Previous episode: here.
Leonardo da Vinci's Vitruvian Man is anatomically impossible. He has drawn a man whose legs rotate around his navel (light blue dot in the image below), which is physically impossible. In fact, each leg rotates around the corresponding hip joint (green dot below for the left leg). The green dashed arc shows how the big toe would really move if the leg swung sideways. To be consistent with the drawing, the man's legs must shrink when moved sideways!
For comparison, consider the Vitruvius interpretation by Claude Perrault (Les Dix Livres d’architecture de Vitruve, corrigez et traduits nouvellement en françois avec des notes et des figures, edition 1684, Book III, Plate VII).
Superimposing the separate figures, we obtain this:
Perrault's circle man does not point his toes forward, and so there is no possibility to check if his leg has shrunk, like with da Vinci. Anyhow, there is no evident impossibility.
*
