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According to Walmsley,1 it was Andreas Vesalius who suggested the picturesque term “mitral” to describe the left atrioventricular valve owing to its resemblance to a plan view of the bishop’s mitre. Guarding the inlet to the left ventricle, the mitral valve prevents backflow to the left atrium during ventricular systole. In its open state, the valvar leaflets are like a funnel extending from the hinge line at the atrioventricular junction to the free margins. Tendinous cords attach the leaflets to two closely arranged groups of papillary muscles. The interchordal spaces serve as important pathways for blood flow. As emphasised by Perloff and Roberts,2 the mitral valve requires all its components, together with the adjacent atrial and ventricular musculature, in order to work properly. This review examines the component parts to provide the background for a better understanding of the mitral valve as seen in cross sectional anatomy and highlights pertinent features of its anomalies.
GENERAL ANATOMY
The valvar complex comprises the annulus, the leaflets, the tendinous cords, and the papillary muscles. Also important for its functioning is the left atrial musculature inserting to the leaflets and the myocardium to which the papillary muscles are inserted. The valve is obliquely located in the heart and has a close relation to the aortic valve (fig 1A). Unlike the tricuspid valve which is separated by muscle from its counterpart, the pulmonary valve, the mitral valve is immediately adjacent to the aortic valve (fig 1B).
(A) View of the base of the heart in anatomical orientation shows the spatial relations of the four cardiac valves. The left heart valves are close together whereas the right heart valves are separated by myocardium. Dotted line marks the limit of atrial myocardium around the mitral orifice. (B) This dissection of the heart viewed from the anterior aspect …