内耳骨迷路的磨制与雕刻

内耳骨迷路埋藏在颞骨岩部内 ,其形态不规则 ,方位不规范 ,示教较为困难。我们用干骨磨制和湿骨雕刻的方法 ,制作了一些内耳骨迷路的标本。由于标本真实 ,立体感强 ,用于课堂教学后 ,效果好。现将内耳骨迷路的干骨磨制和湿骨雕刻的方法步骤介绍如下。1　干骨内耳骨迷路的磨制1.1　材料　选用骨质较好的完整颞骨、用双氧水漂白 ,以增加标本的美观感。1.2　器械　牙科钻、各型号钻头。1.3　磨制方法　磨制时 ,参照内耳模型 ,按骨半规管、前庭和耳蜗的顺序进行。1.3.1　前骨半规管的磨制　先将颞骨岩部弓状隆起表面的骨质磨掉 ,一次不要去的太…     

多排螺旋CT低剂量扫描高分辨率重建在新型冠状病毒肺炎筛查中的应用

目的:探讨多排螺旋CT（MDCT）低剂量扫描高分辨率重建在新型冠状病毒肺炎（COVID-19）筛查中的应用价值。方法:选取2020年2月1日~3月1日间就诊的66例疑似COVID-19肺炎患者作为研究对象,将66例患者随机平均分为2组,分别实施胸部常规剂量CT扫描（n=33, 120 kV, 300 mAs）和胸部低剂量CT扫描（n=33,100 kV,70 mAs）,其中常规剂量组采用512×512矩阵,低剂量组采用1 024×1 024矩阵。同时对胸部低剂量组用4种不同权重的迭代算法进行处理（30%、50%、70%、90%）,对比两种检查模式的辐射剂量和图像质量。结果:低剂量组的有效辐射剂量为（1.81±0.14） mSV,与常规剂量组（6.83±0.68） mSV相比降低73.5%（P<0.05）;采用1 024大矩阵、90%权重迭代算法的低剂量组图像的CNR、SNR均略低于采用512常规矩阵、90%权重迭代算法的常规剂量组,但差异无统计学意义（SNR:5.11±0.75 vs 5.38±0.41,CNR:5.37±0.33 vs 5.44±0.51, P>0.05）;低剂量组患者的肺窗、纵膈窗图像质量主观评分低于常规剂量组,但差异无统计学意义（肺窗:3.30±0.72 vs 3.39±0.78;纵膈窗:3.15±0.90 vs 3.36±0.82, P>0.05）。结论:使用MDCT进行胸部低剂量扫描,同时采用高分辨率重建技术及90%权重迭代算法可用于COVID-19肺炎筛查,可在保证图像质量的前提下显著降低患者所受辐射剂量。     

成人颞骨骨迷路的解剖学研究及其临床意义

目的:对成人颞骨骨迷路进行解剖观察和测量,为临床提供解剖学基础。方法:制作26侧成人颞骨骨迷路标本进行观察和测量。结果:(1)半规管长度以后半规管最长,前半规管次之,外半规管最短。(2)半规管横断面呈椭圆形,其弓顶处管腔纵径大于横径。(3)壶腹端、单脚端、总脚端均近似圆形。后、前、外半规管壶腹端的纵径分别为:1.94mm,1.95mm,1.92mm。外半规管单脚端纵径为1.20mm,前、后半规管总脚端纵径为1.60mm。(4)三个半规管弓除外半规管弓在同一平面上外,前、后半规管弓均不在同一平面上,而呈不同程度的扭曲。(5)同侧三半规管之间并非相互垂直。(6)26侧中前半规管位于弓状隆突下的有16侧(61.54％),余10侧(38.46％)与弓状隆突不相重叠。结论:本研究结果为骨迷路结构研究增添了新的内容,为临床内耳手术的开展提供解削学基础和参考数据。     

