Bicuspid heart valve, gross clinical specimen. These are the chordae tendineae, string-like processes that attach the outer parts of the bicuspid or mitral valve to the ventricle. The valve controls the flow of blood from the heart's left upper to lower chamber (atrium to ventricle). The valve consists of two flaps (cusps), which function to allow a one-way flow of blood. Rupture of the chordae, through injury, may cause failure of the valve to close allowing a reverse flow of blood (mitral incompetence). Defects of the valve include the narrowing of the valve (stenosis) due to scarring following rheumatic fever.