人工耳蜗植入术相关的面神经隐窝及后鼓室应用解剖研究

目的:通过对人工耳蜗植入术相关的面神经隐窝及后鼓室解剖结构进行观察测量,为人工耳蜗植入术中避免面神经、鼓索神经等损伤及准确定位鼓阶开窗口提供理论参考。方法:对20侧成人颞骨标本进行解剖,模拟经面神经隐窝入路人工耳蜗植入术,在手术显微镜下观察、测量与人工耳蜗植入手术相关的解剖数据。结果:外耳道后上棘至砧骨短脚之间的距离为(12.44±0.51)mm;鼓索神经发出点至茎乳孔之间的距离为(2.67±0.51)mm;砧骨短脚至鼓索神经发出点之间的距离为(15.22±0.83)mm;面神经隐窝最宽处至砧骨短脚之间距离为(6.28±0.41)mm;面神经隐窝最宽处至鼓索神经发出点之间距离为(9.81±0.71)mm;面神经隐窝最大宽度为(2.73±0.20)mm;镫骨头水平面神经隐窝宽度为(2.48±0.20)mm;圆窗水平的面神经隐窝宽度为(2.24±0.18)mm;锥隆起至圆窗膜前缘之间的距离为(2.22±0.21)mm;镫骨头至圆窗膜下缘之间的距离为(2.16±0.14)mm。结论:利用面神经垂直段并非一条直线垂直下行,而是向后有一拱形的弧度,因此面神经垂直段弧度最大位置是打开并充分开放面神经隐窝起始位置;术中切开耳蜗底回的位置位于锥隆起前下方约2.22mm。     

面神经隐窝进路骨性通路解剖及人工耳蜗植入术鼓阶开窗法

目的探讨面神经隐窝进路人工耳蜗植入术骨性通路的显微解剖和鼓阶开窗的立体定位方法,该手术进路骨性通路大小对人工耳蜗植入术的影响。方法对6例成人尸头12侧颞骨行颞骨高分辨率CT扫描，在手术显微镜下模拟经面神经隐窝进路行人工耳蜗植入术，观察和测量面神经隐窝进路骨性通路和鼓阶开窗口的大小以及鼓阶开窗处与面神经、镫骨头、锥隆起、圆窗、匙突等解剖结构的距离，数据进行统计学处理。结果12侧颞骨标本中，颞骨CT观察到面神经隐窝气房11侧（91.7%），1侧无明显气房。面神经隐窝进路骨性通路内外宽度为（2.94±0.28）mm，上下高度为（8.79±0.88）mm，深度为（3.54±0.17）mm，面积为（20.32±3.19）mm2；鼓阶开窗口直径为（1.27±0.21）mm，植入鼓阶内电极长度为（26.2±1.82）mm，鼓阶开窗点与面神经水平段、面神经乳突段、锥隆起、镫骨头、匙突的距离分别为（4.22±0.39）mm、（7.25±0.26）mm、（3.40±0.44）mm、（3.82±0.46）mm和（5.10±0.60）mm。结论颞骨CT可了解面神经隐窝气房情况，面神经隐窝进路骨性通路的大小影响人工耳蜗植入术电极插入，圆窗龛、圆窗、镫骨头、锥隆起、匙突等解剖结构可作为鼓阶开窗的参考标志。     

幼儿面神经的中耳手术解剖学研究

目的研究面神经隐窝入路手术相关的幼儿面神经解剖学特点,为开展幼儿中耳手术及人工耳蜗植入手术提供参考数值。方法对14具(28侧)幼儿尸头颞骨面神经隐窝及后鼓室结构进行解剖学观察,测量面神经隐窝入路手术相关的面神经解剖学特点和相关数值。结果面神经隐窝最小者1.82mm,但存在个体差异。鼓索神经到面神经锥曲段、垂直段的距离分别为(3.79±0.45)mm、(2.23±0.57)mm,锥隆起至面神经锥曲段、水平段、垂直段的距离分别是(2.79±0.60)mm、(2.17±0.42)mm、(3.90±0.59)mm,面神经垂直段至圆窗龛前缘中点的距离(4.83±0.70)mm。结论本文为幼儿中耳手术提供了有用的面神经相关参考数据,对手术中避免面神经等重要结构的损伤有重要意义。     

