The right ventricle and tricuspid valve

The drawing at the centre of this sheet shows the right ventricle of the heart sectioned to reveal the papillary muscles within, their chordae tendineae (the ‘heart strings’) reaching up to the tricuspid valve. At centre right are two views, from either side, of the valve when closed. The diagram at the top of the sheet shows the heart cut through above and below the valve to give a rough cylinder, and then cut longitudinally and opened out. The three cusps of the valve are seen lying flat against the heart wall, with the papillary muscles along the lower margin and their chordae fanning out to the cusps. Leonardo’s last known anatomical campaign, an analysis of the heart, was perhaps the most brilliant of his many scientific investigations. His dissections were of an ox’s heart, focussing on the action of the valves in a series of densely annotated sheets. It would be many years before any other anatomist approached his understanding of the heart’s operation. Text adapted from Leonardo da Vinci: A life in drawing, London, 2018