I know; I think I mentioned that in the original post. But seriously, I took the photo onlyl a few minutes after I'd heard the bang as it hit the window and got the bird to have a look and check its condition.
It surprised me too: the bones are so obvious, aren't they? I didn't realise that was how they looked at that part of the wing... at least, in thrushes, anyway. I wonder if most/all birds look like that on the inner wing? No... I think from the pictures I've seen of birds of prey etc that usually there are more feathers there. Perhaps it's to do with the type of bird, and the type of wing. Maybe it's like that for most songbirds or something? o_O