颞骨CT内面神经、迷路、听骨结构深度学习的自动化分割方法

目的 探讨神经网络的深度学习方法,进行颞骨CT内面神经、迷路及听骨结构的自动化分割的可行性和精确性。方法 选择常规颞骨CT检查患者的数据,随机分为两组,一组为训练集（20例）,另一组为测试集（5例）。在上述颞骨CT中采用手工分割的方法,分割出迷路、听骨及面神经结构。选择三维卷积神经网络3D U-Net作为深度学习中的神经网络结构部分,通过对训练集的训练,得到该网络的平均精度。用该网络模型对5组测试集中的不同解剖标志自动分割的结果与手工分割的结果进行测试,分别获得面神经、迷路及听小骨的测试精度。并将上述精度与另一种基于三维卷积神经网络结构的V-Net网络模型获得的精度进行比较。结果 在颞骨CT标本中,采用面神经、迷路及听小骨分别对3D U-Net-plus和V-Net网络结构的自动分割进行训练,在训练样本中,3D U-Net-plus网络结构的平均误差为0.016,V-Net网络结构的平均误差为0.035,两者差异有统计学意义（P<0.05）;利用3D U-Net-plus神经网络自动分割的迷路、听小骨及面神经与手工分割图像的Dice相似指数分别为0.618±0.107、0.584±0.089和0.313±0.069, 利用V-Net神经网络自动分割的迷路、听小骨、面神经与手工分割图像的Dice相似指数分别为0.322±0.089、0.176±0.100和0.128± 0.077,两者差异有统计学意义（P<0.001）。结论 采用3D U-Net-plus神经网络,在颞骨内听骨、迷路及面神经的自动识别和分割方面具有可行性,该方法优于V-Net神经网络。随着网络结构的优化和学习样本的扩大,其将更加接近人工分割的效果。     

颞骨的解剖学标本制作和体会

目的探讨成人颞骨标本的制作方法。方法选用经防腐固定、结构完整的成人头颅标本12具。分别经乳突及颅内颞骨岩部逐层解剖,经乳突后鼓室入路,行乳突切除,依次暴露鼓膜、听骨链、前庭阶和鼓阶。经颅内颞骨岩部逐步磨除颞骨骨质,暴露蜗螺旋管底圈、半规管及附近结构。结果通过本方法制作出了听骨链、鼓室、耳蜗底转及半规管标本。结论:通过以上方法制作的颞骨标本结构完整连续性好,在耳鼻咽喉头颈外科研究生的教学中该标本有助于认识与理解颞骨内复杂结构。     

迷路后径路内镜下行脑桥小脑三角区手术的解剖学研究

目的 :为临床上保留迷路在内镜下行桥脑小脑三角区病变手术提供解剖学资料。方法 :在 2 0例 40侧成人尸头上模拟颞骨径路保留迷路内镜手术 ,测量乙状窦内侧至总骨脚、岩上窦下缘至外半规管在岩部后骨板延长线之间距离 ,对可操作范围进行评估 ,对内镜的导入角度进行研究。并就如何避免损伤半规管、颈静脉球、面神经、乙状窦、岩上窦等结构提出看法。结果 :岩上窦下缘至内淋巴囊上缘距离为(9 .5 3± 2 .64 )mm ,乙状窦内侧至总骨脚距离为 (13 .89± 2 .3 4)mm ,至内淋巴管距离为 (10 .62± 2 .0 9)mm ;由该三条线构成的上底为 13 .89mm ,下底为 10 .62mm ,高为 9.5 3mm的梯形为内镜操作范围。乙状窦距颞骨表面距离 (以乙状窦上膝为标准 )为 (5 .2 7± 1.60 )mm ,乙状窦宽度为 (11.97± 2 .10 )mm ,上下膝长度为 (2 4.78± 4.2 1)mm ,乙状窦与外耳道后壁距离为 (13 .5 9± 3 .0 3 )mm ,岩骨后骨板至后半规管后缘、总骨脚后缘距离分别为 (4 .0 7± 1.2 6)mm和 (5 .5 8± 1.49)mm ,内镜的导入角度应力争与岩部上嵴平行 ,这样的角度最便于观察和操作 ,且不易损伤内部重要结构。我们测得的岩部上嵴与矢状线之间角度为 (63 .87± 9.3 1)°。结论 :保留迷路所得到的操作范围完全可以满足在内镜下行脑桥小脑三角区     

