The sac round the heart and the layers of its wall, from the outside in.
Pericardium and Heart Wall Diagram
Name Date
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1 of 8
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Write the name of each numbered layer.Answer key
Parietal pericardium
Pericardial cavity
Visceral pericardium
Coronary blood vessel
Myocardium
Endocardium
Trabeculae carneae
Fibrous pericardium
Drawn for this site on 2026-09-29 from plain geometry. Licence: own work.
Each numbered ring is a button. Use the arrow keys to move between them and Enter to choose. Names are read out in Study, and once a layer is answered.
Parietal pericardiumThe outer layer of the serous pericardium.
Pericardial cavityIt holds a little fluid that lets the heart beat without rubbing.
Visceral pericardiumThe inner serous layer and the outer layer of the heart wall. Also called the epicardium.
Fibrous pericardiumDense connective tissue that protects the heart and anchors it.
The heart wall 4
Coronary blood vesselCoronary vessels feed the heart muscle itself.
MyocardiumCardiac muscle: the layer that contracts to pump the blood.
EndocardiumIt lines the chambers and covers the valves.
Trabeculae carneaeRidges of muscle, covered by endocardium, on the inside of the ventricles.
How this list was compiled: Every name and detail checked on 2026-09-29 against OpenStax Anatomy and Physiology 2e, section 19.1 Heart Anatomy (fibrous pericardium, serous pericardium with parietal and visceral layers, the visceral layer as the epicardium, pericardial cavity, myocardium of cardiac muscle, endocardium, coronary vessels, trabeculae carneae), https://openstax.org/books/anatomy-and-physiology-2e/pages/19-1-heart-anatomy, and against Wikipedia, Pericardium and Heart, text only. Licence: own work
The drawing: Drawn for this site on 2026-09-29 from plain geometry; nothing traced. Licence: own work
How it works
The heart sits in a double-layered sac, the pericardium, and its own wall has three layers. The first drawing cuts straight through the sac and the wall, from outside to inside; the second shows the heart in its sac.
Read the full guide
From the outside in
Numbers 1 to 3 are the serous pericardium: the thin parietal layer, the pericardial cavity and the visceral layer on the heart's surface. Number 4 is a coronary vessel in the fat. Numbers 5 to 7 are the wall: the myocardium, the endocardium and the muscle ridges inside the chamber. Number 8 is the tough fibrous sac round it all.
The visceral pericardium and the epicardium are the same layer: part of the sac and the outer layer of the heart wall.
Questions and answers
What are the layers of the pericardium?
The tough outer fibrous pericardium and the thin serous pericardium inside it. The serous pericardium has a parietal layer lining the fibrous sac and a visceral layer on the heart, with the pericardial cavity between them.
What are the three layers of the heart wall?
From outside to inside: the epicardium (the visceral pericardium), the thick muscular myocardium, and the endocardium lining the chambers.
What is in the pericardial cavity?
A thin film of fluid made by the serous layers. It lets the heart move smoothly against the sac as it beats.