Well I was thinking about it, and both the wings and the shoulder joint connect to the collar bone and the shoulderblade, right?
Meaning that when they fly it’d have to do something like this
Either dislocating the collarbone on the upwards flap, or dislocating the shoulder on the downflap.
The farthest back the wing would be able to pull without dislocating the shoulder is about this far.
But wait… what if the wings aren’t even supposed to be there?
So a bird’s center of gravity is here.
Right between their wings. A human’s on the other hand, is here.
A human’s is right here, between the first to third vertebrae. However, a bird’s wings need to be over the center of gravity. Meaning that instead of being up near the shoulders, an anatomically correct angel’s wings would be closer to here.
So, due to shoulder dislocations and centers of gravity.