α-氰基丙烯酸正丁酯黏合剂预防经皮椎体后凸成形术中骨水泥渗漏的效果

目的 探讨α-氰基丙烯酸正丁酯（NBCA）黏合剂预防经皮椎体后凸成形术（PKP）中骨水泥渗漏的效果。方法 选用80枚离体猪胸腰椎,经脱钙、力学机压缩椎体制作骨质疏松性椎体压缩骨折模型,按照随机数表法分为常规PKP组和胶水组,每组40枚;再根据骨水泥注射量的不同细分为高剂量组和低剂量组,每组20枚。常规PKP组采用传统手术方法行PKP,胶水组在骨水泥注入前先用自行设计的椎体裂隙喷涂工具进行NBCA预处理封闭椎体内裂隙,再注入骨水泥。统计椎体内骨水泥分布形态、骨水泥渗漏率和椎体骨水泥渗漏数量。结果 胶水组和常规PKP组脱钙后骨密度在高剂量组和低剂量组组间及组内比较,差异均无统计学意义（P>0.05）。胶水组和常规PKP组高剂量骨水泥注射弥散效果均优于低剂量骨水泥注射（P<0.05）,但是组间弥散效果等级比较,差异无统计学意义（P>0.05）。胶水低剂量组骨水泥渗漏率低于常规PKP低剂量组（P<0.05）,胶水高剂量组骨水泥渗漏率低于常规PKP高剂量组（P<0.05）。结论 NBCA黏合剂预处理椎体不影响骨水泥在椎体内的弥散分布,能有效降低PKP术中骨水泥渗漏率...     

多层螺旋CT低剂量扫描在小儿胸部的应用探讨

目的:评价小儿胸部多层螺旋CT低剂量与常规剂量扫描的图像质量,探讨低剂量扫描在小儿胸部应用的可行性.材料与方法:(1)随机选择肺部感染的患儿30例,先常规剂量(150mAs)扫描,再在感染灶局部加作低剂量扫描,剂量为50,35及15mAs.其他参数为:120kV,床进28.8mm/圈,0.5s/圈,16×1.5mm准直,重建层厚及间隔均为3mm.分别记录不同剂量扫描时的CT权重剂量指数(CTDIw)及剂量长度乘积(DLP).(2)由2位高年资医师按优、良、合格及不合格的等级盲法评价不同剂量的图像质量,结果进行统计学处理.结果:(1)小儿胸部35mAs和15mAs的CTDIw与常规剂量150mAs的比值分别为23.0%及10.0%,其DLP与常规剂量比值为23.3%和10.0%.(2)图像质量评价结果:150,50,35,15mAs的可诊断图像χ2检验,肺窗P>0.05 ,纵膈窗P<0.05,提示上述剂量肺窗图像差异无显著性意义,纵膈窗图像差异有显著性意义.用150,50,35mAs的可诊断图像进行χ2检验, P>0.05,提示其差异亦无显著性意义.结论:多层螺旋CT低剂量扫描适用于小儿胸部检查,在保证图像质量的前提下,采用35mAs左右的扫描条件较为适宜.     

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。     

听小骨空间结构相关形态学研究

目的　探讨听小骨在鼓室内相对空间位置结构,为听小骨的空间定位提供数据,为听骨链重建术提供相关解剖学依据。 方法　10%福尔马林固定的完整成年男性头颅20个(40例),解剖并测量锤骨柄长轴、锤骨头颈长轴、砧骨长突、镫骨长轴分别与水平面、矢状面夹角,锤骨柄与锤骨头颈长轴夹角、锤砧关节夹角及砧骨与镫骨间夹角。 结果　锤骨柄长轴与水平面、矢状面夹角分别为（44.89±11.66）°、（41.92±11.68）°,锤骨头颈长轴与水平面、矢状面夹角分别为（41.94±11.14）°、（39.48±10.11）°,砧骨长突与水平面、矢状面夹角分别为（43.50±11.27）°、（35.84±12.39）°,镫骨长轴分别与水平面、矢状面夹角为（25.93±10.39）°、（58.19±8.19）°,锤骨柄与锤骨头颈长轴夹角 (140.93±10.43)°、锤砧关节夹角(96.19±　13.82)°、砧骨与镫骨间夹角(104.27±9.22)°。 结论　听骨链在鼓室内的空间排列呈斜体“N”型。     

