Subarcuate canal and artery: a case report

Variations in the course of the subarcuate artery (SAA) and of its related funnel are infrequent and asymptomatic. We present a case of a 15-year-old girl with a preverbal severe bilateral hearing loss and a subarcuate canal with an unusual course and atypical correlation with the adjacent anatomical structures, particularly with the lateral semicircular canal and the facial nerve. The variation proposed in this case, not previously reported in the literature consulted, can have important implications during middle ear surgical procedures, particularly for the retro-facial tympanoplasty approach: in fact otologic surgeons should consider any kind of variation of the SAA in surgical planning to avoid unexpected hemorrhages. The CT-scan, particularly HRCT, is a very useful tool for the study of intrapetrous vessels and their funnels, and should be considered mandatory in the case of a posterior approach to the tympanic cavity.     

枕下乙状窦后入路内听道后壁磨除的显微解剖

目的 观测经枕下乙状窦后入路手术路径中,显微镜下磨除内听道后壁所涉及的重要解剖结构及相关解剖学参数,以指导术中安全磨除内听道后壁。方法 模拟枕下乙状窦后入路,对6具(12侧)国人湿性头颅标本显微镜下行磨除内听道后壁,以内听道内口后缘中点(P点)作为参照点,分别测量P点至弓状隐窝、后半规管、共脚、内听道底、前庭导水管外口、颈静脉孔的最短距离,对这些结构拍照记录,所得测量结果行统计学处理。结果 以内听道后壁作为参照平面,测得内听道干与后壁平面所呈夹角为47.3°±17.2°。以P点作为参照点,测得P点至弓状隐窝的最短距离(4.10±0.60)mm,P点至后半规管最短距离(7.39±0.44)mm,P点至共脚的最短距离(8.09±0.47)mm,P点至内听道底距离(9.08±0.59)mm,P点至前庭导水管外口(10.44±0.73)mm,P点至颈静脉孔最短距离(7.35±1.09)mm。结论 枕下乙状窦后入路磨除内听道后壁,其磨除长度不应超过7 mm,可减少半规管及共脚的损伤概率。熟悉磨除内听道后壁过程中容易损伤的结构,可避免损伤半规管、颈静脉球、前庭导水管外口及内淋巴囊等重要解剖结构。     

The canal of the posterior ampullar nerve: an important anatomic landmark in the posterior fossa transmeatal approach

Abstract The canal of the posterior ampullar nerve is located between the inferior part of the internal acoustic meatus and ampulla of the posterior semicircular canal. It permits a more accurate localisation of the underlying labyrinth in inner-ear surgery. An anatomical and radiological study was undertaken to determine the importance the relationship between the canal and the labyrinth. Ten dry and 10 cadaveric temporal bone dissections, together with 20 high resolution CT scans of the same temporal bones were studied in an attempt to describe the anatomy of the canal of the posterior ampullar nerve. The length of the canal of the posterior ampullar nerve, the length of internal acoustic meatus, and distances from porus acusticus to the singular foramen and the transverse crest, and from the singular foramen to the vestibule and transverse crest, and from operculum to the sigmoid sinus and to the porus acusticus were measured. During the transmeatal posterior cranial fossa approach using the canal of the posterior ampullar nerve as a landmark enables more bone to be safely removed from the internal acoustic meatus thus preserving hearing.     

The variational anatomy of the external aperture of the human vestibular aqueduct

A study was undertaken to demonstrate the variational anatomy of the external aperture of the vestibular aqueduct in 90 human temporal bones obtained from 58 cadavers. Topographic landmarks of the posterior surface of the petrous bone are useful for general orientation and include the external aperture of the vestibular aqueduct, internal auditory meatus, sigmoid sinus, subarcuate fossa, superior petrosal sinus and cochlear canaliculus. We determined the mean distances from the external aperture of vestibular aqueduct to the above structures to be 10.98, 11.21, 9.42, 10.27 and 13.90 mm, respectively. Furthermore, the length of the external aperture of the vestibular aqueduct revealed significant differences between the right and left sides. The distances between the EAVA and certain anatomical structures on the posterior surface of the temporal bone should be taken into consideration during surgery. Knowing the variability of the position of the external aperture of the vestibular aqueduct may help surgeons avoid traumatizing, and thus producing inadvertent lesions to the hearing mechanism.     

