Hüttenbrink K B
Hals-Nasen-Ohren-Universitäts-Klinik Münster.
Laryngol Rhinol Otol (Stuttg). 1988 Aug;67(8):404-11.
The still unidentified function of the middle ear muscles might be explained by the fixation theory. However, this idea, which is being favoured nowadays, namely, that the action of the muscles controls the position of the ossicles for optimal transmission, has never been investigated experimentally except for a few studies 50 and 100 years ago. In 25 temporal bone preparations, the air pressure-induced movements of the ossicles were microscopically measured, at first without and then with a 10 g. load on the tensor tympani muscle and a 5 g. load on the m. stapedius. The fixation hypothesis could not be confirmed, since with increasing pressure the movement-reducing effect of the middle ear muscle pull decreased. This inability of the muscles to compensate higher static air pressures is also demonstrated theoretically. A 10 g. pull of the tensor tympani muscle can only withstand a suction of 30 mm H2O in the ear canal. Hence, further evaluations are discussed that seem to enforce our hypothesis of the joint-preserving function of the middle ear muscles. The required antagonism of the pull of the muscle is accomplished by the change of the direction of movement in the gliding incudo-malleal joint.
中耳肌肉仍未明确的功能或许可用固定理论来解释。然而，如今备受青睐的观点，即肌肉的作用是控制听小骨的位置以实现最佳传导，除了50年和100年前的少数研究外，从未经过实验验证。在25个颞骨标本中，先用显微镜测量了听小骨在气压作用下的运动，之后分别在鼓膜张肌上施加10克负荷以及在镫骨肌上施加5克负荷后再次测量。固定假说无法得到证实，因为随着压力增加，中耳肌肉牵拉的运动减弱效应降低。从理论上也证实了肌肉无法补偿更高的静态气压。鼓膜张肌10克的牵拉只能承受外耳道30毫米水柱的吸力。因此，讨论了进一步的评估方法，这些方法似乎强化了我们关于中耳肌肉具有保护关节功能的假说。肌肉牵拉所需的拮抗作用是通过滑动的砧镫关节运动方向的改变来实现的。
