Fig. 2. Normal upper airway in 1-month-old boy with vascular ring.

Sagittal inspiratory (A) and expiratory (B) volume-rendered CT images demonstrate normal appearance of upper airway. U separating nasopharynx from oropharynx is noted. U contributes to velopharyngeal closure with other velopharyngeal muscles that is indispensable for normal swallowing and speaking. As shown in these merged volume-rendered images, bone structures can be added to airway structures to facilitate anatomical correlations. To note, upper airway dimension diminishes normally from inspiration to expiration. Patient was sucking on pacifier (asterisks) during CT examination. U = uvula