Ⅶ、Ⅷ颅神经复合束的连续切片观察

Observation of serially sectioned seventh and eighth cranial nerve complex

采用连续切片观察手段，研究人类Ⅶ、Ⅷ颅神经从内耳道底到脑干附着处的行径中，各个横断面在三维空间的变化。结果显示：Ⅷ颅神经分支由分散渐趋融合，在桥小脑角内呈神经干状。耳蜗神经在内耳道围绕前庭神经纵轴９０°旋转，右耳顺时针、左耳逆进针，与内耳道底螺旋孔径的方向完全一致，这可能是其发生原因。施行保留听力的前庭神经切断术时，尽可能选择暴露内耳道的术式。

Abstract The three-dimensional changes of every transection of the seventhandeighth cranial nerves from the fundus of the internal auditory canal tothe attachment of the brain stem in human were studied by means of serial section observation,The resuIts showed that the divi-sions of the eighth cranial nerve changed gradually from divergence to fuse and became a nerve trunk within the cerebellopontine angle, The cochlear nerve rotated 90°around the longitudinal axis of the vestibular nerve within the internal auditory canal.The right ear ro-tation wasclockwise and the left was counterclockwise, and were in consistent with the di-rection of tractus spiralis foraminosus on the fundus meatus acustici interni. This could be the reason of the rotation. The vestibular neurectomy was as performed as possible by exposing the internal auditory canal for the sake of preserving hearing.