Interesting link, especially since I teach anatomy and use several of Leonardo's drawings in my introductory lecture. Several I use show the meticulous detail due to his amazing ability to observe. One I use is just plain wrong -
Leonardo never dissected a penis (I get the jitters just thinking about placing scalpel to shaft and slicing

) and therefore gets the anatomy all wrong. It was inconceivable at the time that urine and semen passed through the same duct - there must be two. And so he illustrated it that way.
Regardless, many (most, dare I say) of his anatomical drawings are both accurate and beautiful.
Enough anatomy, I'm on break, away foa while until I start teaching again in July.