Background: Previous studies of variations of the infraorbital foramen (IOF) demonstrated conflicting results regarding to the side and gender in which specific variations occur. Significant differences in some measurement points between genders have been found, whereas, other studies did not report such differences. The presence of an accessory IOF (AIOF) can result in incomplete anesthesia or treatment failure. Previous studies have demonstrated variable results regarding the prevalence of an AIOF ranging from 16.9% to 47.6%.
Objectives: The purpose of this study was to perform a morphological and morphometric study of the IOF and AIOF based on images of 3-dimensional (3D) facial bone computed tomography (CT) scans.
Study design: Retrospective study.
Methods: Identification and analysis of patients who have undergone facial bone 3D CT were performed using Clinical Data Warehouse v 2.5 (CDW, Planit Healthcare, Seoul, Korea). The search term that we used with the CDW for analysis was "facial bone 3D CT."First, the region below the infraorbital rim was examined to determine the presence of the IOF and AIOF. Second, the shape of the IOF was determined and categorized as circular or oval. Third, the vertical (VD) and horizontal (HD) diameters of the IOF were determined. Lastly, the distances between important anatomic landmarks and the IOF were measured.
Results: A single IOF with a circular shape was most common. The HD and VD of the IOF were significantly larger in men than in women. The distance between the IOF and the infraorbital margin was similar between men and women. The distances measured from the lateral nasal aperture (LNA) to the IOF and the anterior nasal spine (ANS) to the IOF, at both sides, were significantly shorter in women than in men. The prevalence of the AIOF on the right and left side was 7.3% and 8.9%, respectively. The most commonly observed position of the AIOF was on the inferior medial side of the IOF.
Limitations: This study had an imbalance in the number of male and female patients.
Conclusions: The size of the IOF was larger in men than in women. The distance of the IOF from the infraorbital margin was similar for men and women, whereas, the distances between the IOF and the ANS and the IOF and LNA were shorter in women than in men.
Keywords: diameter; facial bone CT; infraorbital foramen; Accessory infraorbital foramen.