Cormack and Lehane Classification

The Cormack and Lehane classiﬁcation (1984) is the original, and most widely used classification of laryngeal view and is shown in Fig 1.

Grade 1	Most of the glottis is visible
Grade 2	At best almost half of the glottis is seen, at worst only the posterior tip of the arytenoids is seen
Grade 3	Only the epiglottis is visible
Grade 4	No laryngeal structures are visible

Table 1 Cormack and Lehane classification

The grade is the best view achieved
External manipulation and backward, upward, rightward pressure (BURP ) may be used

Modifications to this classification have been described.

Fig 1 Cormack and Lehane classification

Modifications to the classification

The Cormack and Lehane classification correlates only moderately with measures of difficulty with intubation. For instance, an easy Grade 2 is no harder to intubate that a Grade 1, but a difficult Grade 2 is as awkward as an easy Grade 3.

Modifications have been described as follows:

Grade 2a	Glottis is visible
Grade 2b	Glottis not visible
Grade 3a	Bougie possible
Grade 3b	Bougie not possible

Table 2 Cormack and Lehane modified classification

Difficulty with intubation is likely if the glottis cannot be seen and insertion of a gum elastic bougie is not possible, i.e. Grade 3b and 4. This represents less than 20 % of Grade 3 views.