The fresco by Diego Rivera (1886 to 1957) on the history of cardiology was displayed at the "Instituto Nacional de Cardiología" of Mexico City at the time of inauguration on April 14, 1944. Some of the most important masters of the Padua Medical School were depicted, namely Vesalius, Harvey, and Morgagni. There is a vivid description of the anatomoclinical method introduced by Giovanni Battista Morgagni (1682 to 1771), when he was professor of Theoretical Medicine first and then of Anatomy at the University of Padua (1711 to 1771). By reading Morgagni's De sedibus, we found the case of aortic syphilitic aneurysm that corresponds perfectly with the one represented in Diego Rivera's mural. In the Museum of Pathological Anatomy of the Padua University, an anatomical specimen that displays the same lesion is preserved, and we have performed a computed tomography scan to analyze the state of the heart and aneurysm, thus finding diffuse calcific deposits of aorta and pericardium. In conclusion, in Diego Rivera's fresco the clinicopathologic method of Morgagni is well represented and the case of syphilitic aneurysm, reported by Morgagni in his De sedibus, depicted.