后鼓室手术入路的应用解剖学研究

目的　为后鼓室入路手术提供解剖学依据。方法　利用成人 6 0侧颞骨标本 ,用牙科钻磨开乳突腔 ,打开外耳道外侧壁和鼓室盾板 ,充分暴露后鼓室入路手术中有关的解剖结构。以外耳道上棘、面神经管锥曲为测量标志 ,在手术显微镜下 ,对在手术中遇到的解剖结构之间的距离进行了测量。结果　外耳道上棘至砧骨窝、锥隆起、鼓索隆起、面神经管锥曲、外侧半规管、后半规管、前庭窗、蜗窗、匙突、乙状窦垂直部前缘中点、窦膜角的距离分别是 17 19、18 0 2、15 2 2、14 4 9、15 39、17 35、19 5 8、2 0 0 9、2 0 32、15 6 8、18 76mm。面神经管锥曲至鼓索隆起、水平半规管、后半规管的距离分别是 3 33、1 5 3、2 15mm。结论　外耳道上棘、面神经管锥曲是后鼓室入路的重要手术标志 ,鼓索隆起向内 3mm是手术入路的安全区 ,面神经减压术时应避免损伤水平半规管及后半规管等结构

Applied Anatomic Study of Posterior Tympanum Operation Approach

Objective To provide the anatomic data for the operations through posterior tympanum approach. Methods On 60 sides adult temporal bone specimens, the related anatomic structures were well exposed by opening the mastoid cavity and removing the lateral wall of external auditory canal and tympanic scutum. The distances of the related anatomic structure were measured under the surgical microscope. Results The distances from suprameatal spine to incudal fossa, pyramidal eminence, chordal eminence, pyramid segment of facial canal, lateral semicircular canal, posterior semicircular canal, vestibular window, cochlear window, cochleariform process, the midpoint of the anterior margin of the vertical part of sigmoid sinus, sinodural angle were 17.19, 18.02,15.22,14.49,15.39,17.35,19.58,20.09,20.32,15.68 and 18.76mm respectively. The distances from pyramid segment of facial canal to chordal eminence, lateral semicircular canal and posterior semicircular canal were 3.33, 1.53 and 2.15mm respectively. Conclusion Suprameatal spine and pyramid segment of facial canal are the important surgical marks. The area of 3mm inward from the chordal eminence is the safety region for operative approach, the lateral and posterior semicircular canal should be paid to avoid damaging during facial nerve decompression.