颞骨岩部入路颅底手术有关的应用解剖

目的:为经岩部入路颅底手术提供解剖学参数.方法:观测成人的100例干燥整颅、20例颅底标本、15例尸头及36侧正常颅底CT资料;观测项目为与经岩部入路颅底手术有关的颞骨表面标志与岩部内重要结构的位置及其间距.结果:整颅及颅底内面各项测量结果左右侧比较U均<1.96,P均>0.05,颞骨内重要结构间及与表面标志间距离测量结果多数项目男女性间比较U均>1.96或>2.58,P<0.05或<0.01;颅中窝入路可以弓状隆起作标志寻认上骨半规管以确认内耳道,也可以岩大神经管裂孔为标志暴露面神经膝状神经节与迷路段确认内耳道底;磨除岩尖部骨质时可以颈动脉管后壁与内耳门内侧缘的连线作为界线.结论:颞骨表面标志点间距及颞骨岩部内重要结构间的位置关系可为经岩部入路颅底手术提供重要参考,有利于术中岩部重要结构的定位与保护.     

Transparent model of temporal bone and vestibulocochlear organ made by 3D printing

The vestibulocochlear organ is composed of tiny complex structures embedded in the petrous part of the temporal bone. Landmarks on the temporal bone surface provide the only orientation guide for dissection, but these need to be removed during the course of dissection, making it difficult to grasp the underlying three-dimensional structures, especially for beginners during gross anatomy classes. We report herein an attempt to produce a transparent three-dimensional-printed model of the human ear. En bloc samples of the temporal bone from donated cadavers were subjected to computed tomography (CT) scanning, and on the basis of the data, the surface temporal bone was reconstructed with transparent resin and the vestibulocochlear organ with white resin to create a 1:1.5 scale model. The carotid canal was stuffed with red cotton, and the sigmoid sinus and internal jugular vein were filled with blue clay. In the inner ear, the internal acoustic meatus, cochlea, and semicircular canals were well reconstructed in detail with white resin. The three-dimensional relationships of the semicircular canals, spiral turns of the cochlea, and internal acoustic meatus were well recognizable from every direction through the transparent surface resin. The anterior semicircular canal was obvious immediately beneath the arcuate eminence, and the topographical relationships of the vestibulocochlear organ and adjacent great vessels were easily discernible. We consider that this transparent temporal bone model will be a very useful aid for better understanding of the gross anatomy of the vestibulocochlear organ.     

乙状窦后手术入路的显微解剖和虚拟解剖

目的 探索运用显微解剖和虚拟解剖的方法 研究乙状窦后手术入路,为该入路提供多种方式的形态学基础. 方法 10具(20侧)头颅固定标本,在显微镜下模拟乙状窦后入路手术,观察桥脑小脑三角内结构,并以岩上窦乙状窦汇合处、内耳门为基点进行相关测量;磨除内听道后壁,暴露其内结构;5例患者薄层CT和MRI影像数据,利用Dextroscope系统进行计算机三维重建,虚拟解剖乙状窦后入路手术过程. 结果 岩上窦乙状窦汇合处距三叉神经、面听神经复合体、舌咽神经、舌下神经穿硬膜处的距离分别是(38.50±2.64)mm、(27.80±2.25)mm、(32.70±2.11)mm、(44.30±2.05)mm;内耳门距三叉神经、展神经、小脑幕、舌咽神经穿硬膜处的距离分别是(5.68±1.55)mm、(13.80±1.81)mm、(5.00±0.66)mm、(6.34±1.24)mm.以面听神经复合体和舌咽神经为标志将桥脑小脑三角分为前、中、后3个间隙;在内听道后壁磨除后,该区结构层次充分显示.Dextroscope系统成功模拟乙状窦后手术入路,可显示星点、横窦乙状窦膝、颈静脉孔、内耳门、岩尖、基底动脉系统等结构及其空间关系. 结论 将桥脑小脑三角分为前、中、后3个间隙,有助于了解其内神经血管等结构的层次特点;以岩上窦乙状窦汇合处、内耳门为基点进行测量,可量化结构间的关系,有助于判断各间隙深浅、空间大小;识别内听道内的解剖标志,有利于手术时保护其内结构;通过Dextroscope系统能个体化显示局部结构,方便术前方案的设计.两种方法 各有优缺点,两者互补能提高对乙状窦后入路手术时桥脑小脑三角内结构的认识.     

