Sometimes I think the hardest part of understanding anatomy for artists is being able to apply it to motion and action. Seeing how movement affects the appearance of the surface of the figure makes the study of anatomy so much more relevant.
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Also here is a great article on the movement of the spine. http://www.the-flying-animator.com/anatomy-for-artists.html
And if you have not already heard about it or seen it, check out the Body Worlds Exhibition