[Surgical anatomy guidelines for the extended transtemporal approach to the cerebellopontile angle]

The extended middle fossa approach to the cerebello-pontine angle was practiced in ten human temporal bones, and the topographical relations of essential structures were studied by exposure of the bony labyrinth. After identification of the greater superficial petrosal nerve and the grey line of the superior semicircular canal landmarks were defined in order to localize the vertical crest (Bill's bar), the ampulla of the superior semicircular canal, the intralabyrinthine part of the facial nerve, the cochlea, and the internal carotid artery. The advantages of the extended middle fossa approach for the preservation of the labyrinthine and cochlear structures together with the safe identification of the facial and cochleo-vestibular nerves are emphasized.