Right Lobe of the Liver

The right lobe of the liver is the largest of the liver’s anatomical divisions, occupying the majority of the right hypochondrium and extending into the epigastric region. It forms the bulk of the liver’s mass and is separated from the left lobe by both external surface landmarks and internal vascular structures. This lobe is crucial in metabolic processing, bile production, and vascular filtering, and plays a central role in liver resections, segmental anatomy, and pathology localization. Understanding the right lobe's boundaries, segmental divisions, relationships, and function is essential in both anatomical education and clinical hepatobiliary practice.

Structure

The right lobe is defined based on surface anatomy, internal segmental anatomy (Couinaud classification), and vascular supply. While traditionally divided from the left lobe by the falciform ligament, modern anatomical understanding uses portal and hepatic venous structures to delineate functional lobes.

Surface Boundaries

• Anteriorly: Extends from the midline (falciform ligament) to the right lateral abdominal wall.
• Posteriorly: Bounded by the groove for the inferior vena cava and bare area of the liver.
• Inferiorly: Contacts the hepatic flexure of the colon, duodenum, right kidney, and gallbladder fossa.
• Superiorly: Fits under the right hemidiaphragm and reflects onto the diaphragm at the coronary ligament.

Segmental Division (Couinaud Classification)

The right lobe is subdivided into four segments based on portal vein and hepatic vein branching:

Segment Number	Segment Name	Description
V	Inferior anterior	Located anterior to the right portal vein; lies adjacent to the gallbladder fossa
VI	Inferior posterior	Lies below the horizontal part of the right portal vein and posterior to segment V
VII	Superior posterior	Posterior and superior to the right hepatic vein; contacts the diaphragm
VIII	Superior anterior	Superior to segment V and anterior to the right hepatic vein

These segments are divided vertically by hepatic veins and horizontally by the portal vein bifurcation. Segment VIII is the highest and most anterior part of the right lobe.

Major Features on Visceral Surface

• Gallbladder fossa: A shallow depression where the gallbladder lies.
• Impression from right kidney: On the posteroinferior surface.
• Bare area: Part of the liver not covered by peritoneum, in direct contact with the diaphragm.

Location

The right lobe occupies the right hypochondrium and part of the epigastric region. Its superior border lies deep to ribs 5 through 8 on the right side. The lobe extends below the costal margin during inspiration, especially in thin individuals.

Topographic Relationships

• Superior: Diaphragm, right pleura, and lung (posteriorly)
• Inferior: Right kidney, hepatic flexure of colon, duodenum
• Anterior: Abdominal wall, peritoneum
• Posterior: Right adrenal gland, diaphragm, IVC groove

Because of its size and surface area, the right lobe forms impressions on multiple adjacent organs, particularly visible in cadaveric dissection and imaging.

Function

The right lobe, like the rest of the liver, performs a broad range of essential functions related to metabolism, detoxification, immune support, and bile production. Due to its size, it handles a disproportionately large share of these processes. Below is a categorized list of its functional roles:

Metabolic Functions

• Carbohydrate storage (as glycogen) and gluconeogenesis
• Lipid metabolism including cholesterol and lipoprotein synthesis
• Protein synthesis (e.g., albumin, clotting factors)

Detoxification and Filtration

• Metabolism of drugs and xenobiotics via cytochrome P450 enzymes
• Conversion of ammonia to urea
• Filtration of blood from the gastrointestinal tract via the portal system

Bile Production and Excretion

• Synthesis of bile salts and secretion into canaliculi
• Contributes significantly to daily bile output (500–1000 mL/day)

Immune and Storage Functions

• Phagocytosis of pathogens by Kupffer cells in sinusoids
• Storage of iron (in ferritin), copper, and fat-soluble vitamins (A, D, E, K)

Clinical Relevance

The right lobe of the liver is involved in many common clinical conditions and is frequently the focus in diagnostic imaging and surgical procedures.

Common Pathologies

• Right lobe hepatocellular carcinoma: More frequent due to larger volume and greater exposure to portal flow
• Liver abscess: Often forms in segment VI or VII due to gravity-dependent positioning and portal venous drainage
• Cystic lesions: Simple hepatic cysts, hydatid disease, or polycystic liver disease are commonly detected in the right lobe via ultrasound or CT

Surgical Relevance

In hepatic resections, the right lobe may be removed partially (e.g., right hepatectomy) or segmentally (e.g., resection of segments VI–VII). Understanding its vascular inflow (right portal vein, right hepatic artery) and outflow (right hepatic vein) is crucial. Misidentification of segmental anatomy can result in bleeding or bile leaks.

Imaging Landmarks

In cross-sectional imaging:

• The right lobe is demarcated from the left lobe by the middle hepatic vein and main portal fissure.
• The gallbladder fossa marks the inferior medial surface of segment V.
• Segment VII lies posteriorly and superiorly, making it difficult to visualize on ultrasound.