Logan Steele
The papillary muscles are located in the ventricles of the heart and play a crucial role in cardiac function. There are five papillary muscles in total, with three in the right ventricle and two in the left ventricle. These muscles contract to prevent the inversion of atrioventricular valves during systole, maintaining proper blood flow and preventing regurgitation. The contraction of papillary muscles is regulated by cardiac plexus fibers, which innervate and control the heart's pacemaker. The morphology of these muscles can vary significantly, and abnormalities can lead to serious complications such as mitral regurgitation or even fatal rupture. Understanding the structure and function of papillary muscles is essential for surgical considerations and treating various cardiac conditions.
| Characteristics | Values |
|---|---|
| Location | Ventricles of the heart |
| Number | Five in total: three in the right ventricle and two in the left ventricle |
| Function | Prevent inversion or prolapse of the atrioventricular valves on systole |
| Contraction | Begins shortly before ventricular systole and maintains tension throughout |
| Morphology | Wide variation, including modifications in muscle morphology, ventricular wall origin, and chordae attachment |
| Blood Supply | Anterolateral muscle: left anterior descending artery and left circumflex artery; Posteromedial muscle: right coronary artery |
| Pathology | Papillary muscle rupture, dysfunction, and abnormalities have been associated with myocardial infarction, ischemia, and blunt chest trauma |
| Surgical Considerations | Papillary muscle realignment and resection have been used to treat left ventricular outflow tract obstruction caused by pathologic papillary muscle anatomy |
| Imaging | Cardiovascular magnetic resonance (CMR) and cardiac MRI are valuable imaging modalities for evaluating papillary muscle anatomy and function |
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What You'll Learn
Papillary muscle rupture
The heart contains five papillary muscles that originate from the ventricular walls. These muscles are attached to the tricuspid and mitral valve leaflets through the chordae tendineae. The papillary muscles contract to prevent inversion or prolapse of the atrioventricular valves during systole or ventricular contraction. The three papillary muscles—anterior, posterior, and septal—attach to the tricuspid valve, while the two anterolateral and posteromedial muscles connect to the mitral valve.
The anterolateral and posteromedial papillary muscles play a crucial role in maintaining mitral valve function. The anterolateral muscle has a dual blood supply, while the posteromedial muscle is supplied solely by the posterior descending coronary artery. Due to this single blood supply, the posteromedial papillary muscle is more susceptible to rupture following a myocardial infarction.
Other documented causes of papillary muscle rupture include trauma, syphilis, periarteritis nodosa, vegetative valvulitis, myocardial abscess, iatrogenic injury, and cocaine use. Rupture of the tricuspid papillary muscles can also occur due to myocardial ischemia, trauma, or infective endocarditis.
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Papillary muscle abnormalities
The papillary muscles are muscles located in the ventricles of the heart. There are five papillary muscles in the heart: three in the right ventricle and two in the left ventricle. 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). The papillary muscles of both the right and left ventricles begin to contract shortly before ventricular systole and maintain tension throughout. This prevents regurgitation, or the backward flow of ventricular blood into the atrial cavities, by bracing the atrioventricular valves against prolapse.
Papillary muscle dysfunction is another abnormality that can occur. This may be caused by ischemia, ventricular dilatation (including aneurysm), rupture of a papillary muscle, inflammatory disease of a papillary muscle, or interventricular conduction disturbances. Dysfunction can lead to mitral incompetence, regurgitation, and an apical systolic murmur. The characteristics of the murmur vary depending on the dysfunction.
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Papillary muscle development
The papillary muscles are pillar-like muscles located in the ventricles of the heart. There are five in total, with three in the right ventricle and two in the left ventricle. They attach to the cusps of the atrioventricular valves (also known as the mitral and tricuspid valves) via the chordae tendineae.
The papillary muscles contract shortly before ventricular systole and maintain tension throughout. This prevents regurgitation, or the backward flow of ventricular blood into the atrial cavities, by bracing the atrioventricular valves against prolapse. The contraction of the papillary muscles is essential for proper cardiac valvular function. Without it, the longitudinal shortening of the LV would result in a prolapse of the leaflets.
