听小骨的动脉供应

对20例足月新生儿,经颈总动脉注射含墨汁的乳胶液,显示听小骨的动脉。在解剖显微镜下观察到锤骨和砧骨具有滋养动脉和粘膜动脉,而镫骨只由粘膜动脉供应。鼓室前动脉是锤骨和砧骨的主要动脉来源,经岩鼓裂进入鼓室,分为五支——锤骨动脉、砧骨动脉、上支、后支和鼓索支。锤骨动脉为滋养动脉,经锤骨颈部的滋养孔入骨,砧骨动脉经长脚基部的滋养孔入骨。上支和后支为粘膜动脉,供应锤骨头、砧骨体和短脚。锤骨柄由分布于鼓膜上的耳深动脉和茎乳动脉的分支供应。砧骨长脚的粘膜动脉由砧骨动脉的分支、沿鼓索分布的动脉以及来自镫骨方面的动脉供应。镫骨的动脉一是来自面神经管内的动脉,一是来自鼓室岬血管丛。来自后者的有:镫骨头动脉、镫骨后脚动脉和镫骨前脚动脉,前两种动脉过去未曾被提到。面神经管内有茎乳动脉和岩浅动脉,前者发出镫骨肌腱动脉,后者发出残存的镫骨动脉及后脚动脉。关于砧镫关节及砧骨长脚下部的血供,来自镫骨方面的动脉多于砧骨方面的动脉。综上所述,由第一鳃弓软骨发生的锤骨头、砧骨体和短脚主要由鼓室前动脉分布,由第二鳃弓软骨发生的听小骨的其余部分主要由茎乳动脉供应。     

正常中耳腔的CT仿真内窥镜技术

目的：探讨正常听骨链的CT仿真内窥镜(CTVE)成像技术方法及其对中耳结构显示程度。方法：15例无中耳疾病的健康人，层厚1mm、螺距1．0轴位薄层扫描，骨算法、0．1～0．2mm间隔重建，行CTVE成像，观察正常听骨链的情况。结果：采用CTVE技术，对锤骨、砧骨及锤砧关节及砧镫关节的显示率均能清晰的显示，砧镫关节呈“L”形。但镫骨底板和镫骨的前、后脚显示欠佳，约有1／3可以显示。结论：CTVE成像技术能很好地显示中耳腔内部的听骨链立体结构，特别是可以部分显示镫骨底板，该技术将在活体上对中耳腔形态及功能的研究有重要意义。     

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。     

听小骨的形态变异和畸形

我们从120具新生儿尸体中,挑选原套、成对的锤骨200只(100付)、砧骨224只(112付)、镫骨164只(82付),共588只听小骨,在解剖显微镜下观察,发现听小骨在形状、长度、粗细、角度、弯曲等方面的变异颇多。本文介绍了锤骨头前凹、锤骨柄外侧缘的形态、锤骨柄前弯、砧骨长、短脚的形态、镫骨脚和镫骨底的各种形态变异。在240只耳中,发现5例(2.1%)听小骨先天性畸形:先天性镫骨底固定(1例)、环状镫骨与镫骨底分离(1例)、小柱状镫骨(2例)、镫骨与砧骨长脚和锤骨柄间借类骨组织连结(1例)。     

不同激振位置对压电式人工中耳听力补偿性能的影响

研究不同激振位置对压电式人工中耳听力补偿性能的影响,确定压电式人工中耳最优激振位置。建立人耳有限元模型,并通过和相关实验数据进行对比验证模型的可靠性。基于该模型,分别在鼓膜脐部、砧骨体、砧骨长突和圆窗施加相同的位移驱动,通过检测镫骨足底板位移及基底膜的最大位移,分析这些位置的激振对人工中耳听力补偿性能的影响。结果表明,以镫骨足底板位移为评估标准会低估圆窗激振的高频听力补偿效果。砧骨长突激振下的基底膜特征位置处的运动位移大于激振鼓膜脐部及激振砧骨体时的位移值,其中激振砧骨体时的基底膜特征位置处运动位移最小;激振圆窗时的基底膜特征位置处运动位移在低频段小于激振其他位置时对应的位移值,但在中、高频段其激振效果最好。在频率低于400 Hz时,砧骨长突激励听力补偿效果最好,圆窗激励听力补偿效果最差。当频率大于1 kHz时,圆窗激励听力补偿效果比其他位置好。以传统的镫骨足底板响应为评估标准,将低估圆窗激振式人工中耳的听力补偿效果。     

