Papillary muscle

Papillary muscles are projections of mural cardiac muscle that are located in the chambers of the heart near the cuspid valves. The muscles are connected to the leaflets of the atrioventricular valves (mitral and tricuspid) by means of tendons (chordae tendineae). The papillary muscles contract simultaneously with the contraction of the ventricular musculature, stretching and pulling the valve leaflets into the ventricles. This prevents unwanted arching of the valves towards the atria and possible regurgitation of blood from the ventricles into the atria during ventricular systole. Papillary muscle contraction does not affect valve opening and closing - heart valves open and close based on a pressure gradient.