The location of the obturator nerve: a three-dimensional description of the obturator canal

Satisfactory analgesia cannot be achieved in every obturator nerve block. To attempt to improve the success rate of obturator nerve block, this study describes the detailed anatomy of the obturator region and canal. Eleven (5 female and 6 male) cadavers, totally 22 sides were dissected. Anatomical positions of the structures entering and leaving the canal were defined. The position of the obturator nerve and its branches and their relation with the obturator artery, vein, and with the internal iliac and femoral veins were investigated. A mould of the canal and a model were created. Detailed measurements were performed on the cadavers and models. The obturator canal was in the shape of a funnel compressed from superior to inferior, with anterior and posterior openings. At the entrance of the canal, the nerve lay superiorly; the artery was in the middle, and the vein lay inferiorly. The obturator nerve ran close to the lateral wall of the obturator canal. The distance of lateral wall of obturator canal to the median plane was 41.4 +/- 1.1 mm. After leaving the canal, the nerve lay laterally while the anterior branch of the artery was medial. A venous plexus lay between the two structures. The presence of the branches of the obturator artery and vein alongside the obturator nerve may increase the risk of injury to these structures during anaesthetic procedures. The anterior division of the obturator nerve has a close relationship with these vessels. To provide complete analgesia, the obturator nerve should be blocked in the obturator canal or at its external orifice.     

The appearance of foramen in the internal aspect of the mental region of mandible from Japanese cadavers and dry skulls under macroscopic observation and three-dimensional CT images

The lingual canal with foramen displays different appearances on the internal surfaces of mandible as confirmed by macroscopic observation and computerized tomography (CT). The lingual canal was observed in the inside of mental region run to the outside of lingual foramen, which is extend internally from mandibular canal in right and left sides of the mandible in cadavers (13 sides out of 88 sides) and in dry skulls (43 out of 94 sides) examined. The spinal foramen connected with mental canal occurred at the midline of mandible in 6 cases (6 out of 47 cases) in dry skulls. In this small foramen, the inferior alveolar artery give some branches to the inside of mental region at the anterior mandible and which may be run pass through the lingual canal to the lingual foramen, where they emerge to enter the mylohyoid or anterior belly of digastric muscles. The observations of these are important considerations for surgical placement of dental implants in the region in the mandible.     

迷路后桥脑小脑三角区内镜手术的应用解剖研究

目的：评价内镜在桥脑小脑三角区手术中的应用价值。方法：对5例10侧成人尸头进行大体解剖，熟悉桥脑小脑三角区诸结构解剖关系；在10例20侧成人尸头上模拟迷路后径路内镜手术，将镜下结构按解剖位置分为面神经、三又神经、舌咽神经三个区域，重点观察各区域各组颅神经之间、神经和血管之间关系；在15例标本上，于颞骨岩部后骨板平面测量内耳门外缘距后半规管外缘、颞骨表面距离，内耳门下缘距舌咽神经距离。结果：10例标本通过内压小脑均能成功导入内镜进行模拟手术；内耳门及第7、8颅神经可作为内镜手术的解剖标志。内耳门外缘距颞骨表面距离为（33．82±2．80）mm，距后半规管后缘距离为（13．24±2．55）mm，下缘距舌咽神经距离为（6．26±1．05）mm。结论：迷路后径路桥小脑角区内镜手术完全可行，较显微镜手术而言具有微创、能多角度观察病变区域、更清晰分辨血管神经关系等优点，更适合耳科医生采用，但需熟悉和掌握有关解剖知识以及内镜操作技巧。     

