The fibrous sac covering the heart is called the pericardium.

Appeared in: MP CHO - 2022

Explanation

The pericardium is the fibro-serous sac that encloses the heart, providing protection and support.
It is composed of an outer, tough fibrous layer and an inner, double-layered serous membrane (parietal and visceral).
The primary functions of the pericardium are to protect the heart, anchor it within the chest cavity, and prevent it from overfilling with blood.
The space between the serous layers, the pericardial cavity, contains a small amount of fluid (15-50 mL) that lubricates the heart's movements.

Option A: The endocardium is the innermost layer of the heart, lining the chambers and valves. It is not the outer sac.
Option B: The myocardium is the middle, muscular layer of the heart responsible for its pumping action. It is the heart muscle itself, not the sac covering it.
Option C: The epicardium is the outermost layer of the heart wall itself. While it is also the visceral layer of the serous pericardium, it is only one part of the entire pericardial sac and not the complete fibrous covering.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Anatomy of the heart layers and pericardium as background academic context rather than a clinical decision trigger.
Understanding the heart's layers is fundamental for nurses to recognize and manage conditions like endocarditis (infection of the inner lining), myocarditis (inflammation of the heart muscle), and pericarditis (inflammation of the outer sac).
A key assessment finding for pericarditis is a pericardial friction rub, a scratching sound heard on auscultation, caused by the inflamed layers rubbing against each other.
A rapid accumulation of fluid in the pericardial space (cardiac tamponade) is a medical emergency. Nurses must recognize Beck's triad (low blood pressure, jugular vein distention, muffled heart sounds) and act swiftly.

How to Approach the Question

First, identify the keywords in the question stem: "fibrous sac" and "covering the heart".
Recognize this as a direct factual recall question about cardiac anatomy.
Analyze the prefix "peri-" which means "around" or "surrounding," providing a strong clue that pericardium is the correct term for something that covers the heart.
Systematically review the definitions of each option: Endocardium (inner), Myocardium (muscle), Epicardium (outer layer of heart wall), and Pericardium (sac surrounding the heart).
Match the definition from the question, "fibrous sac covering the heart," with the correct anatomical term, which is Pericardium.

Concept Tested & Keywords

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E6 Anatomy Applied Ashalatha 4e p. 167-169

E6 Medicine Harrison 22e Part 1 p. 2119-2121

Practise the full MP CHO - 2022

Attempt every question from this paper in a timed mock, then review the full solution for each one.