Imaging the facial nerve: A contemporary review of anatomy and pathology.

ABSTRACT

PURPOSE: The facial nerve is the seventh paired cranial nerve which anatomically can be divided into six distinct segments. There are a wide range of pathologies that may occur along each segment of the nerve. The aim of this pictorial review is to untangle the complex appearances of the facial nerve, both in its normal anatomical course and when affected by pathology. METHOD: This review takes an evidence-based segmental approach to the evaluation of the facial nerve in terms of its anatomy and clinical features of common pathologies affecting specific segments of the nerve. The typical multimodal radiological findings of common facial nerve pathologies are included in the review using imaging from select pathologically confirmed cases. RESULTS: A wide range of pathologies ranging from congenital abnormalities to inflammatory, infective and neoplastic processes can affect the facial nerve. As select segments of the nerve are better evaluated on certain imaging modalities a clear understanding of the anatomy and clinical features associated with specific facial nerve pathologies enables the radiologist to tailor the imaging test to best answer the clinical question. CONCLUSIONS: This review provides a segmental clinical-radiological approach to imaging the facial nerve. In addition, recent developments in facial nerve imaging that may come into mainstream use in the near future are touched upon.