abnormal heart valve morphology abnormal heart right atrium morphology abnormal coronary sinus valve morphology 2010-09-30T12:54:34Z MP:0010491 MPheno.ontology abnormal Thebesian valve morphology abnormal coronary valve morphology any structural anomaly of the semicircular fold of the right atrial endocardium located at the coronary sinus attachment to the right atrium that serves to prevent the reflux of blood back to the coronary arteries during atrial contraction csmith