I did some research on Muscle wing anatomy for my Science Illustration class at UCSC back in 2007. I looked into some work done by John Sibbick (a master on dinos and pterosaurs), and compared the pterosaur wing and flexibility in flight to the wing of Bats. I used something that looked more like a bat than a pterosaur. Inspired by the works of Todd Lockwood and Terryl Whitlatch, look them up if you haven't already.