Two different cases of FNS, both coronal plane bone algorithm CT images show significant enlargement of the tympanic segment of the facial nerve with the case on the left demonstrating extension of the lesion primarily superiorly and medially, as well as extension into the cochlea, whereas the lesion on the right shows extension primarily inferiorly and laterally, displacing the ossicles, explaining this patient’s presentation with conductive hearing loss and a middle ear mass on clinical examination (at arrows). From Wiggins and Harnsberger (2001). Used with permission.