I was traveling approximately 50 mph on a highway when we were rear-ended. The car spun around and we were both thrown forward due to the malfunctioning of both the driver and passenger seat belts. Further inspection found the rear seatbelts as well did not function properly. Both the driver and front passenger seats reclined and broke during the impact of the accident. The passenger sustained head injuries and had to be taken by ambulance to the hospital. The driver's left arm was injured.