Paul Grilley's DVD on Yoga Anatomy is indeed a very good start. He emphasises how joints constrain the yoga practice and that all bodies are unique and therefore, there is no one good way to do a yoga posture. It depends on unique variations of one's bone anatomy. A good beginning for an indepth study of Yoga Anatomy. One must however recognize that there is a lot more happening during yoga postures esp. to muscles, glands, nerves cells, nerve fibres etc. Those aspects are not dealt with in this DVD.

Leslie Kaminoff's new book on Yoga Anatomy gives a newer look to yoga anatomy from the point of view of how breathing and respiration works. It is a useful addition to the material available on Yoga Anatomy. Recent articles by Kaomudii Yip on biomechanics of Kaoshikii and Tandava are also a useful addition to the library of Yoga Anatomy. Still, many subtler aspects of interaction between human anatomy and yoga practice need further research and we encourage all our member teachers to stay up-to-date on latest literature on the subject.

http://www.free-ed.net/free-ed/HealthCare/default.asp This may help you get started.