Morphology and Navigational Landmarks of the Cranio-orbital Foramen in a Portuguese Population

PURPOSE: The cranio-orbital and accessory foramina are located in the lateral wall of the orbit and adjacent to the superior orbital fissure. In the literature, there is a lack of consistency concerning the location and morphology of these foramina in different populations. Therefore, considering its clinical importance during orbital surgeries, it was the authors' aim to determine the incidence, location, and number of cranio-orbital and accessory foramina in a Portuguese population and compare the findings with data from other studies. METHODS: A total of 310 orbits from 155 dry skulls from the collection of the Museum of Anatomy of the Faculty of Medicine of Porto were studied. The characterization of both cranio-orbital and accessory cranio-orbital foramina was performed. RESULTS: The cranio-orbital foramen was present in at least 1 orbit per skull in 58.17% with a median diameter of 0.60 ± 0.33 mm. No relation was found between the presence of this foramen and the gender of the individuals or a tendency for laterality. However, it was found that the presence of 1 or more accessory foramina was related to higher diameters of the cranio-orbital foramen. CONCLUSIONS: There might be a relationship between the localization, diameter, and communication of foramina with the cranial fossae. Foramina located on the greater wing of the sphenoid bone presented a larger diameter and communicated with the middle cranial fossa. High diameters of the main vessel in the cranio-orbital foramen may imply more developed branches and collateral irrigation of the orbital structures using 1 or more accessory foramina. Surgeons should be aware of the location of the cranio-orbital foramen to reduce potential sources of hemorrhage during orbital dissections.