Acoustic rhinometry in pre-school children

Acoustic rhinometry was performed in 35 normal nose-breathing children between 3 and 6 years. The average cross-sectional areas at the nasal valve, at the anterior end of the turbinates, and in the nasopharynx were 0.34±0.06 cm², 0.35±0.08 cm² and 1.37±0.48 cm² respectively. The average minimal cross-sectional area was 0.29±0.06 cm². The minimal cross-sectional area was located at the nasal valve in 14 and at the anterior end of nasal tubinates in 21 of the 35 children. As would be expected, the cross-sectional areas at different sites of the nasal cavity increased with increasing age of the children. But, whereas the minimal cross-sectional area increased by 0.024 cm² per year, the nasopharyngeal cross-sectional area increased by 0.20 cm² per year. No significant differences were found between boys and girls. Measurements of the posterior nasal and nasopharyngeal cross-sectional areas were unreliable, whenever the minimal cross-sectional area was less than 0.2 cm². Furthermore, assessment of the nasopharynx may be difficult because of involuntary movements of the soft palate.