A 65-year-old woman and her 9-year-old granddaughter were in a train crash. The sustained only minor injuries, but at the moment of impact her grandmother sharply on the metal bar of the seat in front of her. She was taken to the hospital running from her nose, and she was complaining of inability to smell anything. The grandmother had fractured a cranial bone. Surgery to repair the damage struck her nose with clear fluid X rays showed that was delicate and difficult, and the woman's sense of smell never returned. Which cranial bone was fractured?