Abstract:

    Objective　To study the microsurgical anatomy of sclerotin segment of facial nerve so as to provide anatomic parameters for clinical application.  Methods　Ten adult cadavers were fixed and perfused with color silicon. Facial nerves of these cadavers were observed and measured under operating microscope according to the lateral cranial base operative approach. Ten dry skulls were dissected to observe the relationships of osseous structures. The anatomic relationship and data of different segments of facial nerve were obtained respectively.  Results　The facial nerve was divided into four segments, namely, internal acoustic meatus segment, labyrinthine segment, tympanum segment and mastoid segment. The cerebellopontine angle segment and internal acoustic meatus segment of facial nerve paralleled the vestibulocochlear nerve. The tympanum segment was closely related with osseous labyrinth and left the cranium from stylomastoid foramen. Conclusions　Arcuate eminence and greater superficial petrosal nerve are important mark to locate internal acoustic meatus segment and labyrinthine segment in antepetrosal approach. Approach by the labyrinthine of Bill Crest is an important indicator of internal acoustic meatus segment of facial nerve. The angle bisector of Arcuate eminence and greater superficial petrosal nerve is the best marker to locate the internal acoustic meatus from middle cranial fossa.

Key words: Facial nerve, Temporal bone, Neuroanatomy