基于磁共振数据的三维半规管建模空间方向测量

目的测量半规管相互夹角和空间方向。方法对16例磁共振3D-CISS序列内耳检查影像,分割半规管结构建立三维模型,生成3D PDF文件,在各半规管取3点坐标,通过数学方法对同侧和双侧的半规管相互夹角以及各半规管和水平面的夹角进行计算。结果左右后半规管夹角为98.49°±12.07°,可以推测后半规管和矢状面的夹角为49.25°±6.04°。左右水平半规管夹角为171.58°±3.78°;左侧后半规管和右侧前半规管夹角为165.56°±5.78°,右侧后半规管和左侧前半规管夹角为164.74°±6.46°,左侧水平半规管和水平面夹角为19.43°±3.02°,右侧水平半规管和水平面夹角22.11°±4.12°。结论左右共同平面对半规管近乎平行,后半规管和矢状面的夹角大于45°,两侧半规管总脚分叉点和眼球下缘平面更加接近水平面。     

DAN directs endolymphatic sac and duct outgrowth in the avian inner ear.

Bone morphogenetic proteins (BMPs) are expressed in the developing vertebrate inner ear and participate in inner ear axial patterning and the development of its sensory epithelium. BMP antagonists, such as noggin, chordin, gremlin, cerberus, and DAN (differential screening-selected gene aberrative in neuroblastoma) inhibit BMP activity and establish morphogenetic gradients during the patterning of many developing tissues and organs. In this study, the role of the BMP antagonist DAN in inner ear development was investigated. DAN-expressing cell pellets were implanted into the otocyst and the periotic mesenchyme to determine the effects of exogenous DAN on otic development. Similar to the effects on the inner ear seen after exposure of otocysts to the BMP4 antagonist noggin, semicircular canals were truncated or eliminated based upon the site of pellet implantation. Unique to the DAN implantations, however, were effects on the developing endolymphatic duct and sac. In DAN-treated inner ears, endolymphatic ducts and sacs were merged with the crus or grew into the superior semicircular canal. Both the canal and endolymphatic duct and sac effects were rescued by joint implantation of BMP4-expressing cells. Electroporation of DAN antisense morpholinos into the epithelium of stage 15-17 otocysts, blocking DAN protein synthesis, resulted in enlarged endolymphatic ducts and sacs as well as smaller semicircular canals in some cases. Taken together, these data suggest a role for DAN both in helping to regulate BMP activity spatially and temporally and in patterning and partitioning of the medial otic tissue between the endolymphatic duct/sac and medially derived inner ear structures.     

后半规管非平面性对夹角测量的影响

目的 测量后半规管夹角,观察后半规管非平面性对夹角测量的影响。 方法 对20例磁共振三维稳态构成干预序列内耳检查影像进行分析,通过使用3D Slicer 4.4软件直接测量左、右后半规管的夹角来推算后半规管和矢状面的夹角。 结果 左、右后半规管夹角为90.5°±8.9°,最小夹角73°,最大夹角108°。可推算后半规管和矢状面夹角为45.3°±4.4°,最小36.5°,最大54°。 结论 后半规管切面经过或不经过共脚,由此导致夹角测量差异约为9°,故此次测量数据和既往研究相符,但本方法更加直观方便。     

Ontogenetic Variation in the Bony Labyrinth of Monodelphis domestica (Mammalia: Marsupialia) Following Ossification of the Inner Ear Cavities