听小骨包埋技术

听小骨体积细小,传统包埋法对其结构细节显示欠佳。作者对该法进行改良,达到较好观察效果。1　听小骨的取材与处理　在固定过的颅底处,打开鼓室盖,小心取出三块完整听小骨,仔细剥除其表面的软组织,经乙醇梯度脱脂,脱水,风干备用。2　听骨链的粘接　采用O-SECOND胶水,先涂一小滴胶水于砧骨的砧锤关节面处,将锤骨按解剖位置与砧骨粘接,固定约5分钟,可使砧锤二骨基本粘牢,再将粘好的砧锤二骨于砧镫关节面上薄薄涂上一层胶水,把镫骨按解剖位置与砧骨粘接,固定约5分钟,即将听骨链完全粘好。注意胶水不可涂太多,太多胶水反而使凝固时间延长,增…     

典型中耳病变对圆窗激振听力补偿性能影响的数值分析

目的研究典型中耳病变对圆窗激振听力补偿效果的影响,为圆窗激振式人工中耳的优化设计提供参考。方法利用CT扫描和逆向成型技术建立包括中耳和耳蜗的有限元模型,并验证模型的可靠性。再基于该模型,通过改变相应组织的材料属性,分别模拟镫骨环韧带硬化、镫骨不正常发育和锤骨前韧带硬化3种典型中耳病变。通过对比相应的基底膜响应,分析这3种病变对圆窗激振听力补偿效果的影响。结果镫骨不正常发育主要在高频处降低圆窗激振的效果,镫骨环韧带硬化和锤骨前韧带硬化主要恶化圆窗激振低频段的响应。3种病变中,镫骨环韧带硬化对圆窗激振听力补偿效果影响较大,等效声压的减小量可高达17 d B。结论中耳病变恶化圆窗激振的听力补偿效果,且恶化量较大,故在设计圆窗激振式人工中耳时需要针对性地提高其作动器的输出量。     

听小骨显微外科解剖学的研究(摘要) Ⅰ、听小骨的形态和畸形

<正> 常规防腐固定的新生儿尸体120具,除1例为无脑儿外,其余外观无畸形。取出完整、成对的锤骨200只,砧骨224只,镫骨164只。每只听小骨均在解剖显微镜下放大10至16倍观察,结果如下。一、听小骨的形态     

基于遗传算法反求耳结构弹性模量

本研究通过力学反问题原理,利用已知的位移求解耳结构弹性模量。随机产生遗传算法的初始种群,使用自编的Matlab算法程序,对初始种群进行遗传迭代计算,把已知的目标位移与种群位移的均方差作为目标函数,以目标函数值最小控制迭代进化的方向。通过耳结构的鼓膜凸和镫骨底板2个控制位移以及砧镫关节周围的8个控制位移这两个算例求解正常砧镫关节的弹性模量,并使用耳结构的鼓膜凸和镫骨底板2个控制位移求解病变砧镫关节的弹性模量。结果表明,使用基于遗传算法的反问题方法计算耳结构的弹性模量是可行的,并且具有稳定性和不受结构力学性能影响的特点,相对误差分别为0.05%和0.2%、0.03%,可为临床病变耳提供有效的力学参数。     

细菌生物膜厚度和面积对人耳听力的影响

依据临床健康志愿者右耳的CT扫描结果,将CT扫描数据数值化导入PATRAN软件进行人耳三维有限元模型的重建,并用NASTRAN软件对该模型进行频率响应分析。通过对正常人耳结构进行频率响应分析得出数据与实验数据吻合,验证了模型的正确性。结合临床中耳炎病症实际情况,研究细菌生物膜的成长阶段对人耳听力的影响。结果表明：在不同声压相同的频率段,细菌生物膜的厚度变化对人耳听力的影响是相同的。在相同声压不同频率段,细菌生物膜的厚度增加会引起镫骨振幅和速度降低,在较低频率段镫骨振幅和速度下降幅度较大,下降的最大值为1.64 dB;在较高频率段镫骨振幅和速度下降幅度较小,下降的最大值为1.04 dB。在不同声压作用下,在相同的频率段细菌生物膜的面积增加会引起镫骨振幅和速度降低。在100～1 000 Hz频率段镫骨振幅和速度的下降幅度较小,下降的最大值为0.18 dB。在1000～10 000 Hz频率段镫骨振幅和速度的下降幅度较大,下降的最大值为2.26 dB。细菌生物膜厚度或面积增加都会使人耳听力下降,厚度增加在低频时比高频时下降更多,而面积增加则刚好相反。     

Joint formation in the middle ear: lessons from the mouse and guinea pig.

The malleus, incus and stapes form an ossicle chain in the mammalian middle ear. These ossicles are articulated by joints that link the chain together. In humans and mice, fusion of the ossicles leads to hearing loss. However, in the adult guinea pig the malleus and incus are normally found as a single complex. In this report, we investigate how the malleus and incus form during mouse and guinea pig development. The murine malleus and incus develop from a single condensation that splits to form the two ossicles. Even before a morphological split, we show that the ossicles have distinct genetic identities and joint markers are expressed. In the guinea pig embryo, joint formation is initiated but no cavitation is observed, resulting in a single complex divided by a thin suture. The malleal-incudo complex in the guinea pig is, therefore, not caused by a defect in joint initiation.     