经乳突面隐窝入路后鼓室相关手术的临床解剖学研究

目的探讨经乳突面隐窝入路后鼓室人路的相关解剖,进行观察测量,为该入路手术提供解剖学资料。方法成人头颅福尔马林泡过6例12侧,在放大10倍的手术显微镜下模拟中耳乳突面隐窝后鼓室入路手术,观察和测量了外耳道上棘、面神经、面隐窝、锥隆起、圆窗、卵圆窗,岬小桥、岬后脚、等相关的解剖结构,数据进行统计学处理。结果外耳道上棘至砧骨短脚的平均距离为20.06mm,外耳道上棘至面神经锥段中点平均距离为17.28 mm,面神经锥段中点距外耳道后壁垂直距离平均为4.67mm,面神经水平段平均长12.30 mm,面神经垂直段平均长16.31 mm.面神经水平段与垂直段的夹角平均为111.5°,鼓索神经与面神经垂直段的夹角平均为23.9°锥隆起至圆窗龛的平均距离为4.46 mrn,锥隆起到镫骨头平均距离2.62mm,锥隆起到砧骨窝平均距离4.43mm,卵圆窗至圆窗龛的平均距离为3.84mm,砧镫关节至圆窗龛的平均距离为3.89mm面神经锥段中点到卵圆窗平均距离8.10mm;面神经锥段中点到岬小桥与岬下脚下端的距离分别是(4.85±0.45mm),(6.21±0.52mm);鼓索神经和面神经垂直段夹角平均为48.3°,水平半规管与面神经水平段夹角平均为19.5°,面神经水平段与垂直段夹角平均为111.5°。结论中耳乳突入路手术中部分重要解剖结构位置恒定,重要解剖结构间距离及角度在一定范围内变化,熟悉其解剖关系,可以完全的清楚病变,又可以指导临床手术,避免手术损伤。     

锥上间隙的颞骨HRCT和术中观察

目的确定锥上间隙的位置及出现率,以协助慢性中耳炎患者面神经术中定位;同时评价颞骨HRCT对锥上间隙的诊断价值。方法收集280例慢性中耳炎患者术前颞骨连续HRCT图像及同期无明显耳部疾病行颞骨HRCT检查的门诊病人的颞骨连续HRCT图像160例(对照组),通过术中观察和HRCT图像观察,确定锥上间隙的位置及出现率。结果锥上间隙位于后鼓室面隐窝骨壁上,砧骨窝和鼓窦入口下方,鼓索嵴上方,面神经管锥曲段及锥隆起外侧,后鼓环内侧。锥上间隙在对照组HRCT图像上、慢性中耳炎患者术中、手术耳术前HRCT图像上的出现率分别为:76%(122例),68%(190例),58%(162例)。在锥上间隙存在的HRCT图像上(284例),87%(247例)的病例可在后半规管层面观察到该间隙。结论锥上间隙位于面神经锥曲段外侧,两者的位置关系密切且相对固定。锥上间隙连同面神经定位的常规解剖标志对中耳手术中面神经锥曲段的定位有一定的提示作用。然而,当锥上间隙不典型时,颞骨HRCT对锥上间隙的诊断价值是有限的。     

