Liver Anatomy, Parts, Names & Diagram

Liver Anatomy – Complete Guide with Parts, Names, Functions & Diagram

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Overview of Liver Anatomy and Physiology

The liver is a vital organ found only in vertebrate animals. It plays a key role in keeping the body healthy by detoxifying harmful substances, producing proteins, and making essential chemicals needed for digestion and growth. In humans, the liver is located in the upper right part of the abdomen, just below the diaphragm and behind the lower ribs. Its function is to process carbohydrates, store energy as glycogen, and regulate blood sugar levels. It also helps break down old red blood cells and produces hormones. As part of the digestive system, the liver creates bile, a fluid that helps digest fats. This bile is stored in the gallbladder, a small pouch beneath the liver, and released into the small intestine when needed for digestion. Liver anatomy consists of two main sections, called lobes, but it’s much more than that. It is made up of many parts that handle over 300 important jobs for your body.

In this article, we will explore the liver anatomy with its position in the body, its structure, and how it is supplied with blood and nerves.

Liver Anatomy Diagram

Liver Anatomy, Parts, Names & Diagram

Anatomy of the Liver

External Liver Anatomy

  1. Lobes of the Liver
    • Right Lobe
    • Left Lobe
    • Caudate Lobe
    • Quadrate Lobe
  2. Surface Anatomy
    • Diaphragmatic Surface
    • Visceral Surface
  3. Ligaments
    • Falciform Ligament
    • Coronary Ligaments
    • Triangular Ligaments
    • Lesser Omentum
  4. Hepatic Recesses

Liver Segmental Anatomy

  1. Segments Based on Vertical Planes
    • Plane of Right Hepatic Vein
    • Plane of Middle Hepatic Vein
    • Umbilic Plane
  2. Functional Segmental Liver Anatomy
    • Portal Vein
    • Left Hepatic Vein
  3. Actual Segmental Liver Anatomy

Internal Liver Anatomy

  1. Blood Supply
  2. Nerve Supply
  3. Lymphatic drainage

External Liver Anatomy

The liver, the body’s largest gland, is a vital organ with distinct external features. It is located in the upper right portion of the abdominal cavity, beneath the diaphragm. This organ has a smooth, reddish-brown surface, divided into right & left lobes and different ligaments. These external structures enable the liver to carry out essential functions like detoxification, metabolism, and bile production.

Lobes of the Liver

1. Right Lobe

The liver’s right lobe is significantly larger than the left. It occupies most of the right upper abdomen (right hypochondrium). The ligamentum venosum marks its upper boundary, while the round ligament (ligamentum teres hepatis) defines the lower edge.

It curves beneath the liver and continues along the falciform ligament. Functionally, the division between the right and left lobes is determined by the path of the middle hepatic vein.

2. Left Lobe

The left lobe is smaller and flatter than the right. It is in the upper central and left abdomen. Its upper surface curves gently to fit beneath the diaphragm, while the underside features contours matching the stomach and includes a small projection known as the omental tuberosity.

3. Caudate Lobe

The caudate lobe of the liver is situated on the upper back portion of the right lobe, close to the tenth and eleventh thoracic vertebrae. The lobe is positioned vertically, with its length from top to bottom greater than from side to side, and has a slight curvature.

It lies behind the porta hepatis and separates the gall bladder groove from the beginning of the groove for the inferior vena cava. Caudate lobe is surrounded by several key structures:

  • Below it is the porta hepatis, the entrance for blood vessels and ducts.  
  • On its right side, a groove accommodates the inferior vena cava.  
  • On the left side, it is bordered by a groove for the ductus venosus and the ligamentum venosum, which help divide the liver.

4. Quadrate Lobe

The quadrate lobe is a specific area of the liver located on the underside of the medial segment of the left lobe (Couinaud segment IVb).

It is bordered in the front by the liver’s anterior edge, in the back by the porta hepatis, on the right by the gallbladder fossa, and the left by the fossa of the umbilical vein. The lobe has an oblong shape, with its front-to-back length greater than its side-to-side width.

