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Lobes of the Liver
The liver is anatomically divided into right, left, caudate, and quadrate lobes by surface landmarks including the falciform ligament, fissures, gallbladder fossa, and groove for the inferior vena cava. Functional hepatic division differs from this traditional morphological arrangement.
RegionAbdomen
SystemDigestive System
The liver is the largest solid visceral organ in the body and occupies much of the right upper abdomen. Traditionally, its external anatomy is divided into four morphological lobes: the right lobe, left lobe, caudate lobe, and quadrate lobe.
These anatomical lobes are defined primarily by landmarks visible on the diaphragmatic and visceral surfaces of the liver. The falciform ligament provides the principal superficial division between the right and left lobes on the diaphragmatic surface, while fissures, fossae, and vascular grooves define the caudate and quadrate lobes on the visceral surface.
The traditional morphological division does not correspond completely to the liver's internal vascular and biliary organization. In functional and surgical anatomy, the liver is divided according to the distribution of the portal vein, hepatic artery, bile ducts, and hepatic veins.
Anatomical Lobes of the Liver
The four traditionally described anatomical lobes are:
- Right lobe
- Left lobe
- Caudate lobe
- Quadrate lobe
The right and left lobes are readily visible from the diaphragmatic surface, while the caudate and quadrate lobes are defined most clearly on the visceral surface.
Right Lobe
The right lobe is the largest anatomical lobe of the liver. It occupies most of the right hypochondrium and extends medially into the epigastric region.
It is considerably larger and thicker than the anatomical left lobe.
Position of the Right Lobe
The right lobe lies primarily beneath the right dome of the diaphragm.
Its superior surface conforms closely to the inferior surface of the diaphragm and therefore indirectly relates to the right pleural cavity and right lung.
Anterior Surface of the Right Lobe
Anteriorly, the right lobe lies deep to the lower ribs and costal cartilages and extends toward the anterior abdominal wall.
The falciform ligament marks its superficial boundary with the left lobe.
Posterior Surface of the Right Lobe
The posterior aspect of the right lobe includes the large bare area of the liver, where the liver is directly related to the diaphragm without an intervening peritoneal covering.
This region is bounded by reflections of the coronary ligament.
Visceral Surface of the Right Lobe
The visceral surface of the right lobe is related to several abdominal structures and contains impressions produced by neighboring organs.
Important relationships include the right kidney, right suprarenal gland, duodenum, hepatic flexure of the colon, and gallbladder.
Renal Impression
The renal impression is produced by the relationship between the visceral surface of the right hepatic lobe and the superior portion of the right kidney.
Suprarenal Impression
The right suprarenal gland lies between the liver and diaphragm near the posterior aspect of the right lobe.
Its relationship can produce a suprarenal impression on the hepatic surface.
Duodenal Impression
The superior part of the duodenum is related to the visceral surface of the liver near the gallbladder and porta hepatis.
This relationship contributes to the duodenal impression.
Colic Impression
The right colic flexure and adjacent transverse colon are related to the inferior aspect of the right hepatic lobe.
This relationship forms the colic impression.
Left Lobe
The left lobe is smaller and thinner than the right lobe and extends across the epigastric region toward the left hypochondrium.
Its tapered left extremity may extend toward the spleen.
Position of the Left Lobe
The left lobe lies largely beneath the diaphragm and extends across the midline.
It overlies portions of the stomach and abdominal esophagus.
Diaphragmatic Surface of the Left Lobe
On the diaphragmatic surface, the falciform ligament provides the visible anatomical boundary between the right and left lobes.
The left lobe lies to the left of this ligament.
Visceral Surface of the Left Lobe
The visceral surface of the left lobe is related predominantly to the stomach and abdominal esophagus.
These relationships produce recognizable impressions on the liver.
Gastric Impression
The gastric impression occupies a substantial portion of the visceral surface of the left lobe.
It reflects the close relationship between the liver and anterior-superior surface of the stomach.
Esophageal Impression
A shallow esophageal impression may be present near the posterior aspect of the left lobe where the abdominal esophagus approaches the stomach.
