목적: The infraorbital nerve (ION) normally courses through the infraorbital canal (IOC) within the roof of the maxillary sinus. However, there are some anatomic variations of the IOC protruding into the maxillary sinus, which may increase the risk of iatrogenic injury on the ION during sinonasal surgeries. This study aimed to investigate the morphometry of ION and anatomic variations of the IOC in the Korean population. 방법:We performed a retrospective review of 200 consecutive computerized tomography of paranasal sinuses performed at our institution between June 2023 and December 2023. We classified the IOC type according to the A’s classification and investigated the morphometry of the ION: Total IOC length, infraorbital groove (IOG) length, infraorbital foramen- infraorbital rim (IOF-IOR) distance, and infraorbital foramen-pyriform aperture (IOF-PA) distance. Furthermore, we investigated whether the presence of the Haller’s cell was associated with the IOC type. 결과:The prevalence of IOC type was 50% in type 2, 24% in type 1, 18% in type 3, and 8% in type 4 respectively. There were no significant differences in gender or laterality among IOC types. However, the total IOC length was significantly longer in males. There were significant differences in total IOC length and IOF-IOR distance among IOC types. The prevalence of Haller’s cell was not significantly different among IOC types. 결론:IOF-IOR distance is longer in IOC type 3 than in other IOC types, which makes it more vulnerable to iatrogenic injury. Detailed knowledge of the IOC type and the morphometry of ION is necessary for surgeons to avoid unwanted complications during sinonasal surgery.