Microsurgical anatomy and clinical application of sclerotin segment of facial nerve

Objective Tostudythemicrosurgicalanatomyofsclerotinsegmentoffacialnerve 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.