Vibration analysis of the tympanic membrane with ossicular chain abnormalities by holography

1)以犬颞骨为材料，制备犬臼趾关节脱位及关节与镫骨固定，采用He-Ne激光全息干涉法进行分析。2)包括镫骨关节脱位：与鼓膜正常振动相比，在250 Hz ~ 2 KHz频率范围内的振动模式没有变化；变化发生在3千赫或更高的频率。在2 KHz或损失时，鼓膜振动振幅增大，而在3 KHz或更高时，鼓膜振动振幅减小。当砧骨和镫骨之间的关节断裂时，锤骨和砧骨向外移位，即鼓膜从正常位置向外移位。在这种情况下，鼓膜的刚度下降，共振频率向低频范围偏移。由于鼓室体积的增加，共振频率也会向低频范围内移动，与刚度的影响相比，可以忽略这一点。3)钩突关节与镫骨的固定：在250 Hz至2 KHz的频率范围内，观察到相同的趋势，但在超过3 KHz时发生变化，节段数量减少。鼓膜振动振幅在5khz或更高时增大，在4khz或更低时减小。听骨链与镫骨固定后，未见脱位时听骨链或鼓膜的移位，仅中耳振动系统的硬筋增加。因此，谐振频率向高频范围偏移。

1) Dislocation of the incudostapedial joint and fixation of the joint and the stapes were prepared using the temporal bones of dogs, and an analysis was performed by the holography interference method using a He-Ne laser.2) Dislocation of the incudostapedial joint : in a comparison with the normal vibration of the tympanic membrane, there were no changes in the pattern of the vibrations in the frequency range from 250 Hz to 2 KHz; changes occurred at 3 KHz or higher. The vibration amplitude of the tympanic membrane increased at 2 KHz or loss, but decreased at 3 KHz or higher. When joint between the incus and stapes was broken, the malleus and incus were displaced toward the exterior, i.e., the tympanic membrane was displaced toward the exterior from the normal position. under this condition, it appeared that the stiffness of the tympanic membrane decreased, and the resonance frequency shifted to the low frequency range. The resonance frequency also shifts to the low frequency range due to an increase in the volume of the tympanic cavity, this can be disregarded compared with the effect in stiffness.3) Fixation of the incudostapedial joint and the stapes : In the frequency range 250 Hz to 2 KHz, the same tendency was seen, but there was a change at over 3 KHz, and there was a decrease in the number of segmentations. the vibration amplitude of the tympanic membrane increased at 5 KHz or higher and decreased at 4 KHz or less. With fixation of the ossicular chain and the stapes, there was no displacement of the ossicular chain or the tympanic membrane as in the case of dislocation, but only the stiffners increased in the middle ear vibration system. Therefore, the resonance frequency shifted to the high frequency range.