Radiological classification of the infraorbital canal and correlation with variants of neighboring structures

This study aims to classify the infraorbital canal according to its position related to the maxillary sinus as observed by axial CT. It is a retrospective, cross-sectional study. This study was performed in a tertiary referral center. In this study, axial and coronal CTs of 750 patients were examined and infraorbital canals and neighboring structures were evaluated. Infraorbital canals were then classified according to their positions in relation to the maxillary sinus as seen in axial sections. Morphologic variations of neighboring structures were also noted and their correlations with specific canal types were investigated. Three types of infraorbital canal configurations were identified according to the canal’s relationship with the maxillary sinus: Type 1, the infraorbital canal was totally protruding into the maxillary sinus (12.3 %); Type 2, the infraorbital canal was located at the floor of the maxillary sinus or was partially protruding into the maxillary sinus (51.2 %); Type 3, the infraorbital canal was totally embedded in the maxillary corpus or was bulging on the external face of the maxillary sinus (36.4 %). Concurrence of maxillary sinus septa and infraorbital canal type-1 was found to be statistically significant on both sides (right side p = 0.00, left side p = 0.00). The study radiologically classified the infraorbital canal according to its position as related to the anterior wall of the maxillary sinus, and found that the type where the canal was totally protruding into the maxillary sinus (type-1) had a significant rate of 12.3 %. The rate of the protruded infraorbital canal was doubled with the presence of maxillary sinus septa (25 %).