The wing is actually the fourth finger of the pterosaur (it seems there is some disagreement about that, but most palaeontologists believe the four phalanges of the fourth finger make the wing.) The pteroid, to me, looks like a thumb, but the scientists say it is not. Well, since I have no more foam, I decided to at least draw the plans for the rest of the pterosaur.
This is the first phalanx and the hand.
And these are the last three phalanges.
And this is a much better estimate of the wingspan: