The sphenoid bone is located in the middle cranial fossa and has a lot of structures going through its foramina. However, in a skull belonging to the collection of the anatomic laboratory of the University of Rio dos Sinos Valley, an unusual foramen was found. It was placed below the optic canal, in the body of the sphenoid bone, thus connecting the middle cranial fossa with the nasal cavity and it was not yet described in the literature. Observing this, it was decided that the next step should be a search in the collection of another two universities in the Brazilian South and one in the Northeast. The presence of the unknown foramen was checked in dry skulls with their base exposed, verifying its prevalence in the collection of the anatomic labs of the participating universities. Following the inclusion criteria, another 96 skulls were analyzed, looking for the same observed foramen, and was found in another 4 skulls, making a total of 5.15%. Among them, two had presented it unilaterally and the other three, bilaterally. Because the analysis was performed in dry skulls, it was not possible to observe probable structures that could be going through it. Knowing its existence will benefit various researchers and other professionals of the field. Future perspectives for this study will be based on the observation of this foramen in new cadavers donated to these institutions during the dissection and removal of brains to try to see what structures may be passing by it.
