This device serves to immobilize the head and neck area of people who have obvious or suspected cervical trauma. Primarily, it consists of a metal frame with clear plastic side plates, for preventing the movement of the user's head, and it also includes a channel with a set screw, for holding the frame...http://www.google.de/patents/US4640275?utm_source=gb-gplus-sharePatent US4640275 - Head restraint for backboards
