According to Reuters, at the site, without a link, two Brazilian doctors have found anatomical lessons in 34 of the 38 panels of the Sistine Chapel.
God and his angels, in the creation of Adam, is part of the brain.
God’s purple robe is a lung from a side view and the tree is a bronchial tube, in the creation of Eve, breathing life into her.
The two have published a book in Brazil and are looking at publishing in English. The article notes:
“Indeed, why would Michelangelo hide drawings of human organs in the Sistine Chapel?
Barreto and Oliveira say they aren’t sure, but it is well known that Michelangelo and other Renaissance artists were obsessed with human anatomy and the human body. There are also other examples of artists “hiding” objects in their paintings, images that can only be seen from a certain perspective.”
I don’t understand why the hiding wouldn’t be understood. It was my understanding, perhaps I am wrong, that the church specifically forbid the cutting of cadavers. Many scientists stole cadavers or bought them off of thieves. If Michelangelo wasn’t supposed to know this stuff, but he wanted a teaching tool which wasn’t stolen, this seems to me to be a perfect idea.