Papillary Muscle

The papillary muscles are small muscles which anchor heart valves. These muscles contract to tighten the chordae tendineae, which in turn prevent inversion. This occurs in response to pressure gradients. Instead the papillary muscles brace the valves against the high pressure, preventing regurgitation of ventricular blood back into the atrial cavities.

The papillary muscles are projections of ventricular muscle to which the tendinous cords, or chordae tendinae, of the atrioventricular valves are attached. Contractions of the papillary muscles assist the tendinous cords in preventing the valves from being thrust out into the atrial cavity during ventricular systole.