Three lateral radiographs will be taken with a portable X-ray system provides fixed images from which hard copies are generated. Patient will be served as their own control with reference to the first image, which will be obtained after induction of anesthesia before laryngoscopy and intubation, with the patient in neutral position. A further two images, one with the Macintosh and one with King Vision laryngoscopes. These images will be taken at the time of laryngeal exposure, with the tip of the endotracheal tube passing between the vocal cords.