any structural anomaly of the spaces betwen the superior aspect of each of the three cusps of the aortic valve and the dilated portion of the wall of the ascending aorta, immediately above each cusp; the three sinuses include the posterior (non-coronary sinus), and the right and left aortic sinuses (from which the left and right coronary arteries arise) (Mammalian Phenotype Ontology, MP_0010482)
