Very impressive app. I love love love the layering feature. Its probably the best part. Being able to isolate individual muscles is great too. Artwork is very clean and pleasing to look at as well. Muscle groups are divided well and there is an index search if you want a specific muscle.
Animations are a nice addition although sometimes the model is not articulated completely accurately. I.E. occipitals animation has the entire neck extending back at C7/T1 instead of C1/C2. If you were an absolute anatomy beginner, this might cause a little confusion, but otherwise its a very minor nitpick. This app is definitely worth the 25 bucks and I cant wait to use it to better explain muscle location/function to my clients!
Fuzzy_Blue about Anatomy In Motion - Complete - Muscle System Flashcards for iPhone and iPad, v1.0