经乳突后鼓室入路相关手术的解剖学研究

目的:探讨中耳乳突后鼓室入路的相关解剖,收集解剖数据,为该入路手术提供解剖学基础。方法:国人成人头颅湿标本20例40侧,在放大8倍的显微镜下模拟中耳乳突后鼓室入路手术,观察和测量了外耳道上棘、面神经、面隐窝、锥隆起、圆窗、卵圆窗等相关的解剖结构,数据进行统计学处理。结果:外耳道上棘至砧骨短脚的平均距离为19.14 mm,外耳道上棘至面神经水平段与垂直段交点的平均距离为16.30 mm,面神经水平段与垂直段交点距乳突表面的平均距离为20.84 mm,面神经水平段与垂直段交点距鼓索神经发出点平均距离为11.28 mm,面神经水平段与垂直段交点距外耳道后壁的平均距离为4.40 mm,面神经水平段平均长11.60 mm,面神经垂直段平均长15.30 mm,锥隆起至圆窗龛的平均距离为4.46 mm,卵圆窗至圆窗龛的平均距离为3.74 mm,砧镫关节至圆窗龛的平均距离为3.80 mm;面神经水平段与垂直段的夹角平均为110.4°,鼓索神经与面神经垂直段的夹角平均为24.8°,水平半规管与面神经水平段夹角平均为17.5°,砧骨长脚与后拱柱夹角平均为46.0°。结论:中耳乳突入路手术中部分重要解剖结构位置恒定,重要解剖结构间距离及夹角在较小的范围内变化,熟悉其解剖关系,可以指导临床手术,避免手术损伤。     

面神经垂直段及其周围结构的临床应用解剖

目的探讨颞骨手术中面神经垂直段的走行特点及其定位方法。方法应用30例(60侧)成人尸头标本,(其中3例新鲜标本,27例10%福尔马林固定标本)。在手术显微镜下模拟乳突部位手术,暴露面神经垂直段及其周围结构,观察面神经垂直段的走行特点,与周围结构的关系以及面神经管周围的骨质变化特点。结果面神经垂直段长度(16.31±1.29)mm,面神经垂直段至后半规管距离(2.65±0.85)mm,面神经垂直段至骨性外耳道口距离(17.28±1.09)mm,面神经垂直段至颈静脉球距离(3.58±1.32)mm,面神经垂直段至外耳道后壁距离(4.67±0.39)mm,面神经垂直段至乙状窦距离(6.42±2.65)mm.面神经隐窝外侧气房存在者88.33%,面神经隐窝外侧气房位于面神经管外0²mm.接近面神经管部位血运丰富,为营养面神经的微血管所在.锥隆起在面神经管稍靠内侧,附着在面神经管内1/3以内位置,面神经垂直段位于二腹肌嵴的前端并稍靠内。鼓乳裂消失就接近面神经垂直段。结论面神经隐窝外侧气房、锥隆起、二腹肌嵴、鼓乳裂等,能够帮助我们定位面神经垂直段。解剖学实践、体会面神经垂直段与接近面神经过程中骨质的改变、颜色改变,才能更准确地定位面神经。     

耳内镜手术相关面神经解剖

目的为安全实施耳内镜手术,避免面神经损伤提供解剖依据。方法对12例2 4侧成人尸头样本进行解剖,暴露面神经全程,对面神经进行相关解剖测量,从外耳道、鼓窦、迷路（乙状窦）后径路用耳内镜对面神经进行观察。结果所有标本均能通过上述径路在耳内镜下完整观察面神经全程,且清晰显露面神经隐窝以及咽鼓管鼓口周围结构。面神经垂直段恰位于骨迷路中轴线位置,面神经水平段介于外半规管和镫骨头之间;面神经鼓室段和上半规管顶、外半规管上缘距离分别为（8.59±1.75）mm和（3.83±1.11）mm,面神经乳突段距后半规管下缘距离为（3.13±1.53）mm;面神经乳突段和外耳道前、后壁距离分别为（10.50±1.91）mm和（3.8 5±0.9 9）mm;鼓索神经出外耳道后壁处和面神经鼓室段之间垂直距离为（2.2 1±0.7 6）mm,鼓索神经和面神经乳突段间夹角为2 7.3 0°±5.9 7°,内耳门外侧距乳突骨质表面水平距离为（33.82±2.80）mm,内耳门上缘距岩骨上缘距离为（4.96±1.40）mm。结论耳内镜可以清晰显示显微镜难以暴露的手术区域,能清晰分辨并避免损伤面神经,在耳显微外科有广阔的应用前景。     

