Standard precautions against radiation exposure will be taken, movement of the cervical spines during endotracheal intubation will be studied and recorded with portable X-ray machine. Laryngoscopy will be performed twice, once with the King Vision and once with the Macintosh laryngoscope in random order. For the first device, the patient's mouth will be opened and the tip of the tracheal tube will be introduced into the glottis. The second device will be studied in an identical manner, and intubation will be completed with the second device. The intubators who will participate in the study will receive a standard manikin based training which will be followed with 50 successful endotracheal intubations in the clinical practice with the use of Macintosh and King Vision® laryngoscopes.