Papillary muscle

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.

[3] The papillary muscles of both the right and left ventricles begin to contract shortly before ventricular systole and maintain tension throughout.

[1] 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.

Rarely, blunt chest trauma can be the cause of papillary muscle rupture, resulting from the sudden deceleration or compression of the heart.