Bandha Yoga: Scientific Keys to Unlock the Practice of Hatha Yoga has fantastic illustration of the skeletal and muscular framework for doing yoga. The book is expensive at $48, but its unique perspective makes it different than any yoga book that I have seen so far. There is a 32 page sample chapter that you can examine to see if you want to bite.
Ray Long MD is a board certified orthopedic surgeon and the founder of Bandha Yoga. Long studied at The University of Michigan Medical School with post-graduate training at Cornell University, McGill University, The University of Montreal and Florida Orthopedic Institute. He has studied hatha yoga for over 20 years, training extensively with B.K.S. Iyengar, among others.
The illustrator is Chris Macivor, a graduate of Etobicoke School of The Arts, Sheridan College and Seneca College.