Right and Left Anatomical Lobes
| Feature | Right Lobe | Left Lobe |
|---|---|---|
| Relative size | Larger and thicker | Smaller and thinner |
| Main location | Right hypochondrium and epigastrium | Epigastrium and left hypochondrium |
| Superficial boundary | Falciform ligament on diaphragmatic surface | |
| Major visceral relationships | Kidney, suprarenal gland, duodenum and colon | Stomach and esophagus |
Falciform Ligament
The falciform ligament is a double layer of peritoneum connecting the liver to the anterior abdominal wall and inferior surface of the diaphragm.
On the diaphragmatic surface, it provides the traditional morphological division between the right and left hepatic lobes.
Free Margin of the Falciform Ligament
The free inferior margin of the falciform ligament contains the round ligament of the liver, or ligamentum teres hepatis.
This fibrous structure is a remnant of the fetal umbilical vein.
Ligamentum Teres
The ligamentum teres travels within the free margin of the falciform ligament toward the visceral surface of the liver.
It occupies the fissure for the ligamentum teres, an important landmark separating portions of the anatomical left and quadrate lobes.
Visceral Surface
The visceral surface of the liver contains several prominent grooves, fissures, and fossae arranged around the porta hepatis.
These landmarks create an approximately H-shaped configuration and define the caudate and quadrate lobes.
H-Shaped Arrangement
The traditional H-shaped arrangement on the visceral surface consists of right and left sagittal grooves connected by the transverse porta hepatis.
The structures forming these grooves include the gallbladder fossa, groove for the inferior vena cava, fissure for the ligamentum teres, and fissure for the ligamentum venosum.
Left Sagittal Fissure
The left sagittal fissure consists of the fissure for the ligamentum teres anteriorly and the fissure for the ligamentum venosum posteriorly.
These structures help define the left boundaries of the quadrate and caudate lobes.
Right Sagittal Groove
The right side of the H-shaped arrangement is formed by the gallbladder fossa anteriorly and the groove for the inferior vena cava posteriorly.
These landmarks define the right boundaries of the quadrate and caudate lobes.
Porta Hepatis
The porta hepatis is a transverse fissure on the visceral surface of the liver.
It lies between the caudate lobe posteriorly and quadrate lobe anteriorly.
Major branches of the portal vein and hepatic artery enter the liver through the porta hepatis, while hepatic ducts and lymphatic vessels leave it.
Caudate Lobe
The caudate lobe is a distinct anatomical region on the posterior part of the visceral surface of the liver.
It lies superior to the porta hepatis and between the fissure for the ligamentum venosum and the groove for the inferior vena cava.
Boundaries of the Caudate Lobe
| Boundary | Structure |
|---|---|
| Anterior | Porta hepatis |
| Left | Fissure for ligamentum venosum |
| Right | Groove for inferior vena cava |
| Superior | Posterior hepatic surface approaching the diaphragm |
Caudate Process
The caudate process is a narrow bridge of hepatic tissue extending from the caudate lobe toward the right lobe.
It passes between the porta hepatis and the groove for the inferior vena cava.
Papillary Process
The caudate lobe may possess a projecting portion known as the papillary process.
Its size and prominence vary considerably between individuals.
Vascular Features of the Caudate Lobe
The caudate lobe is distinctive because it can receive portal venous and arterial branches from both right and left hepatic vascular territories.
Its hepatic venous drainage frequently passes directly into the adjacent inferior vena cava through small caudate veins.
Functional Independence of the Caudate Lobe
Because of its distinctive vascular inflow and direct venous drainage, the caudate lobe has a degree of functional independence from the remainder of the liver.
This feature is particularly important in hepatic imaging and surgery.
Quadrate Lobe
The quadrate lobe is visible on the inferior part of the visceral surface of the liver.
It lies inferior to the porta hepatis between the gallbladder fossa and fissure for the ligamentum teres.
Boundaries of the Quadrate Lobe
| Boundary | Structure |
|---|---|
| Posterior | Porta hepatis |
| Left | Fissure for ligamentum teres |
| Right | Gallbladder fossa |
| Anterior | Inferior border of liver |
Relationship to the Gallbladder
The gallbladder fossa forms the right boundary of the quadrate lobe.
The gallbladder therefore lies immediately adjacent to the quadrate region of the visceral hepatic surface.
