A drawing created by Leonardo de Vinci circa 1490. It is accompanied by notes above and below the image, in Leonardo's mirror writing. His image is based on the work of the ancient Roman architect Vitruvius, representing supposedly ideal human proportions — it's also called the Canon of Proportions. In pen and ink on paper, it is stored in the Gallerie dell'Accademia in Venice.
As Maria Popova remarked recently, Leonardo's drawing has been regarded as the quintessential symbol of Renaissance breadth of knowledge and accomplishment.
Leonardo's image, of course, reflects a long cultural history of anthropormorphism and gender bias. Alternative perspectives have grown, as illustrated by this logo of the Science and Environmental Health Network: