Doubled foramen rotundum and maxillary nerve fenestration.

Even though the doubled foramen rotundum (FR) can be identified once within the literature, there are no details of the contents at that level. We present here an anatomical case demonstrating the maxillary nerve (MN) duplication at the level of an unilateral doubled FR: the accessory nervous trunk of the MN separately left the trigeminal ganglion on the outer side of the MN main trunk and coursed beneath the main trunk of the MN canal, within the sphenoidal greater wing, to join infero-medially that main trunk at the entrance in the pterygopalatine fossa. Overall, the MN appeared as fenestrated, with a thin bony plate separating the two cords of the nerve traversing the skull base. Previously undocumented, the MN duplication may interfere with various surgical exposures interfering with the foramen rotundum and may explain atypical sensory syndromes and functional impairment during skull base trauma or anesthesia.