Hi I used virtual canine anatomy, also I made a table of origins and insertions etc printed out a picture of a limb stuck it in a plastic envelope and drew them on with a board marker rubbed them off then tested myself again..... Did this every time I left my uni room for 3 or so muscles. Also many of them have patterns eg the most of the distal extensors come from the lateral condyle/epicondyle and all distal forelimb extensors are innervated by the radial nerve so you only have to learn where they insert which you can work out as common digital extensor implies it's common so you can work out its the distal phalanx 2-5 (common so it must do all) . Hope this helps. Just try and spot patterns .