The basics of the human muscle anatomy (muscle innervation, insertion/origin, action) is critical when studying for any physical therapy and specifically critical when studying for the OCS exam. It can be very difficult and challenging as most anatomy texts do not provide quick summaries at a quick glance. I take no credit for the anatomy documents posted on these sites. I found these charts and graphs via Dr. Christiane Riedinger personal website www.dr-cee.net. She has a tremendous amount of information that she has posted as she went through her medical studies. Much of her information is outside the scope of studying for the OCS exam, nevertheless, it is a great medical resource for a variety of topics.