The link between the facial growth and airway function has been a subject of controversy in orthodontics for many years. This study investigates how well lateral cephalometric headfilms depict three-dimensional upper airway structures. Subjects are 11 normal adolescent children, ages 7-16 years old. Airway information over the same anatomic area in the nasopharynx is compared between lateral cephalometric headfilms and three-dimensional cone beam computed tomography (CT) scans. Intra-subject proportion of airway volume to area shows moderate variability. CT airway volume shows more variability than corresponding headfilm airway area.