The position of the larynx in children and its relationship to the ease of intubation.

Lateral radiographs of the upper airway of children aged from birth to puberty were used to determine the changes in position, with growth, of the tip of the epiglottis, the hyoid, the glottis, and the inferior margin of the cricoid cartilage. There is a marked descent of these structures relative to the cervical spine during the first two years of life. Their position then remains fairly static until puberty, when further descent of laryngeal structures occurs. Using the same methods to determine ease of laryngoscopy with the head and neck in different positions it was shown that in infants the best view is obtained with the atlanto-occipital joint fully extended and the head and shoulders on a flat surface. In adults the best view is obtained with the atlanto-occipital joint fully extended and the head resting on a low pillow. Anatomical explanations for these observations are presented.