Figure 2.

The 3-3-2 Rule. (A) More than 3 fingers between the open incisors, indicating patient’s mouth opens adequately to permit the laryngoscope to reach the airway; (B) more than 3 fingers along from mentum to hyoid bone, which indicates enough space for intubation; (C) more than 2 fingers from the laryngeal prominence to hyoid bone, less than 2 fingers indicate high position of pharynx in the neck and likely difficult exposure with direct laryngoscope.