cormack-lehane classification system cormack-lehane classification system the cormack-lehane system classifies views obtained by direct laryngoscopy based on the structures seen. it was initially described by r.s. cormack and j. lehane in 1984 as a way of simulating potential scenarios that trainee anaesthetists might face. a modified version that subdivided grade 2 was initially described in 1998. modified cormack-lehane classification. gradedescriptionapproximate frequencylikelihood of difficult intubation 1full view of glottis68-74%<1% 2apartial view of glottis21-24%4.3-13.4% 2bonly posterior extremity of glottis seen or only arytenoid cartilages3.3-6.5%65–67.4% 3only epiglottis seen, none of glottis seen1.2-1.6%80–87.5% 4neither glottis nor epiglottis seenvery rarevery likely