Right superior view of middle and inner ear structures following removal of a portion of the petrous part of the temporal bone. The cochlea and labyrinth are exposed as are the segments of the facial nerve during its course through the internal auditory canal and medial wall of the tympanic cavity. Note the origin of the greater superficial petrosal nerve at the geniculate ganglion. The opening of the Eustachian tube can be seen at the anterior wall of the tympanic cavity. The superior petrosal sinus can be seen within the attachment of the tentorium cerebelli to the superior border of the petrous bone. The trigeminal nerve can be seen coursing over the petrous apex and expanding into the trigeminal ganglion, which lays upon the trigeminal depression. Also, note the emergence of the middle meningeal artery through the foramen spinosum. (Image courtesy of AL Rhoton, Jr.)