Learning Objective

By the end of this lesson, you should be able to describe the structure, layers, functions, innervation, and key clinical correlations of the pericardium, including cardiac tamponade and pericarditis, and understand its relationship to the great vessels.

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Overview

The pericardium is a fibroserous, fluid-filled sac that surrounds the heart and the roots of the aorta, pulmonary trunk, pulmonary veins, superior vena cava, and inferior vena cava. It is located within the middle mediastinum and plays a critical role in stabilizing and protecting the heart.

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Anatomical Structure

The pericardium consists of two major components:

Layer	Structure	Key Function	Clinical Importance
Fibrous Pericardium	Tough, dense connective tissue; continuous with the central tendon of the diaphragm	Prevents rapid overfilling of the heart	Cardiac tamponade risk due to rigidity
Serous Pericardium	Thin mesothelial layer; divided into parietal and visceral (epicardium) layers	Produces serous fluid for lubrication	Pericardial effusion may accumulate here

 

Serous Pericardium Subdivisions

• Parietal layer – lines the inner surface of the fibrous pericardium
• Visceral layer (Epicardium) – adheres directly to the heart surface
• Pericardial cavity – contains lubricating serous fluid

Mnemonic (Non-clinical aid): “Fart Police Smell Villains.”

• F – Fibrous
• P – Parietal
• S – Serous fluid
• V – Visceral

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Functions of the Pericardium

• Fixation – Anchors the heart to the diaphragm, sternum, and great vessels
• Prevents overfilling – Inextensible fibrous layer limits acute dilation
• Lubrication – Serous fluid reduces friction during cardiac contraction
• Protection – Physical barrier against the spread of infection from adjacent organs (e.g., lungs)

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Activity

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Pericardial Sinuses

Transverse Pericardial Sinus

Located:

• Posterior to the ascending aorta and the pulmonary trunk
• Anterior to superior vena cava

Clinical Importance: Used in coronary artery bypass grafting (CABG) to clamp the aorta and pulmonary trunk.

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Innervation

The pericardium receives somatic sensory innervation from the phrenic nerves (C3–C5).

• The same nerves innervate the diaphragm
• Referred shoulder pain occurs in pericardial irritation

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Activity

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Clinical Correlations

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Cardiac Tamponade

Accumulation of fluid (pericardial effusion) within the pericardial cavity compresses the heart.

• Rigid fibrous pericardium prevents expansion
• Reduced cardiac output
• Medical emergency

Pericarditis

Inflammation of the pericardium, commonly due to:

• Viral or bacterial infection
• Post-myocardial infarction

May lead to:

• Chest pain
• Pericardial effusion
• Acute tamponade

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Activity

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Activity