Well, the "funny bone" isn't a bone, at all. When you hit your elbow in a way that the blow compresses your ulnar nerve, that's what hurts. That's the funny bone.
@PhoenixPhail Thank you for that explanation. I think the name "funny bone" itself comes from the fact that even though it hurts like the dickens, for some reason we all find it funny when someone does it even though we know they are in pain.
