Just a brief response -- despite the host's claim to "ruin everything" by giving counterfactual stories, he's actually delivering a very mainstream hagiography of Vesalius that would have not seemed out of place in the 19th century (though still is popular today, especially in the medical field). The actual history -- both of Vesalius' accomplishments, the long-running influence of Galen, and the birth of scientific medicine -- is much more nuanced.

So just briefly -- human dissection was picked up again by Europeans in the 13th century in Italy, influenced by Arab medicine. When the host talks about "Galen" he's talking about Arab text books translated into Latin like "The Canon of Medicine." By Vesalius' time (16th century), Galen would have also been translated directly from the original Greek into Latin, but Arabic translations were still a large part of the curriculum (and remained that way in some areas into the 19th century). Arab physicians were greatly influenced by Galen, but more recent scholars have shown that there was also a great deal of innovation in this period as well. Al-Nafis, for example, largely described the pulmonary circulation based on dissection, and had already corrected some of Galen's misconceptions, including that the septum of the heart was fully porous.

Mondino is probably one of the first European Arab-inspired physicians, and who most inspired Vesalius. His "Anatomy" was basically a dissection guide (the spiritual predecessor to the disgusting formaldehyde-covered guide that I used and ruined in my first year of medical school). It was based on his observations rather than old text books, though was not illustrated (since it was a guide). Vesalius used his book when doing his dissections.

So here's the biggest misconception that the video probably advocates -- while we see Vesalius as the father of anatomy, he most certainly did not see himself in that way. Galenic medicine (or what we should probably call something like "traditional Western medicine," though "humoral theory" is usually used) is an all-encompassing explanatory model. Anatomy and physiology are not seen as separate disciplines. Vesalius clearly thought of himself as participating in this tradition, and thought that his findings would help shore up this model by improving on Galen -- and then, most importantly, disseminating this information.

The hagiography about the challenge to Galen is a creating of 18th century doctors who wanted an origin story (and one that would conveniently create a link between the Greeks and European physicians and cleverly cut out the Arabs).

So that was a bit longer than I intended. The history of science and medicine is fascinating, and I think helps us understand trends today. BUT repeating simplified stories like the one in the video do little to help us understand how scientists and doctors think, or the complicated, messy tale of scientific advance. I'll get off my soap box now.