The bicuspid and tricuspid valves are both located between the atrium and the ventricle. They are similar in appearance and can be difficult for beginning anatomists to identify accurately. There are a couple of different ways to remember and then locate the valves. First, you must remember which valve is on the left and which valve is on the right. When a heart is “in-situ” the left and right is easy to establish, but a removed heart, the kind you will get for a dissection, the left and right side are not as easy to identify.
First, a simple mnemonic to remember that the tricuspid valve is on the right side of the heart.
TRI goes with RIGHT. If you take the “T” from the end of the word and put it at the beginning, it spells TRI.
Once you know that the tricuspid is on the right, then you would know that the bicuspid must be on the left side of the heart. The bicuspid has two other names that it goes by, also adding to confusion. It is also called the MITRAL valve and can also be accurately described as the left atrioventricular valve. Similarly, the tricuspid is also called the right atrioventricular valve.
When you open a heart, either fresh or preserved, you will need to determine which side is the left and which side is the right. The easiest way to do this on a dissected heart is to look at the wall of the ventricle. The left side of the heart is much more muscular and the wall will be thicker. This is because the left side of the heart pumps blood out of the aorta and it must have enough force to propel the blood to the entire body. During the contraction of the left ventricle (systole) the aortic valve opens and the mitral valve closes. The closing of the mitral valve prevents the regurgitation of the blood back into the atrium. Blood that has been oxygenated in the lungs travels to the left atrium, through the mitral valve, into the left ventricle, and then out the aorta (through the aortic valve.)
Lungs –> Left Atrium –> Mitral Valve –> Left Ventricle –> Aorta
The valves are held in place by the chordae tendinae which appear as strings, this is why they are sometimes referred to as the “heart strings.” These strings are anchored to strong papillary muscles.