They took x-rays and were very sweet to him and, although they couldn't explain much in English, I did understand that his elbow was twisted and partially dislocated. They did a twist and pop thing and Johnny screamed bloody murder, but he was fine by the time we left and was playing with it all afternoon at home.
At our follow-up with the American doctor he explained it more. With all my learning and reading I've never come across "Nursemaid's Elbow". It's apparently very common. I'm glad it was nothing too serious, but he said that it's likely to reoccur after it happens once and showed us how to slip it back into place (eep!). Needless to say, we'll be very careful with Johnny's little elbows! Today he's crawling on it as if nothing happened :)