A clinico-anatomic study of the auricular branch of the vagus nerve and Arnold’s ear-cough reflex

Summary The results of a clinico-anatomic study of the auricular branch of the vagus nerve (ABVN) and Arnold's ear-cough reflex are presented. The frequency of the ear-cough reflex was found to be 2.3% (12 out of 514 patients). It was bilateral in 3 cases (0.6%). The reflex was elicited by palpation of the postero-inferior wall of the external acoustic meatus (EAM) in 11 patients, and by palpation of the antero-inferior wall in one patient (0.2%). The reflex was frequently noticed to occur after a short latent period. The course of the ABVN inside the jugular foramen (JF), and distribution of the terminal branches of the ABVN in the external acoustic meatus were determined in 8 male cadavers (16 sides). In addition, the length of the mastoid canaliculus (MC) and the relationships of the ABVN with the facial nerve and stylomastoid foramen (SMF) were studied in both cadavers and 25 dry skulls (50 sides). High-resolution computed tomography (HRCT) scanning was also performed in all cadavers prior to microdissections. The ABVN emerged from the superior ganglion of the vagus nerve in all the cadavers. It ran between the internal jugular vein (IJV) and the bony wall of the jugular foramen. The ABVN was encased in a partial bony canal during its course from the jugular foramen to mastoid canaliculus in 18% of all specimens. The average length of the mastoid canaliculus was 5.6 mm (4.2–6.5), and it ran transversely towards the tympanomastoid suture 4.5 mm (4–5.1) above the stylomastoid foramen. The mastoid canaliculus was well demonstrated in all the HRCT scans.

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Etude anatomo-clinique de la branche auriculaire du nerf vague et du réflexe de toux otogène d'Arnold

Résumé Les résultats d'une étude anatomo-clinique concernant la branche auriculaire du nerf vague (BANV) et le réflexe de toux otogène d'Arnold sont exposés. Un réflexe de toux otogène a été trouvé dans 2,3 % des cas (12 cas sur 514). Il était bilatéral dans 3 cas (0,6 %). Le réflexe a été provoqué par la palpation de la paroi postéro-inférieure du méat acoustique externe dans 11 cas. Il a été provoqué après la palpation de sa paroi antéro-inférieure dans 1 cas (0,2 %). Il faut noter que le réflexe est souvent apparu après une brève période de latence. Le trajet de la BANV à l'intérieur du foramen jugulaire et la distribution des branches terminales de la BANV dans le méat acoustique externe ont été précisés sur 8 sujets mâles (16 côtés). De plus, la longueur du canalicule mastoïdien, les rapports de la BANV avec le nerf facial et le foramen stylo-mastoïdien ont été étudiés à la fois sur des sujets anatomiques et sur 25 crânes secs (50 côtés). Une tomodensitométrie à haute résolution a également été réalisée sur tous les sujets anatomiques avant les microdissections. La BANV émergeait du ganglion supérieur du nerf vague sur tous les sujets. Elle passait entre la veine jugulaire interne et le canal osseux du foramen jugulaire. La BANV était enchâssée dans un canal osseux partiel durant son trajet depuis le foramen jugulaire jusqu'au canalicule mastoïdien dans 18 % des cas. La longueur moyenne du canalicule mastoïdien était de 5,6 mm (4,2 – 6,5), et il se dirigeait transversalement vers la suture tympano-mastoïdienne à 4,5 mm (4 – 5,1) au-dessus du foramen stylomastoïdien. Le canalicule mastoïdien a été bien mis en évidence sur toutes les tomodensitométries.