面神经鼓乳段定位及术中面瘫预防

目的:根据颞骨解剖结合中耳手术体会,探讨面神经走行定位,避免中耳手术中面神经损伤.方法:用30侧颞骨标本,模拟面神经减压术的手术步骤暴露面神经鼓乳段,确定面神经走行,用易见且恒定的标志进行面神经定位.结果:面神经水平段位于水平半规管与镫骨之间达匙突前上;垂直段位于鼓室后壁,垂直段后缘延长线与水平半规管后1/3相交,夹角为(117.04±2.42)°,其深度位于水平半规管及鼓环平面以下;外膝位于水平半规管前下方.水平半规管中点至面神经最短距离为(1.97±0.53)mm,砧骨短脚至面神经最短距离为(1.03±0.29)mm,匙突至面神经最短距离为(0.93±0.25)mm,镫骨头至面神经最短距离为(1.18±0.42)mm,前庭窗平面鼓沟至面神经的距离为(3.08±0.28)mm,圆窗平面鼓沟与面神经的距离为(2.13±0.34)mm.结论:水平半规管凸、砧骨短脚、镫骨、鼓环及匙突,是面神经鼓乳段理想的定位标志.熟悉面神经走行,可提高中耳手术安全性.     

面神经隐窝进路相关解剖测量及临床应用

目的:探讨面神经隐窝进路手术的显微解剖,为临床开展相关手术提供解剖学基础。方法:8例(16侧)成人尸头颞骨按照面神经隐窝进路行手术解剖,观察和测量面神经隐窝进路入口、面神经、镫骨头、圆窗、圆窗龛、锥隆起、匙突等解剖结构,将数据进行统计学处理。结果:面神经隐窝进路骨性入口内外宽度为(2.94±0.32)mm,上下高度为(8.83±0.84)mm,深度为(3.51±0.17)mm。镫骨头与面神经水平段的距离为(1.38±0.21)mm,与面神经乳突段的距离为(6.94±0.47)mm,与圆窗的距离为(3.60±0.55)mm,与匙突的距离为(2.23±0.33)mm,与锤骨前韧带的距离为(4.93±0.61)mm。锥隆起与面神经水平段的距离为(1.05±0.09)mm,与面神经乳突段的距离为(5.63±0.41)mm,与圆窗的距离为(3.01±0.34)mm,与圆窗龛的距离为(3.29±0.44)mm,与匙突的距离为(4.13±0.51)mm。圆窗与匙突的距离为(5.11±0.61)mm,与面神经水平段的距离为(3.97±0.61)mm。圆窗龛与面神经水平段的距离为(4.13±0.38)mm,与面神经乳突段的距离为(7.28±0.29)mm。结论:面神经隐窝进路在现代耳显微外科手术中有重要地位,砧骨短脚、镫骨、锥隆起、匙突的解剖位置比较恒定,可作为术中的参考标志。     

Transmastoid exposure of the labyrinthine segment of the facial nerve: an anatomical study

