This document discusses disorders and topodiagnostic tests of the facial nerve. It covers several infections that can cause facial nerve disorders like Herpes zoster oticus and various types of ear infections. Trauma from temporal bone fractures, iatrogenic injury from ear/mastoid/parotid surgery, or facial trauma can also cause facial nerve disorders. Topodiagnostic tests like the Schirmer test, stapedial reflex test, taste test, and submandibular salivary flow test can help locate the site of lesion or injury to determine the etiology and appropriate surgical treatment.