Surface Anatomy of the Liver

The liver has two distinct surfaces, each defined by its position and neighboring structures. The diaphragmatic surface lies beneath the diaphragm and conforms to its curved shape, playing a role in separating the liver from the chest cavity.

The visceral surface faces downward and interacts closely with the abdominal organs, such as the stomach, intestines, and gallbladder. These surfaces reflect the liver’s functional and anatomical relationships within the body.

1. Diaphragmatic Surface

The diaphragmatic surface of the liver is the upper front part that lies just below the diaphragm. It has a smooth, curved shape that matches the diaphragm’s contour.

A portion at the back of this surface called the “bare area,” isn’t covered by the protective visceral peritoneum and directly touches the diaphragm.

2. Visceral Surface

The visceral surface of the liver is located on its lower rear side. It is mostly covered by a thin peritoneal membrane, except at the gallbladder’s groove and the porta hepatis. This surface is uneven and shaped by the nearby organs against which it rests.

It directly contacts the right kidney, adrenal gland, right colic flexure of the large intestine, transverse colon, duodenum, gallbladder, esophagus, and stomach. This close relationship influences both its shape and function.

Ligaments of the Liver Anatomy

The liver is a vital organ in the abdominal cavity. It is supported and held in place by several ligaments. These structures help stabilize the liver and define its connections with surrounding organs and tissues.

1. Falciform Ligament

The falciform ligament is a thin, sickle-shaped tissue band that connects the front surface of the liver to the inner side of the abdominal wall. At its free edge lies the ligamentum teres (round ligament), a remnant of the umbilical vein from fetal development.

2. Coronary Ligament

This ligament attaches the top surface of the liver to the diaphragm, the muscle that helps us breathe. It has two layers—anterior and posterior—surrounding a part of the liver called the bare area, which lacks a protective covering. The ends of the coronary ligament extend to form the triangular ligaments.

3. Triangular Ligaments

  • The left Triangular Ligament is found where the two layers of the coronary ligament meet on the left side, anchoring the left lobe of the liver to the diaphragm.
  • The right Triangular Ligament is formed similarly on the right side. This ligament secures the liver’s right lobe to the diaphragm.

4. Lesser Omentum

The lesser omentum is a tissue sheet that connects the liver to the stomach and the beginning of the small intestine (duodenum). It has two main parts:

  • Hepatoduodenal Ligament: This ligament links the liver to the duodenum and surrounds the portal triad, which includes the hepatic artery, portal vein, and bile duct.
  • Hepatogastric Ligament: It connects the liver to the stomach.

Hepatic Recesses

The hepatic recesses are anatomical spaces situated between the liver and nearby structures. They play a critical role in clinical medicine as they can harbor infections, leading to abscess formation.

  • Subphrenic spaces: These lie between the diaphragm and the liver’s anterior and superior surfaces. The falciform ligament divides them into right and left sections.
  • Subhepatic space: This area is located between the liver’s underside and the transverse colon and is found within the supracolic compartment, above the transverse mesocolon.
  • Morison’s pouch: Positioned between the liver’s visceral surface and the right kidney, this is the lowest point of the peritoneal cavity when lying flat. It often becomes a collection site for pathological fluids, such as blood or ascites, in bedridden patients.

Liver Segmental Anatomy (Couinaud Classification)

The Couinaud classification organizes the liver into eight self-contained segments, each with its own unique blood supply, bile drainage, and venous outflow.

Within the core of each segment, branches of the portal vein, hepatic artery, and bile duct work together to support its function.

At the segment boundaries, the hepatic veins carry blood away, ensuring efficient circulation. This segmentation highlights the liver’s remarkable ability to function independently across its regions.

