Surgery of the internal auditory canal occupies an increasingly important place each year and it would, therefore, seem useful to review the main indications for this surgical approach as they are today. They may be classified as follows: (1) Surgery of the internal auditory canal itself. Surgery of the facial nerve, of the vestibular nerve (neurectomy for vertigo), of the cochlear nerve (neurectomy for subtotal deafness accompanied by severe symptoms such as tinnitus or intolerable distortion), of early acoustic neuroma, of the internal auditory canal itself chiefly for stenosis. (2) More extensive surgery. Opening the internal auditory canal may also be necessary during the course of a more extensive operation on (a) the petrous temporal bone, (b) the posterior cranial fossa, and (c) the middle cranial fossa.