Relationship to the Ligamentum Teres
The fissure containing the ligamentum teres forms the left boundary of the quadrate lobe.
This fissure separates the quadrate lobe morphologically from the anatomical left lobe.
Functional Identity of the Quadrate Lobe
Although the quadrate lobe appears morphologically associated with the anatomical right lobe, its vascular and biliary supply generally associates it functionally with the left liver.
This illustrates the important distinction between morphological and functional hepatic anatomy.
Anatomical Versus Functional Lobes
The anatomical division of the liver is based primarily on external surface landmarks.
The functional division is based on the internal distribution of portal venous inflow, hepatic arterial inflow, and biliary drainage.
Functional Right and Left Liver
Functionally, the liver can be divided into right and left portions by an approximately vertical plane extending from the gallbladder fossa anteriorly toward the inferior vena cava posteriorly.
This plane is commonly associated with the course of the middle hepatic vein.
Cantlie Line
The surface projection of the principal functional division is commonly described by Cantlie's line.
It extends approximately from the gallbladder fossa toward the inferior vena cava and separates the functional right and left hepatic territories.
Falciform Ligament Versus Functional Division
The falciform ligament does not mark the principal internal vascular division of the liver.
Therefore, the anatomical right and left lobes defined externally do not correspond precisely to the functional right and left liver used in modern hepatic surgery.
Morphological and Functional Divisions
| Feature | Morphological Division | Functional Division |
|---|---|---|
| Basis | External surface landmarks | Portal, arterial and biliary distribution |
| Main dividing landmark | Falciform ligament | Plane from gallbladder fossa toward IVC |
| Relationship to middle hepatic vein | Not primary basis | Closely related |
| Surgical relevance | Gross orientation | Major importance in hepatic resection |
Portal Venous Distribution
The portal vein divides near the porta hepatis into right and left branches.
These branches supply functionally distinct regions of hepatic parenchyma and contribute to the internal organization of the liver.
Hepatic Arterial Distribution
The proper hepatic artery typically divides into right and left hepatic arteries near the porta hepatis.
Their branches generally accompany portal venous and biliary branches within the liver.
Biliary Drainage
Intrahepatic bile ducts generally accompany branches of the hepatic artery and portal vein.
They converge into larger ducts that ultimately form the right and left hepatic ducts.
Hepatic Veins
The hepatic veins have an important relationship to functional hepatic anatomy.
The major right, middle, and left hepatic veins occupy planes between major portal territories and drain directly into the inferior vena cava.
Right Hepatic Vein
The right hepatic vein drains much of the functional right liver.
Its course forms an important intersegmental plane within the right hepatic territory.
Middle Hepatic Vein
The middle hepatic vein lies near the principal plane separating the functional right and left liver.
Its position is therefore an important landmark in cross-sectional imaging and hepatic surgery.
Left Hepatic Vein
The left hepatic vein drains substantial portions of the functional left liver.
It often joins the middle hepatic vein before entering the inferior vena cava, although venous anatomy varies.
Couinaud Segmentation
Modern surgical anatomy commonly subdivides the liver into functionally independent regions known as Couinaud segments.
Each major segment has its own portal venous, hepatic arterial, and biliary branches.
Segment I
Segment I corresponds to the caudate lobe.
It is distinctive because of its variable inflow from both sides of the liver and its direct venous drainage into the inferior vena cava.
Left Hepatic Segments
The functional left liver includes segments situated on both sides of the falciform ligament.
This demonstrates why the external anatomical left lobe is not equivalent to the entire functional left liver.
Right Hepatic Segments
The functional right liver is subdivided into anterior and posterior sectors and further into individual segments.
These divisions are based on portal pedicles and hepatic venous planes rather than external fissures alone.
Relationship of the Quadrate Lobe to Segment IV
The traditional quadrate lobe forms part of the functional left liver and corresponds principally to the inferior portion of segment IV.
This is another important difference between external and functional hepatic anatomy.
Relationship of the Caudate Lobe to Segment I
The caudate lobe corresponds to segment I in the Couinaud system.
Its relatively independent vascular arrangement distinguishes it from the other hepatic segments.