The expression of tenascin‐C and tenascin‐W in human ossicles

The ossicles of the middle ear (the malleus, incus and stapes) transmit forces resulting from vibrations of the tympanic membrane to the cochlea where they are coded as sound. Hearing loss can result from diseases such as rheumatoid arthritis (RA) that affect the joints between the ossicles or degenerative processes like otosclerosis that lead to ankylosis of the footplate of the stapes in the oval window of the cochlea. In this study, immunohistochemistry was used to determine if the extracellular matrix glycoproteins tenascin‐C or tenascin‐W are expressed in the incudomalleolar and incudostapedial joints of ossicles dissected from human cadavers. Tenascin‐C, which is expressed during inflammatory conditions including RA, was seen in the articular cartilage of the incudomalleolar joints and the head of the stapes. Tenascin‐W, in contrast, was enriched in the annular ligament that anchors the footplate of the stapes into the oval window of the cochlea.     

Ear malformations in the mouse embryo following maternal administration of triazene,with clinical implications

Triazene administration to 10-day pregnant mice gave rise to severe ear abnormalities, including middle ear ossicle malformations. The head of the malleus and the body of the incus were sometimes absent. In some instances, the stapes appeared dysplastic. The stapedial artery was often quite dilated, as well as other cephalic vessels, but qualitatively normal. Severe inner ear abnormalities were observed, as well as auditory nerve disruption, which was associated with central nervous system lesions. Multiple haematomas were present in the embryonic face, but ear abnormalities occurred even in the absence of local hemorhages. We postulate a direct effect of the teratogen on the branchial mesenchyme. This model seems to be useful for the comprehension of human middle ear abnormalities, but does not constitute a phenocopy of hemicranial microsomia.     

Finite element analysis of the effects of a floating mass transducer on the performance of a middle ear implant

Experimental evidence has shown that floating mass transducers (FMTs) play a key role in the performance of middle ear implants. However, because of the tiny size and complex structure of the middle ear, systematic experimental study of the influences of FMTs is difficult to carry out. In this paper we develop a FMT-attached middle-ear finite element model to investigate some effects of a FMT on the performance of a middle ear implant. This model was constructed based on a complete set of computerized tomography section images of a healthy volunteer's left ear. The validity of the developed model was verified by comparing the model-predicted motion of the tympanic membrane and stapes footplate with published experimental data. The result shows that the FMT produces a mass loading effect prominently at high frequencies, the force required to drive the incus to the equivalent of 100 dB sound pressure level (SPL) is about 89?μN, and setting the attachment position of the FMT close to the incudostapedial joint can enhance the driving effect.     

Three-Dimensional Finite Element Modeling of Human Ear for Sound Transmission

An accurate, comprehensive finite element model of the human ear can provide better understanding of sound transmission, and can be used for assessing the influence of diseases on hearing and the treatment of hearing loss. In this study, we proposed a three-dimensional finite element model of the human ear that included the external ear canal, tympanic membrane (eardrum), ossicular bones, middle ear suspensory ligaments/muscles, and middle ear cavity. This model was constructed based on a complete set of histological section images of a left ear temporal bone. The finite element (FE) model of the human ear was validated by comparing model-predicted ossicular movements at the stapes footplate and tympanic membrane with published experimental measurements on human temporal bones. The FE model was employed to predict the effects of eardrum thickness and stiffness, incudostapedial joint material, and cochlear load on acoustic-mechanical transmission through the human ossicular chain. The acoustic-structural coupled FE analysis between the ear canal air column and middle ear ossicles was also conducted and the results revealed that the peak responses of both tympanic membrane and stapes footplate occurred between 3000 and 4000 Hz.     

Micro-CT of the human ossicular chain: Statistical shape modeling and implications for otologic surgery

The ossicular chain is a middle ear structure consisting of the small incus, malleus and stapes bones, which transmit tympanic membrane vibrations caused by sound to the inner ear. Despite being shown to be highly variable in shape, there are very few morphological studies of the ossicles. The objective of this study was to use a large sample of cadaveric ossicles to create a set of three-dimensional models and study their statistical variance. Thirty-three cadaveric temporal bone samples were scanned using micro-computed tomography (μCT) and segmented. Statistical shape models (SSMs) were then made for each ossicle to demonstrate the divergence of morphological features. Results revealed that ossicles were most likely to vary in overall size, but that more specific feature variability was found at the manubrium of the malleus, the long process and lenticular process of the incus, and the crura and footplate of the stapes. By analyzing samples as whole ossicular chains, it was revealed that when fixed at the malleus, changes along the chain resulted in a wide variety of final stapes positions. This is the first known study to create high-quality, three-dimensional SSMs of the human ossicles. This information can be used to guide otological surgical training and planning, inform ossicular prosthesis development, and assist with other ossicular studies and applications by improving automated segmentation algorithms. All models have been made publicly available.