颞骨岩部结构的定位解剖及临床意义

Anatomical study of the petrous structures in the temporal bone and its clinical significance

目的:为颅底手术中耳蜗的定位、岩尖的磨除范围提供解剖学方法。方法:在12个成人头颅标本上利用颅中窝入路暴露岩内面神经、耳蜗、颈内动脉等结构。观测岩内膝状神经节、颈内动脉(internalcarotidartery,ICA)的膝部、内耳道内侧缘、棘孔与耳蜗之间的解剖关系。结果:耳蜗位于面神经膝状神经节的前下方和岩内ICA膝部的后上方,耳蜗覆盖到ICA膝部的上方。ICA水平段与ICA膝部和内耳道内侧缘连线的夹角为67.1°±4.3°。结论:以棘孔和膝状神经节连线的中点、膝状神经节、内耳道内侧缘形成的三角定位耳蜗。在耳前—颞下窝斜坡手术入路中,在中颅底,过ICA膝部做与ICA水平段成67.1°±4.3°的夹角,在这个夹角内磨除岩尖骨质,不会损伤耳蜗、内耳道及其内容物。耳蜗基底圈至ICA膝部的距离为(0.302±0.016)cm。从前向后磨除岩尖骨质时,ICA膝部后方的骨质磨除不要超过(0.302±0.016)cm,否则会损伤耳蜗。

Objective： To precisely locate the cochlea and to decide the region of the petrous apex drilling in skull base operation. Methods： The facial nerve, cochlea and the internal carotid artery （ICA） in the temporal bones of 12 adult cadveric heads were exposed along the middle cranial fossa approach. The anatomic relationship of cochlea to the geniculate ganglion, the medial lip of the internal acoustic meatus, the ICA genu and the foramen spinosum was studied. Results： Cochlea locates inferiofrontral to the geniculate ganglion of facial nerve, posteriosuperioral to ICA genu. Cochlea covers the ICA genu superiorly. The angle between the horizontal ICA and the line which connects the ICA genu to the medial lip of the internal acoustic meatus is 67.1±4.3°. Conclusions： A new triangle is proposed to precisely locate cochlea, which bounded by the medial lip of the internal acoustic meatus, the geniculate ganglion and the midpoint between the geniculate ganglion and the foramen spinosum. And when drilling petrous apex in the preauricular-inferotemporal fossa approach, an angle could be set up which the horizontal ICA rotated around the ICA genu 67.1±4.3°. In this angle, removing petrous apex can＇t damage cochlea and the internal acoustic meatus. The distance between cochlea and the ICA genu was （0.302±0.016）cm. So the removing bone behind the ICA genu can＇t exceed 0.302±0.016cm.