[Imaging of the facial nerve and the petrous apex].

From its origin in the pons to its extracranial exit with a long intrapetrous course, the facial nerve raises various diagnostic problems related to the site and extent of the lesions, which involves the whole field of petrous pathology. The study of the pathology of the neighbouring petrous apex completes this regional analysis. Today, in accordance with the anatomical loco-regional complexity, MRI is the predominant modality of diagnostic imaging (but must be associated with CT to allow the more accurate detection of subtle bone changes); it will be at best directed by the clinical and functional data which reflect the underlying pathophysiologic mechanisms.