Zhang Xiangming, Gan Rong Z
J Biomech Eng. 2014 Aug;136(8):0810041-7. doi: 10.1115/1.4027668.
Stapedial annular ligament (SAL) is located at the end of human ear ossicular chain and provides a sealed but mobile boundary between the stapes footplate and cochlear fluid. Mechanical properties of the SAL directly affect the acoustic-mechanical transmission of the middle ear and the changes of SAL mechanical properties in diseases (e.g., otosclerosis) may cause severe conductive hearing loss. However, the mechanical properties of SAL have only been reported once in the literature, which were obtained under quasi-static condition (Gan, R. Z., Yang, F., Zhang, X., and Nakmali, D., 2011, "Mechanical Properties of Stapedial Annular Ligament," Med. Eng. Phys., 33, pp. 330-339). Recently, the dynamic properties of human SAL were measured in our lab using dynamic-mechanical analyzer (DMA). The test was conducted at the frequency range from 1 to 40 Hz at three different temperatures: 5 °C, 25 °C, and 37 °C. The frequency-temperature superposition (FTS) principle was applied to extend the testing frequency range to a much higher level. The generalized Maxwell model was employed to describe the constitutive relation of the SAL. The storage shear modulus G' and the loss shear modulus G" were obtained from seven specimens. The mean storage shear modulus was 31.7 kPa at 1 Hz and 61.9 kPa at 3760 Hz. The mean loss shear modulus was 1.1 kPa at 1 Hz and 6.5 kPa at 3760 Hz. The dynamic properties of human SAL obtained in this study provide a better description of the damping behavior of soft tissues than the classic Rayleigh type damping, which was widely used in the published ear models. The data reported in this study contribute to ear biomechanics and will improve the accuracy of finite element (FE) model of the human ear.
镫骨环形韧带（SAL）位于人耳听骨链末端，在镫骨足板与耳蜗内淋巴液之间提供了一个密封但可移动的边界。SAL的力学性能直接影响中耳的声-机械传导，疾病（如耳硬化症）中SAL力学性能的变化可能导致严重的传导性听力损失。然而，SAL的力学性能在文献中仅被报道过一次，且是在准静态条件下获得的（Gan, R. Z., Yang, F., Zhang, X., and Nakmali, D., 2011, “镫骨环形韧带的力学性能”，《医学工程与物理学》，33卷，第330 - 339页）。最近，我们实验室使用动态力学分析仪（DMA）测量了人SAL的动态性能。测试在1至40 Hz的频率范围内、5°C、25°C和37°C三个不同温度下进行。应用频率-温度叠加（FTS）原理将测试频率范围扩展到更高水平。采用广义麦克斯韦模型来描述SAL的本构关系。从七个样本中获得了储能剪切模量G'和损耗剪切模量G"。在1 Hz时平均储能剪切模量为31.7 kPa，在3760 Hz时为61.9 kPa。在1 Hz时平均损耗剪切模量为1.1 kPa，在3760 Hz时为6.5 kPa。本研究中获得的人SAL的动态性能比已发表的耳部模型中广泛使用的经典瑞利型阻尼能更好地描述软组织的阻尼行为。本研究报告的数据有助于耳部生物力学研究，并将提高人耳有限元（FE）模型的准确性。
