The tricuspid valve
is located between the right atrium
and right ventricle
in the heart. It ensures that blood doesn't flow back from the ventricle into the atrium.
When the atrium contracts, the valve opens, and blood is pumped from the right atrium into the right ventricle. When the ventricle contracts, the valve closes, thus preventing blood from returning to the atrium.
The valve has three flaps (hence - tricuspid) that are attached to the papillary muscle (the heart's walls) by chordae tendineae.
Ailments of the tricuspid valve include Tricuspid Regurgitation, in which there is not enough opposition by the valve, and blood flows backwards into the right atrium, and Tricuspid Stenosis, in which there is a narrowing at the tricuspid orifice obstructing flow from the right atrium to the right ventricle.