So I've been "copying" or using the "Drawing anatomy with the masters" as a reference to just practice and get a better grip on anatomy. See my sketchbook to see the results.
Anyway, I notice some parts of their anatomy are a bit odd. Like their "cauliflower" knees. I've never seen knees like that for real. Nor do the anatomical references in the back of the book support this kind of knee.
So where do they come from?