颞下经岩前硬膜外入路相关中颅窝显微解剖

目的 利用颞下经岩前硬膜外入路研究中颅窝解剖结构之间的关系.方法 国人成人尸头湿标本10例20侧.模拟颞下经岩前硬膜外入路操作.磨除岩尖骨质,暴露并保留内听道(IAC)、耳蜗(Coch)、颈内动脉(ICA).观察并总结各解剖结构之间的关系.结果 (1)弓状隆起(AE)依气化程度不同,可分为3类:平坦型、梯田型和砾石型.前2型AE与上半规管(SSC)的关系容易确定;(2)颞下经岩前硬膜外入路所涉及的中颅窝解剖结构均位于以"三叉神经节"和"膝状神经节"为中心的两个扇形结构中."前扇"由三叉神经及三叉神经节组成,"后扇"由岩浅大神经(GSPN)、AE、IAC构成.ICA及Coch位于"后扇"内.两个扇形由GSPN相联系;(3)IAC位于"后扇"内,GSPN与AE的夹角为122.7°±7.6°(108.1°～137.5°),GSPN与IAC前壁的夹角为46.6°±4.9°(35.0°～55.2°).Coch位于GSPN与IAC前壁的夹角内.结论 两个扇形可以将颞下经岩前入路相关的中颅底解剖结构加以概括,简单直观,便于理解与记忆;磨除岩尖时,IAC的保护选择IAC前壁较安全.

Two fans in middle cranial fossa: microsurgical anatomy of middle cranial fossa through subtemporal-transpetrosal extradural approach

Objective To study the anatomy of the middle cranial fossa through subtemporaltranspetrosal extradural approach. Methods Fixed in formalin, 20 sides of 10 Chinese adult cadaveric heads were filled with red and blue silica gel. Followed the subtemporal transpetrosal extradural approach,the manipulation was done. The extradural trajectory in middle fossa was exposed laterly to the arcuate eminence (AE) and posteriorly to the superior petrosal sinus. The petroclival region was seen after drilling the bone of Day quadrilateral while preserving the internal auditory canal (IAC), cochlea and internal carotid artery (ICA). The anatomy of middle cranial fossa was studied. Results (1) According to the shape and gasification, the arcuate eminence was classified to there types:Smooth-type, terrace-type and gravel-type. The relationship between arcuate eminence and superior semicircular canal was clear in the former two types. (2) The related structures in middle cranial fossa and petrosal bone could be described and linked systematically by two associated fans:anterior fan centered around the gasserian ganglion, posterior fan centered around the geniculater ganglion.(3)The internal auditory canal was in the posterior fan. The angle between GSPN and AE was 122.7°±7.6°(108.1°～137.5°). The angle between GSPN and interior border of IAC was 46.6°± 4.9°(35.0°～55.2°). Cochlea was located in the angle of GSPN and IAC.Conclusion Easier to be understood and momerized, all structures in the middle cranial fossa through subtemporal-transpetrosal extradural approach could be generalized by two fans.Identification of the interior border of IAC is more important in drilling of petrosal apex than that of the axis of IAC.