Does nasal septal deviation influence adult posterior choanal size?

Despite the development of modern imaging techniques, no study has been carried out to establish the normal size (particularly the area) of the adult posterior choanae. In this study we present our findings of the normal anatomical sizes of the adult posterior choanae and its relationship to septal deviation, by analysing MRI images of 70 patients. Coronal sections through the sphenoid rostrum and axial sections through the nasal septum were used. There were 32 males and 38 female patients. The age ranged between 18 and 73 years (mean 35.6). Our results show that the posterior choanal dimensions were as follows: right area: 1.35-6.1 cm2 (mean 2.7 cm2); left area: 1.4-5.9 cm2 (mean 2.7 cm2); right width: 0.9-2.1 cm (mean 1.5 cm); left width: 0.9-2.2 cm (mean 1.5 cm); right height: 2.5-4.0 cm (mean 2.6 cm); and left height: 1.5-4.0 cm (mean 2.5 cm). Chi-square analysis showed no statistically significant differences between left- and right-sided measurements. Twenty-three patients had a deviated septum towards the left side, 22 patients towards the right side, and 25 patients had no septal deviation. Chi-square analysis showed no statistical correlation between deviation of the nasal septum and any of the three dimensions of the posterior choanae studied.