IntroductionCompression of the labyrinthine segment of the facial nerve by edema has been considered as an important pathology in the majority of the cases of idiopathic facial nerve paralysis. Hence, it is suggested that total decompression of the facial nerve should also include the labyrinthine segment by a middle fossa approach. However, the middle fossa approach requires craniotomy and temporal lobe retraction, which increases the morbidity. The labyrinthine segment of the facial nerve can also be reached through mastoidectomy. However, many ear surgeons are not familiar with this approach due to the lack of anatomical data on this surgical area.ObjectiveTo study the anatomical limitations of decompression of the labyrinthine segment via transmastoid approach.MethodsComplete mastoidectomy was performed in six adult cadavers heads. Dissection was extended in the zygomatic root and posterior bony wall of the external auditory canal to visualize the incudomallear joint completely. The bone between tympanic segment, lateral and superior semicircular canal’s ampullas and middle fossa dural plate was removed. Fine dissection was carried out over tympanic segment of the facial nerve in an anterosuperomedial direction the labyrinthine segment was reached.ResultsAll the mastoids were well pneumatized. Distances between the labyrinthine segment and middle fossa dura, and between the labyrinthine segment and superior semicircular canal, were 2.5 and 4.5 mm on average, respectively. In addition, distances between the middle fossa dura and dome of the lateral semicircular canal, and between the middle fossa dura and tympanic segment were 4.6 mm and 4.3 mm on average, respectively.ConclusionIt is possible to expose the labyrinthine segment of the facial nerve through mastoidectomy by dissecting the bone in the area between the tympanic segment of the facial nerve, middle fossa dural plate and ampullary ends of the lateral and superior semicircular canals.     

中耳手术中的面神经定位

目的结合颞骨解剖和面神经手术，明确适用于手术的面神经解剖标志。方法44具颞骨标本面神经解剖，106例周围性面神经麻痹的面神经减压手术。根据面神经周围的固定解剖标志，确定面神经位置。结果①面神经垂直段标志：水平半规管后中1／3交界处垂直线提示面神经后缘；砧骨短角上缘弧度延长线为面神经垂直段前缘；面神经与水平半规管基本在同一深度；②面神经水平段标志：位于砧骨短突之下；在水平半规管隆突前缘向前上呈30。行走；在匙突后方，面神经与匙突平行形成中上鼓室内侧面交界缘；经过匙突面神经向前上行走到膝状神经节；③膝状神经节定位：从镫骨头到匙突等距离延长线为膝状神经节位置；④鼓索神经定位：鼓索从左侧鼓沟的3点或右侧鼓沟的9点出骨管，沿鼓沟向前行走于砧骨长突外侧和锤骨颈内侧；鼓索神经从面神经发出处距离茎乳孔5—8mm；鼓索位于鼓膜紧张部与松弛部交界处。所有手术所见面神经走向符合解剖所见。结论中耳乳突的固定标志是面神经定位的参照物，其中水平半规管的位置最恒定，根据参照物确定面神经位置提高了手术的安全性。     

中耳手术相关面神经管的解剖观测

目的：为避免中耳手术中对面神经的损伤。方法：对２０ 具（４０ 侧）成人尸头颞骨内面神经进行解剖观察。结果：①面神经裂缺率为３２．５％ （１３／４０）,迷路段、水平段、垂直段分别为５％ （２／４０）、２７．５％ （１１／４０）、７．５％ （３／４０）。②面神经垂直段与后半规管最短距离为０．６２～５．０８（２．４８±０．６３）ｍ ｍ ,鼓沟底水平面神经与鼓索神经最短距离为０～４．６２（２．１２±０．７６）ｍ ｍ ,鼓沟底水平面神经与鼓沟最短距离为２．９６～８．８２（５．８６±１．６２）ｍ ｍ 。③面神经水平段与外半规管最短距离为０～３．０２（１．９２±０．８４）ｍ ｍ ,与蹬骨底板最短距离为０．９２～４．０６（２．１４±０．９０）ｍ ｍ 。结论：熟悉颞骨内面神经解剖,可避免对面神经的损伤,减少和避免面瘫的发生     

