ObjectivesAlthough the mechanisms underlying the initiation and maintenance of inflammation in unilateral maxillary fungal balls (FBs) are poorly understood, the relationship between intranasal anatomy and maxillary FB is thought to play an important role. The aim of this study was to investigate the relationship between anatomic variations and FB.MethodsWe enrolled 140 patients who were composed of 56 patients with FB, 56 patients with unilateral chronic rhinosinusitis (CRS), and 28 patients with no sinus disease. Computed tomography scans were retrospectively analyzed to identify and compare the associated nasal anatomic abnormalities. To measure the volume of the nasal cavity and middle meatus, computed tomography scans were reconstructed into three-dimensional images.ResultsThe relatively larger volume of the middle meatus was associated with the localization of the FB in contrast with the CRS. However, the nasal-cavity volume, nasal valve area, and nasal septal deviation were not significantly associated with localization of FB. The mean volumetric and areal measurements such as nasal cavity, middle meatus, and nasal valve in FB-ipsilateral sides were not significantly different from those in contralateral sides as well as other groups.ConclusionThe middle meatus bears the major part of the inspiratory nasal airflow, and its volume may influence the occurrence of FB.