This magnificent drawing is a summary of Leonardo’s researches into the internal organs, following his dissection of the old man in 1507 – 8. Many of the structures are transcribed directly from drawings in the notebook compiled at that time (though the prominent ligaments extending from the sides of the uterus are derived from the dissection of a cow). Leonardo used a range of illustrative conventions – the vessels overlap each other, the heart is sectioned through, the uterus is transparent, and the whole system is seen within the external outlines of the body.