In addition to correct positioning, several other general principles are critical for success: Visualizing the epiglottis Visualizing the posterior laryngeal structures (ideally, the vocal cords) Not passing the tube unless tracheal insertion is ensured The conventional laryngoscope is designed to be held in the left hand, and the blade is inserted into the mouth and used as a retractor to displace the mandible and tongue up and away from the laryngoscopist, revealing the posterior pharynx.