Inferior Vena Cava
The inferior vena cava lies in a deep groove on the posterior surface of the liver between the right lobe and caudate lobe.
The close relationship between the liver and IVC is important in both gross anatomy and hepatic surgery.
Groove for the Inferior Vena Cava
The IVC occupies a vertical groove on the posterior hepatic surface.
This groove forms the right boundary of the caudate lobe.
Ligamentum Venosum
The ligamentum venosum is a fibrous remnant of the fetal ductus venosus.
It occupies a fissure on the visceral surface that forms the left boundary of the caudate lobe.
Gallbladder Fossa
The gallbladder occupies a fossa on the visceral surface of the liver.
This fossa forms the right boundary of the quadrate lobe and also contributes to the surface landmark used in defining the functional right-left hepatic division.
Bare Area
The bare area of the liver is a region on the posterior aspect of the right lobe that lacks a peritoneal covering.
It lies directly against the diaphragm and is bounded by layers of the coronary ligament.
Coronary Ligament
The coronary ligament consists of peritoneal reflections between the liver and diaphragm.
Its anterior and posterior layers define the margins of the bare area.
Right Triangular Ligament
At the lateral aspect of the right lobe, the layers of the coronary ligament approach one another to form the right triangular ligament.
This ligament helps attach the right hepatic lobe to the diaphragm.
Left Triangular Ligament
The left triangular ligament is formed by peritoneal reflections at the lateral extremity of the left lobe.
It contributes to fixation of the left hepatic lobe to the diaphragm.
Fibrous Appendix of the Liver
The extreme lateral portion of the left lobe may become thin and fibrous in some individuals.
This variable extension is sometimes referred to as the fibrous appendix of the liver.
Accessory Hepatic Lobes
Small accessory lobes of hepatic tissue may occur as anatomical variations.
They can be attached to the liver by hepatic tissue, connective tissue, or a vascular pedicle.
Riedel Lobe
A Riedel lobe is a tongue-like inferior projection of the right hepatic lobe.
It represents a morphological variation rather than a separate functional hepatic lobe.
Clinical Importance of Riedel Lobe
A prominent Riedel lobe may extend considerably below the usual inferior hepatic margin.
Recognition of this variation can prevent it from being mistaken for pathological hepatomegaly or an abdominal mass.
Lobar Variations
The relative sizes and shapes of hepatic lobes vary considerably among individuals.
Variations may involve elongation, accessory fissures, prominent processes, or unusual proportions of the right and left lobes.
Accessory Fissures
Accessory fissures may occur on the hepatic surface and can subdivide portions of the liver externally.
They do not necessarily correspond to functional vascular boundaries.
Imaging of the Hepatic Lobes
Ultrasound, CT, and MRI can demonstrate the external hepatic lobes and the internal vascular landmarks used to define functional territories.
Cross-sectional imaging is particularly important because internal vascular anatomy cannot be reliably inferred from external lobe boundaries alone.
Ultrasound
Ultrasound can demonstrate hepatic parenchyma, major vessels, gallbladder, and portions of the liver surface.
Portal and hepatic veins provide important landmarks for identifying functional regions.
CT
CT provides detailed visualization of hepatic morphology and vascular anatomy.
Contrast-enhanced CT can demonstrate portal venous branches, hepatic arteries, hepatic veins, and relationships of lesions to functional hepatic segments.
MRI
MRI provides high soft-tissue contrast and detailed characterization of hepatic parenchyma and vascular structures.
It is also useful for assessing the biliary system when combined with magnetic resonance cholangiographic techniques.
Hepatic Resection
Modern hepatic surgery is based predominantly on functional vascular anatomy rather than the traditional external four-lobe division.
Because portal territories have relatively independent vascular and biliary branches, selected portions of the liver can be removed along anatomical planes.
Right Hepatectomy
A functional right hepatectomy removes the functional right portion of the liver according to vascular and biliary anatomy.
Its plane of division is therefore not simply the falciform ligament.
Left Hepatectomy
A functional left hepatectomy similarly follows the internal division between right and left portal territories.
This includes hepatic tissue that may lie anatomically to the right of the falciform ligament.
Segmental Resection
Individual Couinaud segments or groups of segments may be surgically removed because each has relatively independent portal inflow and biliary drainage.
