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

1)用狗的颞骨制作砧骨关节脱位、关节和砧骨固定，用He-Ne激光全息干涉法进行分析。2)砧骨关节脱位：与鼓膜的正常振动相比，在250~2 kHz的频率范围内，振动模式没有改变，在3 kHz或更高的频率下，振动模式发生改变。鼓膜振动幅度在2 kHz或更高时增大，而在3 kHz或更高时减小。当砧骨与砧骨关节断裂时，锤骨和砧骨向外移位，即鼓膜由正常位置向外移位。在此条件下，鼓膜硬度下降，共振频率向低频方向移动。由于鼓室体积的增大，共振频率也向低频方向移动，这与僵硬的影响相比可以忽略不计。3)砧骨关节和砧骨的固定：在250 Hz到2 kHz的频率范围内，也有同样的趋势，但在3 kHz以上有变化，节段数减少。鼓膜振动幅度在5 kHz或更高时增大，4 kHz或更低时减小。在听骨链和距骨固定的情况下，听骨链和鼓膜不会像脱位时那样移位，但中耳振动系统中只有硬骨增加。因此，共振频率向高频方向移动。

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.