     

正常人面神经管垂直部与外耳道解剖位置关系的影像与临床研究

目的 观察、测量面神经管垂直部毗邻解剖关系及乳突的形态学指标,分析面神经管垂直部和外耳道后壁、外耳门后缘位置变化的相关性,探讨乳突气化程度与面神经管垂直部之间的关系及临床意义。 方法 1. 评价CT影像测量相关结构的正确性,采用64层螺旋CT对4具干颅标本进行扫描,在横断位测量面神经管垂直部至外耳道后壁、外耳门后缘的距离,在矢状平面上测量乳突的前后径（外耳道下壁最低点至乳突后缘的水平距离）和高度（外耳道下壁至乳突尖的垂直距离）;按影像层面锯开标本,对上述距离行实体测量。影像测量均值与实体测量均值的差异行显著性检验。2. 在体研究：随机入选无耳部疾患的118人（236侧）,其中男性55例（110侧）,女性63例（126侧）,行颌面部CT扫描。如上选择层面,并测量面神经管垂直部至外耳道后壁、外耳门后缘及乳突前后径和高度的距离,以乳突前后径与高度乘积的1/2定义为乳突面积,以乳突面积的大小来定义乳突气化程度,同时将乳突面积分别与面神经管垂直部至外耳道后壁、外耳门后缘距离分别进行相关和回归分析。 结果 1. 标本部分：各项指标的影像测量值与实体测量值差异无统计学意义（P>0.05）。2. 在体研究：各项指标测量结果侧别差异无统计学意义（P>0.05）,性别差异有统计学意义（P<0.05）。乳突面积与面神经管垂直部至外耳道后壁距离之间呈负相关性,且相关性有统计学意义;乳突面积与面神经管垂直部至外耳门后缘有相关性,但相关性无统计学意义。 结论 乳突发育气化好,面神经垂直部位置偏前。 CT检查可以明确面神经管垂直部与外耳道后壁的关系,有助于耳外科手术术式的选择以及对术中重要结构损伤的控制。     

Morphology of the middle rectal arteries

The middle rectal arteries were studied in 30 cadavers of adult and older individuals (29 Caucasians and one Negro) of both sexes (15 males and 15 females). The middle rectal artery was present in 56.7% of the cases, bilaterally (36.7%) or unilaterally (20%), originating from the internal pudendal (40%), inferior gluteal (26.7%), internal iliac (16.8%), and less frequently from other pelvic branches. The average external diameter of the middle rectal artery was found to be 1.7 mm, its average length about 7 cm, and the point of penetration in the rectal wall about 6 cm (average) superior to the anus. The most frequent sites of the rectal wall pierced by the middle rectal arteries were the anterior (50% of the cases) and posterior (45%) quadrants of the rectum, whether isolated or combined (43.3%). These anatomical features justify, when needed and possible, the preservation of the middle rectal artery in surgical interventions on related organs. The term middle rectal arteries in Nomina Anatomica should be changed to inferior rectal arteries and indented under internal pudendal artery; the current term inferior rectal arteries should be changed to anal arteries to follow the already adopted division of the terminal intestine into rectum and anal canal.     

蝶窦的CT与断层解剖比较研究

目的：为有关蝶窦手术提供解剖学和影像学资料。方法：采用CT技术和断层解剖方法对15例尸头和50例颅骨标本蝶窦的形态、类型、径线、毗邻等进行了观察。结果：蝶窦的前后径大于上下径，上壁和前壁较苤，下壁和后壁较厚。在蝶窦CT水平层面上可清楚显示其气化类型，前、后壁，两侧壁及中隔的位置、厚度、毗邻；在冠状层面上可显示上、下壁的厚度及上壁与垂体、颈内动脉的关系。蝶窦内可见管型视神经管隆起和管型颈内动脉隆起，其出现率分别为23.8％和21.9％。视神经管隆起仅见于发育良好的鞍前型和全鞍型蝶窦。发育良好的枕鞍型和全鞍型蝶窦的后壁较薄，最苤者仅为0.6mm。结论：蝶窦的气化程度差异较大，视神经、颈内动脉可向窦腔内突入。发育良好的枕鞍型和全鞍型蝶窦与脑干间仅隔以纸样薄骨板。经蝶窦入路手术，应控制手术操作范围，避免损伤毗邻结构。     

The so-called foramen singulare in cetacean periotics is actually the superior vestibular area

