The<unk><unk><unk>  classifies views obtained by direct laryngoscopy based on the structures seen. It was initially described by R.S.<unk>  and J.<unk>  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<unk><unk>  classification. Grade Description Approximate frequency Likelihood of difficult intubation 1 Full view of glottis 68-74% <1% 2a Partial view of glottis 21-24% 4.3-13.4% 2b Only posterior extremity of glottis seen or only arytenoid cartilages 3.3-6.5% 65-67.4% 3 Only epiglottis seen, none of glottis seen 1.2-1.6% 80-87.5% 4 Neither glottis nor epiglottis seen very rare very likely
Cormack-Lehane classification system
Nissen-Lie classification
Herscovici classification
Frykman classification
Spaulding classification
Ruedi–Allgower classification
Pipkin classification
Siewert classification