Steady but gentle force is generally needed to advance an ETT over the FOS, first through the nose and then into the trachea through the larynx. If the ETT were to pass smoothly no change in force is generally needed as it goes through the larynx. During advancement over the FOS, if ETT came to an abrupt stop and then the same steady force was insufficient to advance the ETT through the larynx it was defined as "hung up". If sudden resistance to passage through the larynx was encountered indicating that the ETT is hung up at the laryngeal inlet, it was then withdrawn about 2 cm, rotated 90° counterclockwise and readvanced through the larynx and observation was made if CCR maneuver leads to smoother passage of the ETT through the larynx into the trachea without it getting hung-up.