It is nearly 100 years ago that the “foramen singulare” was first identified in cetacean periotics. Since then, the “foramen singulare” has been recognized in periotics of many cetacean species, extant or extinct. Surprisingly, however, it has never been confirmed if the foramen singulare in cetacean periotics is really homologous to that in other mammals. It is known that in mammals including humans the posterior ampullary nerve, which innervates the posterior semicircular duct, passes through the foramen singulare. We use an X-ray micro-CT scan to examine endocasts of the bony labyrinth of the inner ear of cetacean periotics, showing that the osseous canal extending from the so-called foramen singulare goes toward the anterior bony ampulla, meaning that the alleged foramen singulare in cetacean periotics is really the superior vestibular area, through which the utriculoampullary nerve enters. The transverse crest is quite significant to identify each quadrant of the fundus of the internal acoustic meatus, but in many cetacean species the transverse crest is poorly developed, almost imperceptible in some species, and this could have brought confusion into the interpretation over the superior vestibular area and the foramen singulare. The bony septum separating the cerebral aperture of the facial canal from the foramen singulare is not the transverse crest, but the perpendicular crest. The foramen singulare is not a distinct foramen separated from the inferior vestibular area. Instead, the true foramen singulare opens near the inferior vestibular area in the internal acoustic meatus in cetacean periotics.     

经颞骨入路手术避免面神经垂直部损伤的相关解剖学数据测量

目的：通过对相关解剖结构的影像观察、测量,探讨经颞骨入路手术中如何避免损伤面神经垂直部。方法：采用16层螺旋cT对68人（136侧）,其中女性33例（66侧）,男性35例（70侧）行颌面部轴位CT扫描。在横断位分别测量面神经管垂直部至外耳道后壁（D1）、外耳门后缘（D2）、乙状窦沟前壁（D3）、颈静脉窝（D4）的水平距离,以及外耳道后壁至乙状窦沟前壁之间水平距离（D5）。结果：D1～D15分别为：（2．87±0．47）mm,（11．09±2．30）mm,（7．95±2．15）mm,（5．45±2．32）mm,（13．48±2．19）mm。面神经垂直部至颈静脉窝之间水平距离左右两侧间差异有统计学意义（P〈0．05）,性别之间差异无统计学意义（P〉0．05）;其余各项指标测量结果侧别差异无统计学意义（P〉0．05）,性别差异有统计学意义（P〈0．05）。结论：通过断层影像解剖学观测,获得了经颞骨入路手术相关结构的解剖学数据,该组数据可为术中避免面神经等重要结构的损伤提供参考。     

What is the arcuate eminence?

A study was made of 100 homogeneous CT scans of the petrous part of the temporal bone to determine whether or not the arcuate eminence (AE) is a good landmark for the superior semicircular canal (SSCC) in the suprapetrous approach to the internal acoustic meatus which is used in the extirpation of acoustic neuromas. Direct measurements were made on consecutive coronal sections, 1 mm thick. The AE was absent from the petrous surface in 15% of cases. It corresponded to the relief of the SSCC in 37% of cases; laterally, however, it was separated from the petrous cortex by bone whose thickness varied from 0.5 to 5 mm. Finally, in 48% of cases, the AE was not a good landmark for the canal although nonetheless it participated in the development of this bulge in 46% of cases, always lying towards the medial border of the pneumatized eminence. In addition, study of the coronal sections with MRI allowed us to confirm that the AE does not routinely correspond to the imprint of a temporal sulcus. The AE, whose presence on the petrous surface is due to the combined effects of the SSCC, the air cells of the petrous part of the temporal bone and the temporal sulci, is only a good guide to the SSCC in 37% of cases and should not be considered as a reliable surgical landmark.     

