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Acoustic Criteria
Published in Randall F. Barron, Industrial Noise Control and Acoustics, 2002
The human ear is one of the more intricate and complex mechanical structures in the body. As shown in Fig. 6-1, the ear consists of three main parts: The outer ear, consisting of the pinna or visible ear, which acts as a horn to collect sound, and the meatus or auditory canal, which is terminated by the tympanic membrane or eardrum.The middle ear, which involves three small bones: the malleus or “hammer”, the incus or “anvil,” and the stapes or “stirrup”. These bones of the middle ear serve to transform the pressure variations in the air in the outer ear into mechanical motion. The eustachian tube in the middle ear serves to equalize the pressure between the outer and inner ear volumes.The inner ear, which contains the semicircular canals, the fluid gyroscope associated with maintaining balance of the body, and the cochlea, which analyzes, converts, and transmits information about sound from the outer ear to the brain through the auditory nerves.
Hearing, Proprioception, and the Chemical Senses
Published in Robert W. Proctor, Van Zandt Trisha, Human Factors in Simple and Complex Systems, 2018
Robert W. Proctor, Van Zandt Trisha
The middle ear is connected to the throat by the Eustachian tube. This tube maintains the air pressure within the middle ear at the level of the outside atmospheric pressure, which is necessary for the middle ear system to function properly. Discomfort and difficulty in hearing are often experienced when a plane changes altitude, because the air pressure of the middle ear has yet to adjust to the new atmospheric pressure. Yawning opens the Eustachian tubes and allows the pressure to equalize. If you have ever had to use ear drops, you were probably able to taste the medicine in the back of your mouth after putting them in. This happens when small amounts of the medicine permeate the eardrum and filter through the Eustachian tube.
How we hear
Published in Karl H.E. Kroemer, Fitting the Human, 2017
The Eustachian tube connects the middle ear to the pharynx (part of our breathing apparatus). When the tube is open, it allows the air pressure in the middle ear to remain equal to the external air pressure. But when the tube is obstructed, such as in the case of a cold or an ear infection, pressure equalization may not function, and one feels pressure in the ear, even pain, and cannot hear well. In an airplane, especially during rapid descent, a clogged Eustachian tube can delay the equalization of pressure between the inner ear and the environs. You may try to open the tube by chewing gum or by willful excessive yawning, but “pumping” your outer ear with the hand will not help your middle ear.
3D printing technology and applied materials in eardrum regeneration
Published in Journal of Biomaterials Science, Polymer Edition, 2023
Haolei Hu, Jianwei Chen, Shuo Li, Tao Xu, Yi Li
Currently clinically used autologous materials mainly include temporal muscle fascia, adipose tissue, tragus cartilage, perichendrium, mastoid TM, etc. [18–20]. Currently, the temporal muscle fascia is the most commonly used graft with good efficacy, and it has good flexibility and can be attached to the perforated edge of the TM. However, research indicates that there is, temporal myofascial as cartilage—perichondrium in cases of eustachian tube dysfunction, adhesive otitis media, and perforation [21] Autologous fat is one of the commonly used implants to repair TMs in recent years. Reports using adipose tissue in TM perforation repair indicates a success rate between 76–100%. Adipose tissue is easy to obtain with low adverse reactions, and the success rate is no different from that of the temporal muscle fascia [22]. In addition, fat grafts secrete angiogenesis and growth factors that promote neovascularization and tissue repair, thereby increasing blood supply around the perforation of the eardrum [23]. The chondroperichondrium complex is recommended as a graft material for complex perforations, such as complete and sub-complete perforations, adherent otitis media, recurrent perforations, and eustachian tube dysfunction （Table 2）.