abnormal heart valve morphology abnormal heart right atrium morphology abnormal coronary sinus valve morphology csmith abnormal Thebesian valve morphology MP:0010491 2010-09-30T12:54:34Z abnormal coronary valve morphology MPheno.ontology 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