Heart valve tricuspid valve has anterior, posterior, and septal cusps; and the mitral valve has just anterior and posterior cusps. The valves of the human heart can be grouped in two sets: 1- Two Atrioventricular (AV) valves to prevent backflow of blood from the ventricles into the atria a) Tricuspid valve, located between the right atrium and right ventricle. b) Bicuspid or mitral valve, located between the left atrium and left ventricle. 2- Two Semilunar valves to prevent the backflow of blood into the ventricle a) Pulmonary semilunar valve, located at the opening between the right ventricle and the pulmonary trunk. b)
Mitral valve prolapse "atrialis", "fibrosa", and "spongiosa". Patients with classic mitral valve prolapse have excess connective tissue that thickens the spongiosa and separates collagen bundles in the fibrosa. This is due to an excess of dermatan sulfate, a glycosaminoglycan. This weakens the leaflets and adjacent tissue, resulting in increased leaflet area and elongation of the chordae tendineae. Elongation of the chordae tendineae often causes rupture, commonly to the chordae attached to the posterior leaflet. Advanced lesions—also commonly involving the posterior leaflet—lead to leaflet folding, inversion, and displacement toward the left atrium. Echocardiography is the most useful method of diagnosing a prolapsed mitral valve.