Our dog Roxie was lying in the street when a car came along.  I called to her frantically, but she didn't get up, and the car went past her.  It seemed to have just missed her, but when I went to her, she seemed to have one of her hind legs was badly out of shape, and I realized that that leg had been run over.  She wasn't crying or reacting in any way until I tried to pick her up, when she reacted in pain.  I was really upset, naturally.