Superior view of the right middle fossa floor after partial petrosectomy. The facial and vestibulocochlear nerves exit the brainstem at the pontomedullary junction and course laterally into the internal acoustic meatus, a foramen in the petrous part of the temporal bone inferior to the tentorium and the superior petrosal sinus. At the geniculate ganglion, the greater superficial petrosal nerve traverses anteromedially over the petrous segment of the internal carotid artery on the floor of the middle cranial fossa ultimately passing under the mandibular division (V3) of the trigeminal nerve. Immediately laterally is the foramen spinosum where the middle meningeal artery enters the skull. The facial nerve continues after the geniculate ganglion as the tympanic and mastoid segments inferolaterally. (Image courtesy of AL Rhoton, Jr.)