Papillary muscle
Template:Short description Template:Use dmy dates Template:Infobox muscle
The papillary muscles are muscles located in the ventricles of the heart. They attach to the cusps of the atrioventricular valves (also known as the mitral and tricuspid valves) via the chordae tendineae and contract to prevent inversion or prolapse of these valves on systole (or ventricular contraction).<ref name=moore>Template:Cite book</ref>
Structure
There are five total papillary muscles in the heart; three in the right ventricle and two in the left ventricle. The anterior, posterior, and septal papillary muscles of the right ventricle each attach via chordae tendineae to the tricuspid valve. The anterolateral and posteromedial papillary muscles of the left ventricle attach via chordae tendineae to the mitral valve.<ref>Netter's Atlas of Human Anatomy, plates 216B and 217A</ref>
Blood supply to the left ventricle
The mitral valve papillary muscles in the left ventricle are called the anterolateral and posteromedial muscles.<ref name="2011 rupture article">Template:Cite journal</ref>
- Anterolateral muscle blood supply: left anterior descending artery - diagonal branch (LAD) and left circumflex artery - obtuse marginal branch (LCX)
- Posteromedial muscle blood supply: right coronary artery - posterior interventricular artery (RCA)
The posteromedial muscle ruptures more frequently because it only has one source of blood supply, hence RCA occlusion can cause papillary muscle rupture.<ref name="2011 rupture article" />
Function
The papillary muscles of both the right and left ventricles begin to contract shortly before ventricular systole and maintain tension throughout.<ref name=moore /> This prevents regurgitation—backward flow of ventricular blood into the atrial cavities—by bracing the atrioventricular valves against prolapse—being forced back into the atria by the high pressure in the ventricles.<ref name=moore />
Clinical significance
Papillary muscle rupture can be caused by a myocardial infarction, and dysfunction can be caused by ischemia. Rarely, blunt chest trauma can be the cause of papillary muscle rupture, resulting from the sudden deceleration or compression of the heart.<ref>Template:Cite journal</ref> Complications may lead to worsening of mitral regurgitation.<ref name=agabegi2nd-p40>Template:Cite book</ref>
Additional images
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Opened chambers of the heart displaying papillary muscles and chordae tendineae
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Papillary muscle infarction
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Papillary muscles and chordae tendineae
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Papillary muscles and chordae tendineae
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Papillary muscles. Deep dissection.
See also
References
External links
- Template:SUNYAnatomyLabs} — "Heart: The Right Atrioventricular (Tricupsid) Valve" (anterior, posterior, septal papillary muscles)
- Template:SUNYAnatomyLabs — "Heart: The Left Atrioventricular (Mitral) Valve" (anterior, posterior papillary muscles)
- Template:UMichAtlas} — "Right atrioventricular bundle branch, anterior view"
- Definition of Papillary muscle
- MedicineNet Search Results