What is the Difference Between Parietal and Visceral Pleura

The key difference between parietal and visceral pleura is that parietal pleura is the outer layer of the pleural membrane, while visceral pleura is the inner layer of the pleural membrane.

The pleural membrane is the thin, moist, slippery membrane that has two layers: parietal and visceral pleura. Between the two layers of the pleural membrane, there is an intrapleural space, which normally contains fluid secreted by membranes. Pleural membrane helps to reduce the friction between the lungs and inside the chest wall during breathing. It also allows optimal expansion and contraction of the lungs during breathing.

CONTENTS

1. Overview and Key Difference
2. What is Parietal Pleura
3. What is Visceral Pleura
4. Similarities – Parietal and Visceral Pleura
5. Parietal vs Visceral Pleura in Tabular Form
6. Summary – Parietal vs Visceral Pleura

What is Parietal Pleura?

Parietal pleura is the outer layer of pleural membrane. Normally, the parietal pleura is attached to the chest wall. It also lines the inner surfaces of the thoracic cavity on each side of the mediastinum. The parietal pleura is set apart from the thoracic wall by the endothoracic fascia. The parietal pleura is further subdivided into mediastinal, diaphragmatic, costal, and cervical pleurae.

The mediastinal pleura covers the side surfaces of the fibrous pericardium, oesophagus, and thoracic aorta. The diaphragmatic pleura is the portion that covers the convex upper surface of the diaphragm. Its junction with the costal pleura at the diaphragmatic margin in a sharp gutter. This sharp gutter is known as costodiaphragmatic recess. Costodiaphragmatic recess has diagnostic significance on plan radiography. The costal pleura is the pleural portion that covers the inside of the rib cage. It is separated from the ribs/cartilages and intercostal muscles through endothroracic fascia. Moreover, the cervical pleura covers the underside of the suprapleural membrane. The cervical pleura bulges beyond the thoracic inlet into the posterior triangle of the neck. This is the most vulnerable part of the pleura and can be punctured by subclavian catheterization or a neck injury.

What is Visceral Pleura?

Visceral pleura is the inner layer of the pleural membrane. It covers the lungs, blood vessels, nerves, and bronchi. It extends caudally from the hilum as a mesentery-like band called the pulmonary ligament. The function of the visceral pleura is to produce and reabsorb fluid. It is also an area pleural membrane that is insensitive to pain due to association with the lung and innervations by visceral sensory neurons.

The visceral pleura is a thin and slippery membrane. It dips into areas separating the different lobes of the lungs called hilum. Each lung is divided into lobes through the infolding of the pleura as fissures. The fissures are double folds of pleura that help the lungs in their expansion, allowing the lung to ventilate more effectively.

What are the Similarities Between Parietal and Visceral Pleura?

• The parietal and visceral pleura are the two layers of the pleural membrane.
• Both layers help to reduce the friction between the lungs and inside the chest wall during breathing.
• These layers are involved in making a pleural cavity.
• Both layers involve in making pleural fluid and reabsorbing it.

What is the Difference Between Parietal and Visceral Pleura?

The parietal pleura is the outer layer of the pleural membrane, while the visceral pleura is the inner layer of the pleural membrane. Thus, this is the key difference between parietal and visceral pleura. Moreover, the parietal pleura lines the inner surfaces of the thoracic cavity on each side of the mediastinum, while the visceral pleura lines the lungs, blood vessels, nerves, and bronchi.

The below infographic presents the differences between parietal and visceral pleura in tabular form for side by side comparison.

Summary – Parietal vs Visceral Pleura

The parietal and visceral pleura are the two layers of the pleural membrane. Of these, the parietal pleura is the outer layer of the pleural membrane, while the visceral pleura is the inner layer of the pleural membrane. So, this is the key difference between parietal and visceral pleura.

Reference:

1. “Visceral Pleura.” An Overview | ScienceDirect Topics.
2. “Parietal Pleura.” An Overview | ScienceDirect Topics.

Image Courtesy:

1. “Figure 39 03 04” By CNX OpenStax – (CC BY 4.0) via Commons Wikimedia
2. “2313 The Lung Pleurea” By OpenStax College – Anatomy & Physiology, Connexions Web site. Jun 19, 2013. (CC BY 3.0) via Commons Wikimedia

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