Segments Based on Vertical Planes

  • The right hepatic vein separates the right lobe of the liver into two parts: the anterior and posterior segments.
  • The middle hepatic vein divides the liver into right and left halves (hemiliver). This division stretches from the inferior vena cava to the gallbladder fossa.
  • The umbilical plane, which runs from the falciform ligament to the inferior vena cava, splits the left lobe into two sections. The medial section corresponds to segment IV, while the lateral section includes segments II and III. Unlike the other divisions, this plane is not aligned with a hepatic vein.

Functional Segmental Liver Anatomy

1. Portal Vein

The portal vein is essential for dividing the liver into upper and lower sections. Its left and right branches stretch upwards and downwards, ensuring blood is delivered efficiently to the center of each liver segment.

2. Left Hepatic Vein

The exact position of the left hepatic vein is still debated. While some believe it follows the umbilical fissure, most evidence shows it lies slightly to the side of this landmark.

The division between segments II and III of the liver is also a topic of discussion. While some say it is defined by the horizontal plane of the left portal vein, most experts agree that it follows the path of the left hepatic vein.

In surgery, removing the lateral part of the left lobe (segments II and III) is called a left lateral segmentectomy. This procedure is generally guided by the plane of the umbilical fissure.

Actual Segmental Liver Anatomy

The liver is divided into sections based on its functional anatomy, following Couinaud’s classification, instead of using external landmarks. The functional right and left lobes are separated by an imaginary line called Cantlie’s line.

This line runs from the front of the liver, near the gallbladder, to the back, reaching the inferior vena cava, following the path of the middle hepatic vein.

When viewed from the front, segments VI and VII are not visible because they are located at the back of the liver.

Segments V and VIII shape the right edge, while segment IV, though part of the left lobe, appears closer to the right side in this view. The actual sizes and positions of these segments are more complex than shown in basic diagrams.

Internal Liver Anatomy

Blood Supply

The liver is a remarkable organ because it receives most of its blood supply from veins rather than arteries. This blood comes through the portal vein, which carries nutrient-rich blood from the gastrointestinal tract, where nutrients are absorbed.

The remaining blood supply comes from the common hepatic artery, which delivers oxygenated blood to the liver from the celiac trunk.

Inside the liver, blood is cleaned and detoxified. The purified blood then exits the liver through the hepatic veins.

These veins form by joining smaller central veins and carry the blood directly into the inferior vena cava, which takes it to the heart after passing through the diaphragm.

Nerve Supply

The working part of the liver called the parenchyma, gets its nerve supply from the hepatic plexus. This plexus brings in sympathetic nerves from the celiac plexus and parasympathetic nerves from the vagus nerve.

These nerves enter the liver through the porta hepatis and follow the hepatic artery and portal vein branches.
The liver’s outer covering, known as Glisson’s capsule, is connected to the lower intercostal nerves. When this capsule is stretched, it can cause a sharp, pinpointed pain.

Lymphatic Drainage

The liver’s lymphatic drainage is divided into two distinct systems:

1. Deep Lymphatic

The deep lymphatic system consists of vessels that accompany the hepatic portal veins. Most lymph from this system flows to the hepatic lymph nodes near the liver’s hilum. These nodes further channel lymph to the celiac lymph nodes, transporting it to the cisterna chyli (if present) and the thoracic duct.

2. Superficial Lymphatic

The superficial lymphatic system drains the liver’s outer covering, known as Glisson’s capsule, with specific pathways for different surfaces:

  • The anterior, superior, and inferior surfaces primarily direct lymph to hepatic lymph nodes at the porta hepatis.
  • The inferior surface may also send lymph directly to the lumbar lymph nodes.
  • The superior surface connects to parasternal or pericardiac lymph nodes.
  • The posterior surface routes lymph to celiac, superior mesenteric, or posterior mediastinal lymph nodes.

This intricate network ensures lymph from all parts of the liver is efficiently collected and filtered, playing a vital role in immune defense and fluid balance.

Read More-

Lower Limb

Upper Limb

Human Head

Organs

External Sources-

  • Wikipedia
  • KenHub
  • Optometrists
  • Cleveland Clinic
  • American Academy of Ophthalmology

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