(A) Top (atrial) view of the mitral valve in the closed (left) and open (right) position. (B) Bottom (ventricular) view of the mitral valve, cut open at the commissures to display the posterior (left) and anterior (right) leaflets. Dotted white line demarcates leaflet center from free edge. Chordae may have basal or marginal insertion into leaflet. Scale bar = 1cm. Reprinted from Grande-Allen KJ, Calabro A, Gupta V, Wight TN, Hascall VC, Vesely I. Glycosaminoglycans and proteoglycans in normal mitral valve leaflets and chordae: association with regions of tensile and compressive loading. Glycobiology. 2004;14(7):621–33 with permission from Oxford Journals.