面神经颅内段的显微外科解剖学研究

目的探讨面神经颅内段的显微解剖,为临床手术提供解剖学参数.方法应用10%甲醛充分固定的成人尸头标本10例20侧;漂白干颅骨10例20侧.结合侧方手术入路对面神经及其毗邻结构进行测量和拍照.结果面神经颅内段分为五段,即脑桥小脑角段、内耳道段、迷路段、鼓室段和乳突段.脑桥小脑角段和内耳道段与位听神经伴行;迷路段最短最细,约3.8mm±0.7mm长;鼓室段与骨迷路和中耳关系密切;乳突段长约15.5mm±1.9mm,经茎乳孔出颅.结论枕下乙状窦后入路中可利用第四脑室脉络丛定位面神经脑干端;经岩前人路中可利用弓状隆起和岩浅大神经定位面神经内耳道段和迷路段部分鼓室段骨壁缺如,面神经直接裸露在岩骨表面;外半规管至二腹肌嵴前端是面神经乳突段的标志线.

Microsurgical anatomy of intracranial segment of facial nerve

OBJECTIVE: To study the microsurgical anatomy of intracranial segment of facial nerve so as to provide anatomic parameters for clinical operation. METHODS: Ten adult cadavers were fixed and perfused with color silicon. Facial nerves of these cadavers were observed and measured under operative microscope according to lateral cranial base operative approach. Ten dry skulls were dissected to observe the relationships of osseous structures. The anatomic relationship and data of different segment of facial nerve were obtained respectively. RESULTS: The facial nerve was divided into five segments, namely, cerebellopontine angle segment, internal acoustic meatus segment, labyrinthine segment, tympanum segment and mastoid segment. The cerebellopontine angle segment and internal acoustic meatus segment paralleled the vestibulocochlear nerve. The labyrinthine aegment is the finest and shortest with the lebgth of 3.8 mm +/- 0.7 mm. The tympanum segment is closely related with osseous labyrinth. The mastoid segment, 15.5 mm +/- 1.9 mm long, leaves the cranium from stylomastoid foramen. CONCLUSION: Facial nerve can be located with choroid plexus of the fourth ventricle in retrosigmoid approach. Arcuate eminence and greater superficial petrosal nerve are important mark to locate internal acoustic meatus segment and labyrinthine segment in antepetrosal approach. Tympanum segment may be exposed on the surface of petrous bone in some cases. The line between lateral semicircular canals and crista of digastric muscle is the mark of mastoid segment.