Cormack-Lehane grading scheme for laryngoscopy

Difficulty of direct laryngoscopy correlates with the best view of the glottis, as defined by the Cormack-Lehane scale. With this scale, a grade I view connotes a full view of the entire glottic aperture, grade II represents a partial glottic view, grade III represents visualization of the epiglottis only, and grade IV represents inability to visualize even the epiglottis.