Nasal fossae dimensions in the neonate and young infant - A computed tomographic scan study

Objective: To determine normal values in the size of nasal fossae to better delineate the concept of nasal stenosis in young infants with nasal obstruction and without choanal atresia. Design: Case series. Setting: Referral center. Patients: Consecutive sample of 62 infants (aged 0 to 6 months) with no craniofacial anomalies who underwent conventional axial computed tomography scans for a neurologic disorder. Intervention: From computer-stored images, the slices taken at the level of the nasal fossae floor and those just above were examined. The length and 10 measurements of the width of the nasal fossae were used to determine normal values. Results: Most measurements, even the length of the nasal fossae, were positively correlated to the age of the patient (R =.44). In the age 0 to 2 months group, the median length was 29.35 mm (range, 21.3-40.4 mm). It was 31.5 mm in the age 4 to 6 months group (range, 25.3-36.9 mm). The anterior bony aperture seems to be the most accurate distance for the assessment of neonatal nasal fossae stenosis. Its median width was 13.5 mm (range, 8.8-17.2 mm). Large variations characterized the dimensions of the middle nasal fossae and the choanae: median values were 7.6 mm (range, 4.9-13.5 mm) and 14.3 mm (range, 10.8-19.0 mm), respectively. Conclusions: This study defined the normal range of variation for the main dimensions of the nasal fossae in the horizontal plane. These can be used as a basis for determining nasal stenosis in cases of neonatal obstruction.