In which order to the various layers of the heart go?

From outside to inside, the layers are:

• Parietal pericardium
• Pericardial cavity
• Visceral pericardium (also known as the epicardium)
• Myocardium
• Endocardium

Actually, this question can almost be worked out in its entirety by knowing a (very!) little of the Classical Greek and Latin from which the terms are derived.

• Cardium is latinised form of the Greek 'kardion', meaning heart.


• Peri- refers to 'around'. Thus, the layer around (i.e. outside) the heart would be the pericardium.


• Myo- denotes muscle, also from the Greek root. Thus, the heart muscle is the myocardium.


• Endo- comes from the Greek word for 'within'. In other words, the layer on the inside of the heart is the endocardium.


• Lastly, there's the issue of 'parietal' vs 'visceral'. This is a little more obscure, but 'visceral' refers to the inner organs of the chest and abdomen, whereas 'parietal' refers to a wall. Thus, the visceral pericardium hugs the heart (one of the viscera), whereas the parietal pericardium is nearer to the walls of the chest cavity, and is even fused to one of them - the diaphragm.

This may all seem a little silly, but knowing a few choice prefixes and suffixes (as opposed to studying the original languages, which would be crazy) really makes learning biology and medicine a lot easier.