The tricuspid valve, or right atrioventricular valve, is on the right dorsal side of the mammalian

heart The heart is a muscular organ found in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon diox ...

, at the superior portion of the

right ventricle A ventricle is one of two large chambers toward the bottom of the heart that collect and expel blood towards the peripheral beds within the body and lungs. The blood pumped by a ventricle is supplied by an atrium, an adjacent chamber in the upper ...

. The function of the valve is to allow

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in th ...

to flow from the

right atrium The atrium ( la, ātrium, , entry hall) is one of two upper chambers in the heart that receives blood from the circulatory system. The blood in the atria is pumped into the heart ventricles through the atrioventricular valves. There are two a ...

to the right ventricle during diastole, and to close to prevent backflow ( regurgitation) from the right ventricle into the

during right ventricular contraction (

systole Systole ( ) is the part of the cardiac cycle during which some chambers of the heart contract after refilling with blood. The term originates, via New Latin, from Ancient Greek (''sustolē''), from (''sustéllein'' 'to contract'; from ' ...

Structure

The tricuspid valve usually has three cusps or leaflets, named the anterior, posterior, and septal cusps. Each leaflet is connected via

chordae tendineae The chordae tendineae (tendinous cords), colloquially known as the heart strings, are inelastic cords of fibrous connective tissue that connect the papillary muscles to the tricuspid valve and the mitral valve in the heart. Structure The chord ...

to the anterior, posterior, and septal papillary muscles of the

, respectively. Tricuspid valves may also occur with two or four leaflets; the number may change over a lifetime.

Function

The tricuspid valve functions as a one-way valve that closes during ventricular systole to prevent regurgitation of blood from the right ventricle back into the right atrium. It opens during ventricular diastole, allowing blood to flow from the right atrium into the right ventricle. The back flow of blood is also known as regression or tricuspid regurgitation. Tricuspid regurgitation can result in increased ventricular preload because the blood refluxed back into the atrium is added to the volume of blood that must be pumped back into the ventricle during the next cycle of ventricular diastole. Increased right ventricular preload over a prolonged period of time may lead to right

ventricular enlargement Cardiomegaly (sometimes megacardia or megalocardia) is a medical condition in which the heart is enlarged. As such, it is more commonly referred to simply as "having an enlarged heart". It is usually the result of underlying conditions that make t ...

(dilatation), which can progress to right heart failure if left uncorrected.

Clinical significance

Infected valves can result in

endocarditis Endocarditis is an inflammation of the inner layer of the heart, the endocardium. It usually involves the heart valves. Other structures that may be involved include the interventricular septum, the chordae tendineae, the mural endocardium, or the ...

in intravenous drug users. Patients who inject narcotics or other drugs intravenously may introduce infection, which can travel to the right side of the heart, most often caused by the

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were am ...

'' S. aureus''. In patients without a history of intravenous exposure, endocarditis is more frequently left-sided. The tricuspid valve can be affected by

rheumatic fever Rheumatic fever (RF) is an inflammation#Disorders, inflammatory disease that can involve the heart, joints, skin, and brain. The disease typically develops two to four weeks after a Streptococcal pharyngitis, streptococcal throat infection. Sign ...

, which can cause tricuspid stenosis or tricuspid regurgitation. Some individuals are born with

congenital A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities c ...

abnormalities of the tricuspid valve. Congenital apical displacement of the tricuspid valve is called Ebstein's anomaly and typically causes significant tricuspid regurgitation. Certain carcinoid syndromes can affect the tricuspid valve by producing fibrosis due to serotonin production by those tumors. The first endovascular tricuspid valve implant was performed by surgeons at the

Cleveland Clinic Cleveland Clinic is a nonprofit American academic medical center based in Cleveland, Ohio. Owned and operated by the Cleveland Clinic Foundation, an Ohio nonprofit corporation established in 1921, it runs a 170-acre (69 ha) campus in Cleveland, ...

Tricuspid regurgitation

Tricuspid regurgitation is common and is estimated to occur in 65–85% of the population. In the Framingham Heart Study presence of any severity of tricuspid regurgitation, ranging from trace to above moderate was in 82% of men and in 85.7% of women. Mild tricuspid regurgitation tends to be common, benign, and in structurally normal tricuspid valve apparatus can be considered a normal variant. Moderate or severe tricuspid regurgitation is usually associated with tricuspid valve leaflet abnormalities and/or possibly annular dilation and is usually pathologic which can lead to irreversible damage of

cardiac muscle Cardiac muscle (also called heart muscle, myocardium, cardiomyocytes and cardiac myocytes) is one of three types of vertebrate muscle tissues, with the other two being skeletal muscle and smooth muscle. It is an involuntary, striated muscle tha ...

and worse outcomes due to chronic prolonged right ventricular volume overload.

Additional images

File:Slide14bek.JPG, Tricuspid valve. Deep dissection. File:Tricuspid valve * Válvula tricúspide.svg, Tricuspid valve marked in yellow. File:MitralInsufficiency.jpg, Diagram of tricuspid insufficiency/regurgitation. Marked in black arrow.

References

External links

* * Photo of model
circulation/tricuspidvalve04
at Waynesburg College
Cardiac Valve Animations - Perioperative Interactive Education Group
{{DEFAULTSORT:Tricuspid Valve Cardiac anatomy Heart valves