder lies. It marks the front end of the main portal fissure.
Gastric impression of liverImpressio gastrica hepatisA broad concave area on the left lobe's visceral surface where the front of the stomach rests.
Inferior border of liverMargo inferior hepatisThe sharp front edge separating the diaphragmatic and visceral surfaces. It carries notches for the ligamentum teres and the gallbladder fundus and usually follows the right costal margin.
Left anterior lateral segment of liver (IIISegment III, the lower front part of the left lateral division, lying to the left of the falciform ligament. With segment II it is commonly used for transplants to small children.
Left lateral division of liverDivisio lateralis sinistra hepatisThe part of the liver to the left of the umbilical fissure and falciform ligament, made of segments II and III. Its blood and bile run through the left branches.
Left lobe of liverLobus sinister hepatisThe anatomical lobe lying to the left of the falciform ligament and its fissures, flatter and smaller than the right. It reaches across the epigastrium into the left hypochondrium.
Left medial division of liverDivisio medialis sinistra hepatisSegment IV, bounded by the umbilical fissure on its left and the main portal fissure on its right. It is the right-hand part of the functional left liver.
Left medial segment of liver (IVSegment IV, between the falciform ligament and the gallbladder fossa; its lower part (IVb) corresponds to the quadrate lobe and its upper part (IVa) lies near the diaphragm.
Left part of liverPars sinistra hepatisThe functional left liver, to the left of the main portal fissure, made of the left medial and left lateral divisions. It receives the left branches of the hepatic artery and portal vein.
Left posterior lateral segment of liver (IISegment II, the upper back part of the left lateral division, reaching towards the left triangular ligament.
Main portal fissureFissura portalis principalisThe plane, marked by the middle hepatic vein, running from the gallbladder fossa back towards the inferior vena cava; it separates the functional right and left parts of the liver, not the anatomical lobes.
Notch for ligamentum teresIncisura ligamenti teretisA notch in the inferior border where the round ligament, in the free edge of the falciform ligament, enters the liver.
Oesophageal impression of liverImpressio oesophagea hepatisA small groove on the back of the left lobe, near the fissure for the ligamentum venosum, made by the abdominal part of the oesophagus.
Omental tuberosity of liverTuber omentale hepatisA rounded bulge on the left lobe's visceral surface, beside the fissure for the ligamentum venosum. It faces the lesser omentum and the stomach's lesser curvature.
Papillary processProcessus papillarisA small rounded projection from the lower left part of the caudate lobe. On scans it can be mistaken for an enlarged lymph node or a mass.
Porta hepatisThe transverse fissure on the visceral surface between the caudate and quadrate lobes, the hilum of the liver. The portal vein, hepatic artery proper and nerve plexus enter and the hepatic ducts and lymphatics leave here.
Posterior medial segment of liver (VIIISegment VIII, the upper part of the right medial division, high under the diaphragm beside the inferior vena cava. It is drained by the middle and right hepatic veins.
Posterior part of liverPars posterior hepatisThe caudate lobe considered as a separate functional unit (segment I). It receives branches from both sides and drains straight into the inferior vena cava.
Posterior segment of liver (ISegment I, equivalent to the caudate lobe, lying in front of the inferior vena cava. Its independent supply and drainage set it apart from the other seven segments.
Posterior surface of liverFacies posterior hepatisThe back-facing part of the diaphragmatic surface, containing the bare area, the groove for the inferior vena cava and the caudate lobe.
Quadrate lobeLobus quadratusA small rectangular lobe on the visceral surface, bounded by the gallbladder fossa, the fissure for the ligamentum teres and the porta hepatis. Functionally it is part of segment IV (IVb).
Renal impression of liverImpressio renalis hepatisA hollow on the back of the right lobe's visceral surface where the upper part of the right kidney lies, extending up to the bare area.
Right lateral division of liverDivisio lateralis dextra hepatisThe part of the right liver lateral to the right portal fissure, made of segments VI and VII.
Right lobe of liverLobus dexter hepatisThe large anatomical lobe to the right of the falciform ligament and its fissures, making up most of the liver mass. It bears the impressions of the colon, kidney, adrenal and duodenum.
Right medial division of liverDivisio medialis dextra hepatisThe part of the right liver bounded by the main and right portal fissures, made of segments V and VIII.
Right part of liverPars dextra hepatisThe functional right liver, on the far side of the main portal fissure from the left part, made of the right medial and right lateral divisions. It is supplied by the right branches of the hepatic artery and portal vein.
Right portal fissureFissura portalis dextraThe plane of the right hepatic vein, dividing the right part of the liver into medial and lateral divisions. It has no visible surface marking.
Right surface of liverFacies dextra hepatisThe part of the diaphragmatic surface facing to the right, lying against the diaphragm opposite the seventh to eleventh ribs.
Superior surface of liverFacies superior hepatisThe upper, domed part of the diaphragmatic surface, under both domes of the diaphragm. It carries the cardiac impression in its middle.
Suprarenal impression of liverImpressio suprarenalis hepatisA small triangular mark on the bare area, just to the right of the inferior vena cava, made by the right adrenal gland.
Umbilical fissureFissura umbilicalisThe left portal fissure, lying along the falciform ligament and the fissure for the ligamentum teres. It separates the left medial division (IV) from the left lateral division (II and III).
Visceral surface of liverFacies visceralis hepatisThe irregular lower and back surface facing the abdominal organs, which leave impressions on it. It carries the porta hepatis and gallbladder fossa and is covered with peritoneum except at those sites.

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At a glance

About the liver

Function and supply

Related structures

See the liver where it really sits, with every layer of the body around it.