Variations in the structure of the papillary muscles can range from developmental anomalies to neoplasms. They can be asymptomatic or present with associated symptoms like outflow obstruction, and in rare cases, can lead to death. Papillary muscle rupture can be caused by a myocardial infarction, and dysfunction can be caused by ischemia. Blunt chest trauma can also, in rare cases, cause papillary muscle rupture.
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Papillary muscle morphology
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. There are five papillary muscles in the heart; three in the right ventricle and two in the left ventricle. The papillary muscles contract to prevent inversion or prolapse of the valves during ventricular contraction or systole.
The papillary muscles of both the right and left ventricles contract shortly before ventricular systole and maintain tension throughout. This action prevents regurgitation, or the backward flow of blood from the ventricles into the atrial cavities, by bracing the atrioventricular valves against prolapse. Papillary muscle rupture can be caused by myocardial infarction, ischemia, or, rarely, blunt chest trauma.
The papillary muscles can be categorised by the number of muscle heads and then sub-categorised depending on whether the heads share a common basal segment or have unique basal segments. The anterolateral (AL) muscle usually has a single major muscle group, while the posteromedial (PM) muscle contains two or three major muscle groups. When multiple muscle groups are present, they may share a common origin or have separate origins.
Papillary muscle abnormalities are common in patients with hypertrophic cardiomyopathy. These abnormalities can range from congenital anomalies to neoplasms and may be asymptomatic or associated with symptoms related to obstruction of the left ventricular outflow tract. Echocardiography is the first-line imaging modality used to evaluate cardiac abnormalities, including papillary muscles. However, cardiac magnetic resonance imaging (MRI) is also an important imaging method for papillary muscles due to its high resolution, multi-planar capabilities, and soft tissue contrast.
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Papillary muscle contraction
Papillary muscles are pillar-like muscles found in the cavity of the ventricles of the heart. They are attached to the cusps of the atrioventricular valves (also known as the mitral and tricuspid valves) via the chordae tendineae. There are five papillary muscles in the heart: three in the right ventricle and two in the left ventricle.
The papillary muscles contract to prevent inversion or prolapse of the atrioventricular valves during systole (ventricular contraction). They begin to contract shortly before ventricular systole and maintain tension throughout, preventing the backward flow of ventricular blood into the atrial cavities. The contraction of the papillary muscles is essential for proper cardiac valvular function.
The morphology of the papillary muscles can vary significantly. Abnormalities in the papillary muscles can lead to various complications, such as left ventricular outflow tract obstruction, which may require surgical intervention. One example of a surgical treatment option is papillary muscle realignment via pledget mattress stitching.
The blood supply to the papillary muscles also varies. The anterolateral papillary muscle is typically irrigated by branches of the left coronary artery, while the posteromedial papillary muscle is irrigated by the posterior descending artery, a branch of the right descending coronary artery, in most cases. However, in some instances, the posteromedial muscle receives blood supply from branches of the left circumflex artery, making it more vulnerable to ischemic episodes.
Overall, the contraction of the papillary muscles is a critical aspect of cardiac function, and their structure and blood supply are important considerations in understanding their role in maintaining proper heart valve function.
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Frequently asked questions
Papillary muscles are muscles located in the ventricles of the heart. There are five in total: three in the right ventricle and two in the left ventricle. They play an important role in normal cardiac function, helping to prevent leakage through the AV valves during systole.
Papillary muscles contract to prevent inversion or prolapse of the atrioventricular valves on systole (or ventricular contraction). This prevents regurgitation, or the backward flow of ventricular blood into the atrial cavities.
Papillary muscle dysfunction leads to regurgitation of blood through the valves, causing the backward flow of blood and potentially left- or right-sided heart failure. Papillary muscle rupture is a rare but potentially fatal complication, typically following a myocardial infarction or occurring secondary to infective endocarditis.
The papillary muscles of the left ventricle are called the anterolateral and posteromedial muscles. The papillary muscles of the right ventricle are the anterior, posterior, and septal papillary muscles.
