The mitral orifice.
D000790:Angiocardiography; D002815:Chordae Tendineae / Q000473:pathology; D005260:Female; D006325:Heart Atria; D006352:Heart Ventricles; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000473:pathology*; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging; D008946:Mitral Valve Stenosis / Q000000981:diagnostic imaging