Ontogeny, or the development of an individual from conception to death, is a major source of variation in vertebrate morphology. All anatomical systems are affected by ontogeny, and knowledge of the ontogenetic history of these systems is important to understand when formulating biological interpretations of evolutionary history and physiology. The present study is focused on how variation affects the bony labyrinth across a growth series of an extant mammal after ossification of the inner ear chambers. Digital endocasts of the bony labyrinth were constructed using CT data across an ontogenetic sequence of Monodelphis domestica, an important experimental animal. Various aspects of the labyrinth were measured, including angles between the semicircular canals, number of turns of the cochlea, volumes of inner ear constituents, as well as linear dimensions of semicircular canals. There is a strong correlation between skull length and age, but from 27 days after birth onward, there is no correlation with age among most of the inner ear measurements. Exceptions are the height of the arc of the lateral semicircular canal, the angular deviation of the lateral canal from planarity, the length of the slender portion of the posterior semicircular canal, and the length of the canaliculus cochleae. Adult dimensions of several of the inner ear structures, such as the arcs of the semicircular canals, are achieved before the inner ear is functional, and the non‐ontogenetic variation in the bony labyrinth serves as an important source for behavioral, physiological, and possibly phylogenetic information. Anat Rec, 2010. © 2010 Wiley‐Liss, Inc.     

体质量指数指导Z轴自动管电流调制技术在胸部CT扫描中应用价值

目的评价体质量指数（BMI）指导下降低Z轴自动管电流调制技术最大毫安值在胸部CT扫描中的图像质量和辐射剂量,降低辐射剂量应用价值。方法连续选取100例BMI正常同时胸部CT定位像扫描显示无明显异常的受检者,随机分2组,每组50例。低剂量组,男性30例,女性20例,年龄18～75岁,中位年龄为39.74岁;对照组,男性30例,女性20例,年龄18～75岁,中位年龄为41.8岁。2组均使用Z轴自动管电流调制技术,Z轴自动管电流设置范围低剂量组30～200mA,对照组30～350mA。记录CT扫描后机显示容积CT剂量指数（CTDIvol）和剂量长度乘积（DLP）,计算有效剂量（ED）。取每例患者肺尖部、主动弓部、肺底部3幅图像,共计300幅。由2名副主任医师采用5分制双盲法评判,测量相应部位的噪声。所有数据记录录入Excel,分析采用SPSS13.0。结果低剂量组和对照组的图像质量主观评判均符合临床诊断要求。低剂量组的图像噪声肺尖部为12.27±2.64,主动弓部为10.83±2.03,肺底部为13.67±2.98。对照组图像噪声肺尖部10.96±2.42,主动脉弓部为9.71±2.72,肺底部为11.17±2.06。低剂量组噪声值高于对照组,两组比较,差异有统计学意义（P〈0.05）。低剂量组平均CTDIvol、ED分别为（5.89±1.63）mGy、（3.26±0.92）mSv,对照组平均CTDIvol、ED分别为（8.07±2.13）mGy、（4.47±1.20）mSv。结论BMI指导下降低Z轴自动管电流调制技术最大毫安值在胸部CT扫描中既能保证图像满足诊断要求,又大幅降低了受检者辐射剂量。     

基于Matlab精确测量半规管在颅底中的方位

目的:确定半规管在颅底的精确方位,并分析其在不同年龄组、侧别和性别中的差异.方法:将45例正常人(90侧耳)的CT序列图像导入Mimics软件,读取确定半规管平面的标志点以及为确定以法兰克福平面为基准的标准空间坐标系的关键结构标志点的三维坐标,基于Matlab软件编制计算程序Laby Calculation,确定标准空间坐标系的相关方程,计算半规管在标准坐标系中的空间方位和面面夹角,最后对数据进行统计分析.结果:半规管的方位在不同年龄组和性别中具有一定的差异,而左右侧无明显差异,不同年龄组同侧半规管间面面夹角比较差异均无统计学意义(p＞0.05),提示随年龄增长同侧三个半规管方位的旋转可能是作为一个整体一同发生的.结论:本研究可为半规管发育研究提供形态数据,并对相关前庭功能检查和平衡功能障碍治疗提供依据和帮助.     

