Bluestone Charles D
Department of Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
Laryngoscope. 2008 Mar;118(3):522-7. doi: 10.1097/MLG.0b013e31815ddaa0.
I posit that humans appear to be the only species that develops otitis media. If animals in the wild had developed middle-ear disease to any significant degree, they would have been selected out during evolution because they would not have survived their predators given the associated hearing loss. Why do humans have otitis media? Evolution has had a significant impact. It is well known that humans are born 12 months too early, which is the result of adaptations to bipedalism and our big brain that, over time, resulted in a relatively small female pelvic outlet compared with nonhuman primates. As a consequence of too early a birth, not only is our immune system immature, but the eustachian tube is too short and floppy in the first year of life. But why is otitis media still common in older individuals? What other adaptation is uniquely human? We developed speech that was associated with descent of the larynx and hyoid bone, which, along with a decrease in prognathism (i.e., facial flattening), resulted in a change in palatal morphology as compared with other primates. Comparative anatomic and physiologic studies have demonstrated significant differences between humans and monkeys, especially in the muscles of the eustachian tube. Paradoxic constriction, as apposed to dilation, on swallowing is a common tubal dysfunction in humans and certain monkey models with chronic middle-ear effusion. My hypothesis is that chronic otitis media with effusion in patients with tubal constriction is a consequence of adaptation for speech and that, most likely, the levator veli palatini muscle is the cause.
我认为人类似乎是唯一会患中耳炎的物种。如果野生动物中耳疾病发展到任何显著程度，它们在进化过程中就会被淘汰，因为伴随的听力损失会使它们无法从捕食者口中幸存。为什么人类会患中耳炎呢？进化产生了重大影响。众所周知，人类早产12个月，这是适应双足行走和大脑袋的结果，随着时间推移，与非人类灵长类动物相比，人类女性骨盆出口相对较小。由于出生过早，不仅我们的免疫系统不成熟，而且在生命的第一年，咽鼓管太短且松弛。但为什么中耳炎在老年人中仍然很常见呢？人类还有什么独特的适应性特征呢？我们发展出了与喉部和舌骨下降相关的语言能力，这与颌凸度减小（即面部变平）一起，导致与其他灵长类动物相比，腭部形态发生了变化。比较解剖学和生理学研究表明，人类和猴子之间存在显著差异，尤其是在咽鼓管肌肉方面。吞咽时出现的反常收缩而非扩张，是人类和某些患有慢性中耳积液的猴子模型中常见的咽鼓管功能障碍。我的假设是，咽鼓管狭窄患者的慢性中耳积液性中耳炎是语言适应的结果，而且很可能提腭肌是病因。
