颅中窝入路内耳道定位的应用解剖学

A clinical anatomical study on identification of the internal auditory meatus in middle cranial fossa approach

目的经颅中窝入路,以锤骨头为定位标志,测量其与内耳道及其周围重要结构的位置关系,定位内耳道。方法10%甲醛固定成人头颅标本12具(23侧),经颅中窝入路行显微解剖,显露棘孔,面神经管裂孔,岩浅大、小神经,面神经,锤骨头,弓状隆起,岩上窦,半规管和内耳道等,首先以"蓝线法"定位内耳道,测量相关数据,再以锤骨头为定位标志定位内耳道,并测量记录其与周围重要结构的关系。结果上半规管"蓝线"与内耳道长轴夹角为58.52°±4.84°。经锤骨头中心向岩骨(岩上窦)长轴引垂线AB,再经锤骨头在垂线AB前内30°(28.93°±6.07°)引直线BC,该直线上距锤骨头(6.69±1.10)mm可定位内耳道底,距锤骨头(20.1±1.48)mm可定位内耳门中点。结论经颅中窝入路,传统定位标志存在变异时,可以锤骨头定位内耳道及周围重要结构。

OBJECTIVE The head of malleus （HOM） was regarded as the landmark for the middle cranial fossa approach, and its relationship with internal auditory meatus（IAM） was measured. The purpose of this study was to find a safe method to locate IAM. METHODS Twelve heads of adult cadaver fixed with 10 % formaldehyde （23 sides） were microsurgically dissected from the middle cranial fossa approach. The foramen spinosum, Ferrein＇s foramen, greater petrosal nerve, lesser petrosal nerve, facial nerve, HOM, arcuate eminence, superior petrosal sinus, semicircular canal, and IAM were exposed. First, blue lines method was used to locate IAM, Second, HOM as the landmark was used to locate IAM. RESULTS The angles between the SSC and the longitude axis of IAM are 58.52° ±4.84° o A perpendicular line （AB） was drew from the center of HOM to the longitude axis of the temporal bone （the longitude axis of the superior petrosal sinus）, line BC was drew from the anterior 30° （28.93° ± 6.07° ） to the line AB. On the line BC, fundus of IAM can be located （6.69± 1.10） mm medial to HOM, the center of the internal acoustic pore can be located （20.1 ± 1.48）mm medial to HOM. CONCLUSION In the middle cranial fossa surgery, HOM can be used to locate IAM and its surroundings structures when traditional landmarks are unrecognized.