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Anatomy and Physiology of Hearing
Published in R James A England, Eamon Shamil, Rajeev Mathew, Manohar Bance, Pavol Surda, Jemy Jose, Omar Hilmi, Adam J Donne, Scott-Brown's Essential Otorhinolaryngology, 2022
Ananth Vijendren, Peter Valentine
The middle ear acts as an efficient transformer to conduct acoustic energy from the low-impedance high-velocity TM, to the high-impedance, low-velocity fluid-filled cochlea. The impedance difference is mainly matched by the ratio of the surface area of the TM to the stapes footplate (approximately 18:1, or about 25 dB). A much smaller part is played by the lever action of the ossicles. The stapedius muscle plays a role in reflex contraction and stiffening of the ossicular chain to protect the cochlea's sensory epithelium from high-amplitude sounds (see below). In humans, the role of the tensor tympani is unknown, but it does not normally contract in response to sound. Aside from air conduction, the cochlea can also be directly stimulated by vibration of the bony skull (through the bone of the EAC, ossicles or cochlea). The middle ear has a resonant frequency around 1–3 kHz. If this resonance is reduced by a mechanical problem in the ossicular chain (e.g. fixation), the ossicular component of bone conduction is affected and results in a drop in the bone-conduction threshold. This classically appears at 2 kHz as Carhart's notch in the bone-conduction threshold in otosclerosis; however, Carhart's effect may be present between 1 and 4 kHz in any pathology affecting the ossicles.
Head and Neck
Published in Rui Diogo, Drew M. Noden, Christopher M. Smith, Julia Molnar, Julia C. Boughner, Claudia Barrocas, Joana Bruno, Understanding Human Anatomy and Pathology, 2018
Rui Diogo, Drew M. Noden, Christopher M. Smith, Julia Molnar, Julia C. Boughner, Claudia Barrocas, Joana Bruno
The tensor veli palatini is a 1st arch (mandibular) muscle, accordingly innervated by the trigeminal nerve (CN V), but actually lies in the pharyngeal region (Plate 3.36). True to its developmental origin as a muscle attached to part of the cartilage of the 1st arch, it is more superficial (lateral) than true pharyngeal muscles such as the levator veli palatini. In the adult, the tensor veli palatini originates from the scaphoid fossa of the sphenoid bone and wraps around the hamulus of the medial pterygoid plate to attach onto the palatine aponeurosis, and therefore tenses the soft palate when contracted. The tensor tympani, a middle ear muscle attached to the handle of the malleus (also a 1st arch derivative), is also innervated by the trigeminal nerve (CN V) (Plate 3.45). As its name indicates, this muscle tenses the tympanic membrane to dampen loud sounds. Therefore, keep in mind that the two head muscles that have names including “tensor” are both 1st arch (mandibular) muscles, innervated by CN V.
Physiology of Hearing
Published in John C Watkinson, Raymond W Clarke, Christopher P Aldren, Doris-Eva Bamiou, Raymond W Clarke, Richard M Irving, Haytham Kubba, Shakeel R Saeed, Paediatrics, The Ear, Skull Base, 2018
Soumit Dasgupta, Michael Maslin
The tensor tympani supplied by the Vth nerve has very low electrical activity in response to sound. It attaches to the malleus manubrium and pulls the malleus anteriorly. However, it is active in the following situations: tactile stimulation of the EAC and face, pneumatic pressure on the eyelids, sudden forced opening of closed eyelids or forced closing of the eyelids, swallowing, head movements, anticipation of loud sounds and a startle.37 It is interesting that these movements all entail some movement of the bony skull which can stimulate the cochlea. Disorders of the tensor tympani may generate the ‘tensor tympani syndrome’, which manifests as an audible thump in the ear; the condition is rare.37
Central versus marginal tympanic membrane perforations: does it matter? An analysis of 792 patients
Published in Acta Oto-Laryngologica, 2021
Fábio André Selaimen, Leticia Petersen Schmidt Rosito, Mauricio Noschang Lopes Silva, Alice Lang Silva, Valentina de Souza Stanham, Sady Selaimen Costa
As questioned in the title, does it matter? Yes, it matters, since it may directly influence the patients’ treatment and counseling. Additional surgical steps may be necessary if the proposed pathogenesis can be related to the previous retraction. Section of the tensor tympani tendon and fold, employment of more resistant grafts (as cartilage), removal of tympanic remnants over the promontory and posterior recesses, and even a concomitant ventilation tube insertion or other procedures to restore the Eustachian tube function are examples of possible additional steps [20]. It is our belief that a more comprehensive understanding of this process will guide us to a better assessment of three key temporal moments in the treatment protocol: the past (pathogenesis), the present (tailored surgery) and the future (long term prognosis).
First emerging objective experimental evidence of hearing impairment following subarachnoid haemorrhage; Felix culpa, phonophobia, and elucidation of the role of trigeminal ganglion
Published in International Journal of Neuroscience, 2019
Metin Celiker, Ayhan Kanat, Mehmet Dumlu Aydin, Dogukan Ozdemir, Nazan Aydin, Coskun Yolas, Muhammed Calik, Halil Olgun Peker
In our opinion, the vasodilation of the TGG artery can be diminished by a lower neuronal density in the TGG, and this vasospasm cause to lower phonophobia scores in SAH. We showed the degeneration of TGG as a cause of hypoacusia following SAH, The nerve of this ganglion is trigeminal nerve is the principal sensory nerve to the tympanic membrane. The vibration of the eardrum is thought to stimulate the ipsilateral trigeminal nerve, leading to contraction of the tensor tympani muscle [19]. Tensor tympani muscle augments the strain of eardrum and increases in sound severity and facilitate hearing. There is evidence that the tensor tympani muscle and the stapedius muscle, modulate acoustic input by influencing the ossicular chain in rabbits [20]. The stapedius muscle is innervated by the facial nerve. Paralysis of stapedius muscle innervating branch of facial nerve cause hyperacusia [21]. Thus, the attenuation effect of the acoustic stapedius reflex protects the inner ear from acoustic damage. In this study, we first-time demonstrated the protective effect of the tensor tympani following SAH.
Physical therapist guided active intervention of chronic temporomandibular disorder presenting as ear pain: A case report
Published in Physiotherapy Theory and Practice, 2022
Sudarshan Anandkumar, Murugavel Manivasagam
This case report describes the successful physical therapy management of a patient with TMD presenting with left ear pain. The relationship between otological symptoms such as ear ache and TMD have been established (Macedo et al., 2014; Maciel, Landim, and Vasconcelos, 2018) with the incidence reaching up to 85% in patients with TMD (Kusdra et al., 2018). However, the exact mechanism by which this occurs is still unclear (Mejersjö and Näslund, 2016). The facial, masticatory and inner ear muscles (i.e. tensor palate and tensor tympani) have a common embryologic origin, which may allow referred pain from the TMJ into the ear (Stepan, Shaw, and Oue, 2017).