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Posterior papillary muscle

The posterior papillary muscles are muscular projections of the ventricular myocardium that attach to the atrioventricular valves through chordae tendineae. Both the right ventricle (RV) and the left ventricle (LV) contain a posterior papillary muscle, each essential for valve stability and function.

  • In the right ventricle, the posterior papillary muscle arises from the inferior ventricular wall and sends chordae tendineae to the posterior and septal cusps of the tricuspid valve. It is typically smaller and less prominent than the anterior papillary muscle.

  • In the left ventricle, the posterior papillary muscle arises from the posteromedial wall and attaches via chordae tendineae to the anterior and posterior leaflets of the mitral valve. Unlike the anterior papillary muscle (anterolateral), the posterior papillary muscle has a more variable blood supply, making it more vulnerable to ischemia and infarction, particularly from right coronary artery or left circumflex artery occlusion.

Papillary muscle dysfunction due to ischemia, rupture, fibrosis, or congenital anomalies can lead to tricuspid regurgitation (RV) or mitral regurgitation (LV), contributing to heart failure and hemodynamic instability. Posterior papillary muscle rupture is a well-recognized, life-threatening complication of acute myocardial infarction.

Synonyms

  • Right ventricular posterior papillary muscle (tricuspid valve)

  • Left ventricular posterior papillary muscle (posteromedial papillary muscle of mitral valve)

  • Papillaris posterior

Function

  • Right posterior papillary muscle (RV): stabilizes posterior and septal cusps of the tricuspid valve

  • Left posterior papillary muscle (LV): stabilizes both mitral leaflets (anterior and posterior)

  • Prevents valve prolapse into the atria during systole

  • Ensures unidirectional flow of blood (RA → RV → pulmonary trunk; LA → LV → aorta)

  • Coordinates with anterior papillary muscles to maintain valve competence

MRI Appearance

T1-weighted images:

  • Appear as intermediate signal myocardial structures similar to surrounding ventricular myocardium

  • Surrounded by blood pool, which shows signal void

T2-weighted images:

  • Normally intermediate to low signal

  • Edema, ischemia, or infarction in papillary muscles appears as hyperintense signal

STIR (Short Tau Inversion Recovery):

  • Suppresses fat, highlighting edema and inflammation

  • Papillary muscle injury appears hyperintense

T1 Post-Contrast (Gadolinium-enhanced):

  • Normal papillary muscles enhance homogeneously like myocardium

  • Late gadolinium enhancement (LGE) indicates infarction, fibrosis, or scarring, often localized to the posterior papillary muscle in inferior MI

MRI Non-Contrast Cardiac-Gated 3D Coronary Imaging:

  • Posterior papillary muscles visualized as well-defined muscular projections into ventricular cavities

  • Useful for detecting hypertrophy, displacement, or post-infarct damage

CT Appearance

CT Coronary Angiography (CCTA):

  • Posterior papillary muscles appear as soft tissue density structures projecting into the ventricular lumen

  • Provides detailed evaluation of morphology, hypertrophy, rupture, or ischemic complications

  • Excellent for preoperative assessment in valve disease, ischemic cardiomyopathy, and congenital anomalies

CT image left

Posterior papillary muscle of left ventricle anatomy CT axial image -img-00000-00000

CT image right

Posterior papillary muscle of rt ventricle anatomy CT axial image -img-00000-00000

MRI image

Posterior papillary muscle mri image