Now add in the ridge of the back, slightly arched upward, as well as the wing's skeleton. Remember that a basic and more realistic dragon, usually has 4 "fingers", in this picture, the dragon is quite relaxed, so I made his wings slightly folded down. Keep in mind that the "arm" of the wing, is called that for a very clear reason, it resembles a human arm. Don't make the arm too thick, or too thin if you are going for a realistic look.