Predicting Difficult Endotracheal Intubation Using the Equation of Bellhouse and Dore

Angle in degrees with the neck maximally extended and the mouth open between lines running.

(1) along the occlusal surface of the maxillary teeth to the most anterior aspect of the body of the first cervical vertebra (lower anterior edge in the midline) and

(2) from the most anterior aspect of the body of the first cervical vertebra to antero-inferior border of the body of the sixth cervical vertebra.

Distance in cm for a perpendicular line drawn from the lower genial tubercle of the mandible to the line connecting the upper incisor teeth to the corniculate cartilage

Distance from the anterior to posterior edge of the tongue in the midline