The Osseous Capsule of the Cochlea, Semicircular Canals, and Internal Acoustic Meatus. The floor of the right middle fossa has been drilled to remove bone and air cells and expose the osseous capsule of the cochlea, semicircular canals, and internal acoustic meatus. The cochlea is located anteromedial to the fundus of the meatus. The superior, lateral, and posterior semicircular canals are situated posterolateral to the fundus of the meatus. The transverse crest separates the fundus of the meatus into upper and lower parts. The facial and superior vestibular nerves course above and the cochlear and inferior vestibular nerves course below the transverse crest. (Image courtesy of AL Rhoton, Jr.)