后鼓室解剖结构测量观察及临床意义

Measurement of the posterior tympanum and its clinical significance

目的通过研究后鼓室有关解剖结构,及对后鼓室入路手术的径路进行观察、测量,为中耳相关手术入路提供理论参考依据。方法取成人30个干性颅骨的60侧颞骨,用耳科钻完成乳突腔气房"轮廓化",充分暴露后鼓室的各相关结构,在手术显微镜下进行解剖学观察,并对有关结构之间的距离进行测量。结果颞骨标本解剖观察结果,锥隆起至鼓索隆起的距离(3.22±0.41)mm、锥隆起至面神经管直线距离(3.59±0.48)mm、鼓索后小管的长度(9.44±1.65)mm;面神经管锥曲至鼓索隆起间的距离(3.34±0.42)mm、面神经锥曲至水平半规管距离(1.54±0.25)mm、面神经锥曲至后半规管距离(2.15±0.29)mm。面神经垂直段从外向内观察大部分呈后凸弧形下行,但有2例(3.33%)呈直线型垂直下行。面神经镫骨肌支全部从面神经管前壁穿出,鼓索神经自面神经管外发起9例(15%),自面神经管下1/3处分出49例(81.67%),自1/3处分出2例(3.33%)。结论经后鼓室进路手术开放面神经隐窝时,鼓索隆起至面神经管锥曲和至锥隆起的距离可作为开放面神经隐窝的宽度,面神经管与锥隆起可作为手术中互为寻找的依据。术中处理面神经隐窝病变时勿随意磨低锥隆起及鼓索隆起,以免损伤面神经镫骨肌支及鼓索神经。

Objective To measure structures of the posterior tympanum and thus to provide theoretical reference for operation approach related to the middle ear. Methods 60 sides of 30 dry temporal bone specimens had their mastoids outlined by an electric drill, and then the related structure of the posterior tympanum was exposed. Distances of the related anatomic structures were determined under surgical microscopy. Results Distances between pyramidal eminence and chordal eminence and the facial canal were 3.22 ± 0.41 mm and 3.59 ± 0.48 mm, and length of the tympanic chorda posterior tubules was 9.44 ± 1.65 mm. Distances between pyramid segment of the facial canal and chordal eminence, lateral semicircular canal and posterior semicircular canal were 3.34 mm ± 0.42 mm, 1.54 ± 0.25 mm and 2.15 ± 0.29 mm, respectively. The vertical segment of the facial nerve went down on the convex arc and vertically went down only in 2 cases （3.3 ± 3% ）. The mnsculus stapedius all passed through the front wall of the facial nerve. The tympanic chorda nerve came from the facial nerve, outside the canal in 9 cases（ 15% ）, from the inferior one-third in 49 cases （81.67%）, and from the middle one-third in 2 cases （3.33%）. Conclusion When the facial recess is opened, distance from the chordal eminence to the pyramid segment and the pyramidal eminence can be regarded as the width of the facial recess. The pyramidal eminence and the facial canal are regarded as the basis for searching for each other. Pyramidal eminence and chordal eminence should not be lowly abraded in order to avoid damaging the musculus stapedius and chorda tympani nerve when dealing with a facial recess lesion.