The 3-3-2 rule for identifying a difficult airway

The spatial relationships described here are important determinants of successful direct laryngoscopy. The normal distances shown suggest laryngoscopy would not be difficult for this patient.

(A) The patient can open their mouth sufficiently to admit 3 of their own fingers.

(B) The distance between the mentum and the neck/mandible junction (near the hyoid bone) is equal to the width of 3 of the patient's fingers.