The best book that I have seen on the subject is “Clemente- Anatomy” it is actually a medical reference.
But as far as movement science goes you will need to get a book aimed at phsyiotherapists or sports scientests, cant think of the names of the books off the top of my head. I think one is ‘Joint Structure and Function’
You really need to know which muscle contraction cause which joint to bend. It is also really important to understand the attachment points and how the muscle lever off of the bones.
Then you also need to learn the language of anatomy and movement science to understand these books.
I was lucky enough to work with a team of physiotherapists for over two years while we worked on Torson the virtual athlete.
But as frunmpy mentioned the Fine Art site, has some excellent reference.