The aim of this study is to analyze the frequency of existence, numbers, and location of the accessory infraorbital foramen (AIOF).In a PubMed search, 166 articles resulted using the term infraorbital foramen (IOF). The abstracts were read, and 15 full-text articles were reviewed. Among them, 13 articles were analyzed.The frequency of the skull containing the AIOF varied (0.8%-27.3%). The overall frequency of the skull having AIOF was 16.9% ± 8.6% (17.0% ± 9.4% in dry skulls and 15.8% ± 3.6% in cadavers). Most (92.2%) of the AIOF were located on the superomedial side of the IOF, whereas 5 (7.8%) were located inferomedially. The AIOFs were found in similar frequency according to the laterality (right, 42.7%; left, 45%; bilateral, 12%; P = 0.794 [binominal test]). The frequency of the AIOF varied according to latitude. Skulls collected greater than 60 degrees had a higher frequency of an AIOF (28.7%) than between 30 and 60 degrees (19.0%) or less than 30 degrees (18.2%) (P = 0.000 [Pearson Chi-squared test], P = 0.000 [trend test]). There was a positive correlation between latitude and frequency of AIOF (y = 0.062x + 18.02, Pearson correlation coefficient = 0.140, P = 0.000).During anesthetization of the infraorbital area or in surgical maneuvering in the maxillofacial region, surgeons should remember the frequency of the AIOF (16.9% ± 8.6%) and its location (92.2% at the superomedial side of the IOF).