Figure 42-21 Grades of difficulty in laryngoscopy: grade 1, no difficulty; grade 2, only posterior extremity of glottis visible; grade 3, only epiglottis seen; grade 4, no recognizable structures. (Adapted from Cormack RS, Lehane J: Difficult tracheal intubation in obstetrics. Anaesthesia 39:1105, 1984.)