MSCT多模态三维重建观测颞骨结构及对人工耳蜗手术的指导意义

目的 探讨采用MSCT影像三维多模态重建技术在人工耳蜗植入术术前评估、术后复查中的应用价值.方法 ①应用双阈值重建技术显示耳蜗、前庭、半规管的膜性立体结构及听小骨,颞骨透明成像,逐一融合显示听小骨、内耳与颞骨的关系;②面神经曲面重建显示面神经的走行,观察面神经与面神经隐窝、外耳道后壁、鼓索神经等邻近结构的关系;③双斜径多平面重建(MPR)技术测量鼓岬平面面神经垂直段与鼓索神经的距离.结果 该组83例,内耳畸形11例中Mondini畸形2例、半规管畸形2例、共同腔畸形2例、内听道狭窄1例、前庭导水管扩大4例.正常结构耳鼓岬平面面神经垂直段与鼓索神经距离左侧(0.270±0.057)cm,右侧(0.280±0.068)cm.术后复查5例,清晰显示植入电极位置良好.结论 多模态重建技术能较好地满足临床多角度、全方位观察中耳和内耳解剖的需要,评估手术风险,确保手术顺利进行并可应用于术后复查植入电极的位置.     

High-resolution computed tomography of posterior tympanum

A complex set of sinuses, eminences and ridges lies in the posterior border of the tympanic cavity (posterior tympanum). The facial nerve canal is located between the facial sinus and the sinus tympani. The posterior limit is the posterior semicircular canal. The posterior tympanum is often the site of residual collection of granulation tissue or cholesteatoma, and is not directly visualized by the usual surgical approaches. Thus preoperative knowledge of cholesteatoma in these area is of obvious importance. It has been accepted that high-resolution computed tomography (HRCT) has the significant advantage to provide specific information of the middle ear. Contribution of the HRCT for diagnosis of posterior tympanum was examined by three temporal bone specimens and one hundred subjects with normal middle ear. In the experiments using the temporal bone specimens, each structure in the posterior tympanum was labeled by a fine needle. HRCTs were subsequently obtained to confirm the labeled structure. In one hundred subjects, it was examined whether each structure was also confirmed by the routine HRCT. Results are as follows: (1) Axial HRCT sections provided essential informations for the preoperative evaluation of the posterior tympanum. (2) Such bony structures as the pyramidal eminence and the pyramidal ridge were the most prominent structures on the posterior wall. (3) Laterally close to the pyramidal eminence lies one sinus which was marked by the needle placed in the facial sinus proper or in the lateral tympanic sinus; It is the facial sinus in a wide sense.(ABSTRACT TRUNCATED AT 250 WORDS)     

高分辨CT检查面神经管与周围结构解剖关系

目的探讨高分辨CT（high resolution CT,HRCT）中面神经管与周围结构解剖关系,为进行手术操作提供可靠信息。方法回顾2007年8月～2009年9月我院行颞骨HRCT检查且无颞骨病变的患者118例,其中男性65例,女性53例;在工作站上对轴位及重组出的矢状位、冠状位,观察各段面神经管周围重要结构的距离进行测量,比较不同侧别、性别上述测量值有无差异。结果垂直段前缘距外耳道后壁距离成人为（4 23±0.73）mm,垂直段距乙状窦前壁距离（9.93±2.16）mm,垂直段距蜗窗距离（3.21±0.31）mm,垂直段距鼓岬外缘最短距离（4.32±0.57）mm,砧骨短脚距面神经锥段距离（3.32±0.37）mm,水平段距蜗窗水平距离（2.28±0.48）mm,水平段距鼓岬外缘水平距离（2.23±0.18）mm,面隐窝宽度（5.12±0.31）mm。结论 HRCT是研究面神经管与周围结构影像解剖的优良方法,可为耳显微外科手术中避免面神经的意外伤害提供可靠信息。     

Anatomic variations of the chorda tympani canal

The anatomic variations of the facial recess are of interest in certain otosurgical procedures. The medial border of the recess is the mastoid portion of the facial nerve canal, and the lateral border is the bony canal of the chorda tympani. These two structures were investigated in 64 polyester casts of temporal bone specimens. The point of exit of the chorda tympani canal from the facial canal was assessed together with the angle, formed between these two nerve channels. As a further way of describing the spaciousness at the facial recess, the distance between the sulcus of the stapedius muscle and the chorda tympani canal was evaluated.     