A Morphometric Study of the Semicircular Canals Using Micro‐CT Images in Three‐Dimensional Reconstruction

It is generally accepted that the three semicircular canals are set at right angles to each other and the lateral semicircular canal is smaller than the anterior and posterior semicircular canals. Precise knowledge of the size and spatial relationships of the semicircular canals is vital, and so the 40 petrous parts of the temporal bones were scanned by micro‐CT at a slice thickness of 35 µm. The micro‐CT images were used in reconstructing three‐dimensional models of the bony labyrinth using computer software. Various dimensions of the semicircular canals were measured using the software, and statistical analysis was performed. The anterior semicircular canal was slightly wider than the posterior semicircular canal, and their heights were similar. The radius of curvature of the lateral semicircular canal was 20% smaller than those of the anterior and posterior semicircular canals. The angles between the three canals were not exactly 90 degrees: they were 92.1, 84.4, and 86.2 degrees between the anterior and posterior, anterior and lateral, and posterior and lateral semicircular canals, respectively. We obtained high‐resolution images of the semicircular canals using three‐dimensional reconstruction software, and these were used to precisely measure the angles between the semicircular canals and the area of the distorted circle formed by each semicircular canal. Anat Rec, 296:834–839, 2013. © 2013 Wiley Periodicals, Inc.     

小儿头部CT扫描中mAs变化对辐射剂量的影响

目的探讨小儿头部CT扫描方案中mAs变化对辐射剂量的影响及临床应用价值。方法选择120例需做头部扫描患儿＋其中男性78例,女性42例．年龄1个月．16岁。小儿头部扫描参数按CT机预设的分为3个年龄组：（曲～1．5岁年龄组（40例）,采用150mAs;②1．5～6．0岁年龄组（40例）,采用200mAs;③6．0～16．0岁年龄组（40例）,采用250mAs。其他扫描技术参数不变．120kV,6mm×3mm准直器组合,6mm层厚。记录扫描时的剂量参数CT剂量加权指数（CTDI。）和剂量长度乘积（DLP）。结果3组CTDI。分别为（21．296±0．586）、（27．990±0．723）、（35．665±0．766）mGy（F=4264．944,P〈0．001）。3组DLP值分别为（242．617±24．277）、（356．262±34．147）、（458．743±20．993）mGy·om（F：638．654,P〈0．001）。扫描参数每降低50mAs,CTDI。降低约22．72％,DLP降低约27．12％;若降低100mAs,CTDI。降低约40．29％,DLP降低约47．11％。结论降低mAs值,可使CT辐射剂量明显降低;在小儿头颅CT检查中,依患儿年龄合理降低mAs值．可以作为CT技师实施儿童放射防护的基本办法．     

Spatial orientation of semicircular canals and afferent sensitivity vectors in pigeons

Rotational head motion in vertebrates is detected by the semicircular canal system, whose innervating primary afferent fibers carry information about movement in specific head planes. The semicircular canals have been qualitatively examined over a number of years, and the canal planes have been quantitatively characterized in several animal species. The present study first determined the geometric relationship between individual semicircular canals and between the canals and the stereotactic head planes in pigeons. Stereotactic measurements of multiple points along the circumference of the bony canals were taken, and the measured points fitted with a three-dimensional planar surface. Direction normals to the plane's surface were calculated and used to define angles between semicircular canal pairs. Because of the unusual shape of the anterior semicircular canals in pigeons, two planes, a major and a minor, were fitted to the canal's course. Calculated angle values for all canals indicated that the horizontal and posterior semicircular canals are nearly orthogonal, but the anterior canals have substantial deviations from orthogonality with other canal planes. Next, the responses of the afferent fibers that innervate each of the semicircular canals to 0.5 Hz sinusoidal rotation about an earth-vertical axis were obtained. The head orientation relative to the rotation axis was systematically varied so that directions of maximum sensitivity for each canal afferent could be determined. These sensitivity vectors were then compared with the canal plane direction normals. The afferents that innervated specific semicircular canals formed homogeneous clusters of sensitivity vectors in different head planes. The horizontal and posterior afferents had average sensitivity vectors that were largely coincident with the innervated canal plane direction normals. Anterior canal afferents, however, appeared to synthesize contributions from the major and minor plane components of the bony canal structure to produce a resultant sensitivity vector that was positioned between the canal planes. Calculated angles between the average canal afferent sensitivity vectors revealed that direction orthogonality is preserved at the afferent signal level, even though deviations from canal plane orthogonality exist.