A, The cerebellum has been elevated to expose the nerves in the cerebellopontine angle. A large petrosal vein blocks access to the suprameatal area. B, The superior petrosal vein has been divided to expose the suprameatal tubercle located above theporus of the internal acoustic meatus and lateral to the trigeminal nerve. C, The dura over the suprameatal tubercle has been removed in preparation for drilling. D, Removing the suprameatal bone, including the tubercle, extends the exposure along the posterior trigeminal root by approximately 1 cm and increases access to the front of the brainstem and clivus. (Images courtesy of AL Rhoton, Jr.)