The contact owns a 2015 Ford Explorer. The contact stated while driving 35 MPH while depressing the brake pedal and attempting to come to an abrupt complete stop for a red light, the rear driver seat detached and unhinged. The contact sustained an injury to the back of her head from the detached rear driver seat. The contact stated returned to her residence and called her health provider to make an appointment for the next day where she was informed that she sustained a concussion to the back of the head. The vehicle was not taken to a dealer for diagnosis. The vehicle was not repaired. The manufacturer was not notified of the failure. The approximate failure mileage was 150,000.