The anatomy of the extratemporal facial nerve is shown relative to the cartilage pointer and tympanomastoid suture. The intratemporal nerve is shown relative to the digastric ridge, labyrinth, tympanic annulus and middle ear muscles. Measurements are in millimeters. Note the labyrinthine segment is cradled in the space between the superior canal and the cochlea. Note the relation in the internal meatus to the cochlear and vestibular nerves.

Review the relationships of the lower cranial nerves in the posterior fossa and in the jugular foramen.

The dimension of the internal meatus and relation to the superior canal is shown. 3 and 2 millimeter burrs are shown to demonstrate how they are used to approximate the dimension of the internal canal when drilling.

Cranial nerves V thru XII are sequentially shown at the brainstem and at their distinct exits from the posterior fossa. Their relationships to one another and to vascular structures of the posterior fossa can be appreciated.