Three-dimensional imaging of the petrous bone for the middle fossa approach to the internal acoustic meatus: an experimental study

The goal of this study was to highlight the feasibility of creating three-dimensional (3D) pictures of the petrous bone from a routine CT examination which can be used for a middle fossa approach to the internal acoustic meatus, in order to secure this operation. The surgical aim is to reach the roof of the internal acoustic meatus directly without injuring the adjacent functional structures of the petrous bone. Two heads of embalmed cadavers were scanned every millimeter with a slice thickness of 1 mm centered on the petrous bones. The horizontal reference was the Frankfurt line and the frontal and sagittal planes were perpendicular to this line. This method is similar to routine examinations for surgical patients. The pictures were first loaded on an optical disk, then into a computer (Silicon Graphics System). Amira software was used to create 3D pictures. The anatomy of the temporal bone could easily be identified, notably the surgical landmarks of the middle fossa approach. Three-dimensional computer-assisted imaging can reveal the anatomy of the petrous bone in a realistic view. The main anatomic structures for a middle fossa approach can be recognized easily. This realistic view may be very useful for surgeons, and 3D images deserve to be developed further.     

视神经管显微解剖学研究

目的　为视神经管减压术提供解剖学依据。方法　利用解剖学方法对 10 0个颅骨和 6 7个尸头视神经管口及四壁的结构与毗邻进行了观察和测量。结果　视神经管由蝶骨小翼两根与喋骨体构成 ,管自后内向前外斜行 ,分内、外、上、下四壁和颅、眶两口。其上壁、下壁、内侧壁、外侧壁的长度分别为 10 70±0 2 3mm ,6 2 5± 0 18mm ,9 6 7± 0 18mm ,7 91± 0 17mm。内侧壁向筛窦、蝶窦内突入形成视神经管隆凸。视神经在颅口处有硬脑膜压迹 ,视神经腹侧有眼动脉形成的压迹。结论　视神经管隆凸可作为确定视神经管位置的解剖标志。视神经管下壁和内侧壁与视神经、眼动脉、颈内动脉等结构毗邻 ,切除管壁时应注意保护邻近结构。     

内耳道底骨性结构、前庭神经与单孔神经骨管的Micro-CT影像解剖学实验研究

目的 探讨内耳道底骨性结构及前庭神经、单孔神经骨管（神经管）的Micro-CT影像解剖学特征。方法 取10%甲醛溶液固定的成人尸头标本6具（颞骨12侧）,其中男性4具、女性2具,具体年龄不详。对12侧颞骨均行Micro-CT扫描,再应用Mimics软件对内耳道底骨性结构及其中的神经管进行三维重建,之后进行影像解剖学观察,并分别测量前庭上神经、前庭下神经、单孔神经管相关解剖学参数。结果 经Micro-CT扫描及三维重建,内耳道底骨性结构及其内穿行的前庭神经和单孔神经管显示清晰。前庭上、下神经及单孔神经的解剖形态、位置及走行存在多种解剖变异以及多交叉分布现象。左右两侧前庭上神经管长度分别为（3.68±0.79）mm和（3.54±1.04）mm,起始处前后径分别为（2.03±0.76）mm和（1.83±0.68）mm、上下径分别为（1.75±0.35）mm和（1.72±0.43）mm,中点处的前后径分别为（0.89±0.19）mm和（1.13±0.29）mm、上下径分别为（1.58±0.26）mm和（1.69±0.58）mm;左右两侧前庭下神经管前后径分别为（0.44±0.07）mm和（0.50±0.29）mm,上下径分别为（0.53±0.11）mm和（0.76±0.38）mm。左右两侧单孔神经管直线长度分别为（3.97±0.68）mm和（3.85±0.69）mm,其内侧段长度分别为（2.54±0.70）mm和（2.26±0.82）mm、外侧段长度分别为（1.82±0.57）mm和（1.99±0.39）mm,内侧段直径分别为（0.67±0.10）mm和（0.66±0.09）mm、外侧段直径分别为（0.47±0.04）mm和（0.51±0.10）mm,内外段交角分别为128.82°±17.23°和127.51°±11.70°。以上各指标测量值侧别间比较,差异均无统计学意义（P值均>0.05）。结论 Micro-CT扫描及三维重建可清晰显示内耳道底骨性结构及前庭神经、单孔神经骨管等结构及其空间位置与走行;前庭神经和单孔神经骨管解剖形态及位置、走行均存在较大变异,但左右侧别间相关解剖学测量结果无差异。