Lung Lobes and Fissures Anatomy Vector

Lung Lobes and Fissures: An Overview (2024)

by | Updated: Dec 12, 2023

Lung lobes and fissures play a fundamental role architecture of the human respiratory system.

These structures not only demarcate the lungs’ anatomical divisions but also facilitate their essential function in gas exchange.

Understanding the configuration of lung lobes and fissures is crucial for comprehending how the lungs operate and how various respiratory diseases affect them.

This article explains the detailed anatomy of the lung lobes and fissures, highlighting their significance in both health and pathology.

Lung Lobes and Fissures

The human lungs consist of five lobes, divided by fissures. The right lung has three lobes: the superior, middle, and inferior, separated by the horizontal and oblique fissures. The left lung has two lobes, the superior and inferior, separated by the oblique fissure.

Lung Lobes and Fissures Labeled Illustration

Lung Lobes

A lung lobe is a large, distinct section of a lung, anatomically separated from other lobes by fissures. In humans, each lung is divided into lobes to increase its efficiency in gas exchange.

The right lung has three lobes – superior, middle, and inferior – while the left lung has two lobes – superior and inferior.

These lobes are made up of smaller segments called bronchopulmonary segments, which provide a systematic way for air to be distributed and exchanged in the lungs.

Lung Fissures

A lung fissure is a deep groove or cleft that separates the lobes of the lungs. In the human respiratory system, these fissures allow each lung to be divided into distinct lobes, facilitating efficient functioning and movement.

There are two types of fissures:

  • Oblique Fissure: Present in both lungs, it separates the superior and inferior lobes. In the right lung, it also separates the inferior lobe from the middle lobe.
  • Horizontal Fissure: Only found in the right lung, it divides the superior lobe from the middle lobe.

These anatomical separations are important for both the organization of the bronchial tree and blood vessels, as well as for surgical procedures involving the lungs.

Anatomy of the Lungs

The anatomy of the lungs is intricate and designed for efficient gas exchange, crucial for respiration.

Here’s a general overview:

Right Lung

The right lung, larger and heavier than the left, is divided into three lobes – superior, middle, and inferior – by two major fissures.

  • Superior Lobe: The topmost lobe, located just below the clavicle. It houses the apical segment, which is crucial for upper respiratory functions.
  • Middle Lobe: Smaller and wedged between the superior and inferior lobes. Unique to the right lung, it plays a key role in ventilating the middle region of the thoracic cavity.
  • Inferior Lobe: The largest lobe, occupying the bottom part of the lung. It extends from the base of the lung up to the oblique fissure.

The right lung is characterized by its broader and shorter structure due to the liver’s position beneath it. It contains three fissures:

  • Oblique Fissure: Separates the inferior lobe from the superior and middle lobes.
  • Horizontal Fissure: Divides the superior and middle lobes.

The bronchial tree of the right lung is more vertical and wider than the left, making it more prone to inhaled objects getting trapped.

Left Lung

The left lung is smaller due to the heart’s placement in the thoracic cavity and is divided into two lobes – superior and inferior – by a single oblique fissure.

  • Superior Lobe: Extends from the top of the lung to the oblique fissure. It includes the lingula, a tongue-like projection that corresponds to the middle lobe of the right lung.
  • Inferior Lobe: The larger lobe, occupying the lower half of the left lung. It is involved in the lower respiratory functions.

The left lung has a notable feature called the cardiac notch, an indentation on the lung’s surface to accommodate the heart.

The bronchial tree in the left lung is more horizontal and narrower than in the right, influencing the pattern of air flow and distribution.

Note: Both lungs share similarities in their structure and function, with the main differences arising from their adaptation to accommodate other organs in the thoracic cavity.

FAQs About Lung Lobes and Fissures

What is the Difference Between a Fissure and a Lobe?

A fissure in the lungs is a deep groove or cleft that separates the lobes, which are large, distinct sections of the lung.

Fissures provide anatomical boundaries, while lobes are the functional units of the lungs, each consisting of bronchial trees and alveoli for gas exchange.

Which Lung Has Two Fissures and Three Lobes?

The right lung has two fissures and three lobes.

The fissures are the oblique and horizontal fissures, and the lobes are the superior, middle, and inferior lobes.

What is the Main Fissure of the Lungs?

The main fissure of the lungs is the oblique fissure. It is present in both the right and left lungs, dividing the superior and inferior lobes.

In the right lung, it also separates the inferior lobe from the middle lobe.

What is the Fissure of the Left Lung?

The left lung only has one fissure, the oblique fissure, which separates the superior and inferior lobes. Unlike the right lung, the left lung does not have a horizontal fissure.

What is a Pleural Fissure?

A pleural fissure typically refers to an incidental finding in lung imaging, resembling a lung fissure but not a standard anatomical feature.

It often appears as a thin, linear shadow on radiographs or CT scans, usually resulting from the folding of the pleura or adjacent anatomical structures.

This term is used to describe these pseudo-fissures, which are different from the true fissures that separate the lobes of the lungs.

What Fissure is Between the Right Upper and Middle Lobe?

The horizontal fissure separates the right upper and middle lobes.

It is unique to the right lung and runs horizontally, dividing these two lobes from each other.

Why Does the Left Lung Only Have Two Lobes?

The left lung has only two lobes – the superior and the inferior – primarily due to space constraints in the thoracic cavity.

The heart takes up a significant portion of the left side of the thoracic cavity, reducing the available space for the left lung and resulting in fewer lobes compared to the right lung.

How Many Fissures Does the Right Lung Have?

The right lung has two fissures: the oblique fissure and the horizontal fissure.

The oblique fissure separates the inferior lobe from the superior and middle lobes, while the horizontal fissure divides the superior lobe from the middle lobe.

Final Thoughts

Lung lobes and fissures are more than just anatomical features; they are vital to the lung’s functionality and overall respiratory health.

The distinct lobes of the right and left lungs, separated by the oblique and horizontal fissures, facilitate efficient gas exchange and adapt to the unique spatial constraints within the thoracic cavity.

Recognizing the nuances of these structures aids in the diagnosis and treatment of pulmonary conditions, underscoring their importance in the field of pulmonology and respiratory care.

Written by:

John Landry, BS, RRT

John Landry is a registered respiratory therapist from Memphis, TN, and has a bachelor's degree in kinesiology. He enjoys using evidence-based research to help others breathe easier and live a healthier life.