Knowledge of hepatic veins is also essential because these vessels frequently define intersegmental planes.
Caudate Lobectomy
Resection of the caudate lobe can be technically challenging because of its deep posterior position and close relationship to the inferior vena cava, porta hepatis, and major hepatic vessels.
Its short hepatic veins frequently drain directly into the IVC.
Liver Transplantation
Functional hepatic anatomy is essential in liver transplantation, particularly in living-donor procedures where only a portion of the liver may be transplanted.
Accurate understanding of portal, arterial, biliary, and hepatic venous anatomy is required to preserve viable hepatic territories.
Lobar Enlargement and Atrophy
Changes in portal blood flow, biliary obstruction, chronic liver disease, or vascular disease can produce selective enlargement or atrophy of hepatic regions.
Recognition of these patterns can provide important information on cross-sectional imaging.
Caudate Lobe Enlargement
The caudate lobe may become relatively enlarged in some chronic liver diseases.
Its distinctive vascular supply and direct venous drainage are important anatomical factors in understanding this pattern.
Liver Lobes and Surface Anatomy
| Lobe | Location | Major Boundaries or Landmarks |
|---|---|---|
| Right lobe | Predominantly right side of liver | Falciform ligament provides superficial separation from left lobe |
| Left lobe | Extends across epigastrium toward left hypochondrium | Falciform ligament and left sagittal fissure |
| Caudate lobe | Posterior visceral surface | Porta hepatis, ligamentum venosum fissure and IVC groove |
| Quadrate lobe | Inferior visceral surface | Porta hepatis, gallbladder fossa and ligamentum teres fissure |
Caudate and Quadrate Lobes
| Feature | Caudate Lobe | Quadrate Lobe |
|---|---|---|
| Position relative to porta hepatis | Posterior and superior | Anterior and inferior |
| Left boundary | Ligamentum venosum fissure | Ligamentum teres fissure |
| Right boundary | IVC groove | Gallbladder fossa |
| Functional relationship | Relatively independent, segment I | Primarily functional left liver, segment IV territory |
Key Landmarks of the Liver Lobes
| Landmark | Anatomical Importance |
|---|---|
| Falciform ligament | Separates anatomical right and left lobes on diaphragmatic surface |
| Porta hepatis | Separates caudate and quadrate lobes |
| Gallbladder fossa | Right boundary of quadrate lobe |
| IVC groove | Right boundary of caudate lobe |
| Ligamentum teres fissure | Left boundary of quadrate lobe |
| Ligamentum venosum fissure | Left boundary of caudate lobe |
| Cantlie line | Approximate surface plane between functional right and left liver |
Key Features of the Liver Lobes
| Feature | Key Point |
|---|---|
| Traditional number of anatomical lobes | Four |
| Largest anatomical lobe | Right lobe |
| Smaller major lobe | Left lobe |
| Posterior visceral lobe | Caudate lobe |
| Inferior visceral lobe | Quadrate lobe |
| External right-left landmark | Falciform ligament |
| Functional right-left division | Plane from gallbladder fossa toward IVC |
| Caudate segment | Couinaud segment I |
| Quadrate functional territory | Primarily segment IV |
Anatomical and Clinical Importance
The traditional division of the liver into right, left, caudate, and quadrate lobes provides a useful description of its external morphology. These lobes are defined by visible landmarks including the falciform ligament, porta hepatis, gallbladder fossa, inferior vena cava groove, and fissures containing the ligamentum teres and ligamentum venosum.
Functional hepatic anatomy differs substantially from this external arrangement. The true functional division between the right and left liver follows the internal distribution of portal venous, hepatic arterial, and biliary branches and lies approximately along a plane extending from the gallbladder fossa toward the inferior vena cava. The middle hepatic vein lies close to this plane.
This distinction is particularly important in modern clinical anatomy. Hepatic imaging, segmental resection, transplantation, and other hepatobiliary procedures rely primarily on functional vascular territories rather than the traditional surface lobes. The caudate lobe is especially distinctive because of its relatively independent vascular supply and direct venous drainage into the inferior vena cava.
Published on September 29, 2026
Last updated on September 29, 2026
Last updated on September 29, 2026