Development of the nasopharynx: A radiological study of children

The relation between pharyngeal tonsil and the bony nasopharynx determines the nasopharyngeal airway patency. Despite its importance, an anatomical study utilizing advanced imaging has not been conducted. The aim of the study was to evaluate the pharyngeal tonsil and bony nasopharynx depth and their ratio (adenoid-nasopharyngeal ratio [ANR]) with relation to sex and age in the general pediatric population. After excluding reported history of adenoidectomy, acute upper airway illness, allergy, and poor quality, 200 randomly selected head computed tomographies (CTs) of children were evaluated. CTs were divided into five age groups (0–5, 5.1–8, 8.1–11, 11.1–14, and 14.1–17 years). For each CT scan, the pharyngeal tonsil, bony nasopharynx and ANR values were calculated. A significant difference was found in the bony nasopharynx and pharyngeal tonsil depth between the five age subgroups (P ' 0.001). Both bony nasopharynx and pharyngeal tonsil depth significantly increased between the age groups of 0–5 years to 5.1–8 years (4.17 mm increase, P ' 0.001 and 3.47 mm increase, P ' 0.009, respectively). The pharyngeal tonsil depth gradually decreases following the age of 8 years. No difference was found between age groups beyond age of eight for both the pharyngeal tonsil tissue and the bony nasopharynx. The ANR has an upward trend in the age group of 5.1–8 years. No sexual predilection was found. The bony nasopharynx and the pharyngeal tonsil tissue both grow during childhood. Different growth rates result in the narrowest airway in the age group of 5.1–8 years (ANR peak). These growth curves should be taken under consideration when treating pediatric pharyngeal tonsil hypertrophy. Clin. Anat., 33:1019–1024, 2020.