Stepwise Exposure of the Petrous Carotid in the Postauricular Transtemporal Approach. E, The facial nerve has been reflected out of view. The promontory has been drilled to expose the cochlea and the vestibule, which are positioned above, posterior, and lateral to the posterior genu. The jugular bulb has been removed to expose the jugular fossa in which the bulb resides. The nerves exiting the jugular foramen have been reflected backward to expose the hypoglossal nerve exiting the hypoglossal canal. F, The bone above the occipital condyle has been drilled to expose the hypoglossal nerve in the hypoglossal canal. The hypoglossal nerve joins the cervical carotid, internal jugular vein, and Cranial Nerves IX to XI in the carotid sheath. G, Overview before opening the dura. The postauricular approach offers the potential for providing retrosigmoid and presigmoid exposure and access to the infratemporal and pterygopalatine fossae, orbit, and subtemporal area. The relationship of the petrous carotid to the cochlea, greater petrosal and trigeminal nerves, and infratemporal fossa is displayed. H, Overview of exposure after opening the dura and elevating the temporal lobe. (Images courtesy of AL Rhoton, Jr.)