Anatomy of sinus tympani

30 temporal bones from adult cadavers of both sexes were examined. After the tympanic sinus was identified, its morphologic features were evaluated. Minimum distance from adjacent structures: lateral and posterior semicircular canal, facial nerve canal and jugular fossa were taken. Measurements were taken under operative microscope with eye-piece graduation of 0.05 mm accuracy. Four main morphologic types of entrance to the sinus and two main developmental forms--deep and shallow sinus were distinguished. Deep sinus coexisted with absence of bridge and conversely if bridge was seen sinus was shallow. Deep sinuses were located close to the facial canal, in some cases penetrating around the canal up to 2/3 of canal's circumference. This anatomical variation increase the risk of the facial nerve damage during the surgery. In most of cases tympanic sinus is oval in shape. It's long diameter lies in vertical plane. The mean distance between the sinus and adjacent structures were as following: facial nerve canal--1.5 mm, lateral semicircular canal--2.1 mm, posterior semicircular canal--1.59 mm, jugular fossa--5.5 mm. No differences dependent from gender and side were found.     

经耳内镜鼓窦与上鼓室入路人工耳蜗植入的解剖研究

目的 探讨经耳内镜鼓窦、上鼓室自然通道人工耳蜗植入术的可能性.方法 在4例冰冻成人正常颞骨标本开展新手术入路,并测量相关参数,术后中耳高分辨CT加以证实.结果 所有标本均切开鼓窦,经鼓窦入口、上鼓室、中鼓室放置植入电极,在耳内镜下经外耳道鼓室切开显露蜗窗龛,通过蜗窗植入电极,未损伤鼓索神经、面神经.鼓后峡宽度(4.65...     

The posterior ligament of the incus (“white dot”): A reliable surgical landmark for the facial recess

ObjectiveThere is a void in the literature describing reliable surgical landmarks that aid in the dissection of the facial recess in the absence of skeletonizing the mastoid segment of the facial nerve. The posterior ligament of the incus is a readily distinguishable “white dot” along the incus buttress that has been used to guide dissection in a safe and efficient manner. The goal of our study is to describe a surgical approach that utilizes this surgical landmark to drill the facial recess and to take anatomical measurements demonstrating the safety and reliability of this approach.Materials and methodsAfter cortical mastoidectomies were performed in 10 cadaveric temporal bones, the white dot was identified at the junction of short process of the incus and the incus buttress. Using the white dot for anatomical reference, a 2 mm diamond drill bit was used to open the facial recess without first identifying the facial nerve or chorda tympani nerve. After photographs were taken, the facial and chorda tympani nerves were definitively identified and skeletonized to delineate the confines of the facial recess. Photographs were once again acquired in a consistent manner for comparison. Finally, calibrated anatomic measurements were acquired from the 10 distinct image sets.ResultsThe facial recess was successfully drilled in 10 temporal bones using the posterior ligament as a surgical landmark without injury to the chorda tympani or facial nerve. The median angle taken from the axis of the short process of the incus to the facial nerve - chorda tympani junction was 139.2° (IQR 136.8–141). At the widest point in the facial recess, median distances anterior and posterior to an imaginary line connecting the white dot to the facial nerve - chorda tympani junction were 1.6 mm (IQR 1.5–1.7) and 1.6 mm (IQR 1.6–1.7; p = 0.57), indicating at this point, the white dot reference reliably bisects the facial recess width. Similarly, at the level of the round window niche, median anterior and posterior distances from an imaginary line connecting the white dot to the facial nerve - chorda tympani junction were 1.1 mm (IQR 1.1–1.3) and 1.3 mm (IQR 1.1–1.7; p = 0.07), respectively, once again demonstrating the white dot reliably bisecting the facial recess.ConclusionsThe white dot, representing the posterior ligament of the incus, is a reliable surgical landmark that aids in safe and efficient drilling of the facial recess without first skeletonizing the facial nerve.