When my son came home after his bicycle accident (no helmet) he did not say that he hit his head. He only said he had lost his house keys, went back to where he thought it happened, having remembered hearing some glass breaking. (ummm... egad that must have been his head?!) Later in the ER, the doctor said he didn't have any obvious goose egg. But the CT showed a fracture and a lot of intracerebral bleeding. A few weeks later when I was trimming his hair to even it up I came across a ridge in his right temporal area... the fracture line... that was freeaaky.