scholarly journals Anatomy and Development of the Mammalian External Auditory Canal: Implications for Understanding Canal Disease and Deformity

2021 ◽  
Vol 8 ◽  
Author(s):  
Mona Mozaffari ◽  
Robert Nash ◽  
Abigail S. Tucker
Keyword(s):  
Tympanic Membrane ◽  
External Auditory Meatus ◽  
Integrated System ◽  
Sound Waves ◽  
Ear Canal ◽  
Multi Stage ◽  
Anatomical Adaptations ◽  
Clinical Questions ◽  
Canal Atresia ◽  
Conductive Hearing

The mammalian ear is made up of three parts (the outer, middle, and inner ear), which work together to transmit sound waves into neuronal signals perceived by our auditory cortex as sound. This review focuses on the often-neglected outer ear, specifically the external auditory meatus (EAM), or ear canal. Within our complex hearing pathway, the ear canal is responsible for funneling sound waves toward the tympanic membrane (ear drum) and into the middle ear, and as such is a physical link between the tympanic membrane and the outside world. Unique anatomical adaptations, such as its migrating epithelium and cerumen glands, equip the ear canal for its function as both a conduit and a cul-de-sac. Defects in development, or later blockages in the canal, lead to congenital or acquired conductive hearing loss. Recent studies have built on decades-old knowledge of ear canal development and suggest a novel multi-stage, complex and integrated system of development, helping to explain the mechanisms underlying congenital canal atresia and stenosis. Here we review our current understanding of ear canal development; how this biological lumen is made; what determines its location; and how its structure is maintained throughout life. Together this knowledge allows clinical questions to be approached from a developmental biology perspective.

scholarly journals Epithelial dynamics shed light on the mechanisms underlying ear canal defects

Development ◽  
2020 ◽  
Vol 147 (23) ◽  
pp. dev194654 ◽  
Author(s):  
Juan M. Fons ◽  
Mona Mozaffari ◽  
Dean Malik ◽  
Abigail R. Marshall ◽  
Steve Connor ◽  
...  
Keyword(s):  
Explant Culture ◽  
Mutant Mice ◽  
Sound Waves ◽  
Ear Canal ◽  
Primary Canal ◽  
Complex Processes ◽  
Underlying Causes ◽  
Canal Atresia ◽  
First Time ◽  
Periderm Formation

ABSTRACTDefects in ear canal development can cause severe hearing loss as sound waves fail to reach the middle ear. Here, we reveal new mechanisms that control human canal development and highlight for the first time the complex system of canal closure and reopening. These processes can be perturbed in mutant mice and in explant culture, mimicking the defects associated with canal atresia. The more superficial part of the canal forms from an open primary canal that closes and then reopens. In contrast, the deeper part of the canal forms from an extending solid meatal plate that opens later. Closure and fusion of the primary canal was linked to loss of periderm, with failure in periderm formation in Grhl3 mutant mice associated with premature closure of the canal. Conversely, inhibition of cell death in the periderm resulted in an arrest of closure. Once closed, re-opening of the canal occurred in a wave, triggered by terminal differentiation of the epithelium. Understanding these complex processes involved in canal development sheds light on the underlying causes of canal atresia.

scholarly journals Kanaloplasti pada Atresia Liang Telinga Pasca Trauma

2014 ◽  
Vol 3 (2) ◽  
Author(s):  
Jacky Munilson ◽  
Yan Edward ◽  
Surya Azani
Keyword(s):  
Hearing Loss ◽  
Skin Flap ◽  
Rare Condition ◽  
Tissue Formation ◽  
Ear Canal ◽  
Fibrotic Tissue ◽  
Hearing Function ◽  
Post Traumatic ◽  
Canal Atresia ◽  
Conductive Hearing

AbstrakPendahuluan: Atresia liang telinga didapat adalah suatu kelainan yang jarang terjadi dengan karakteristik pembentukan jaringan fibrosis pada liang telinga. Trauma pada liang telinga pada cedera kepala dapat menyebabkan atresia liang telinga pasca trauma dan menyebabkan tuli konduktif serta terbentuknya kolesteatom di daerah cul de sac sehingga diperlukan tatalaksana dengan pembedahan. Ada beberapa pendekatan teknik pembedahan kanoplasti yaitu dengan pendekatan transkanal, endaural dan postaurikula. Metode: Satu kasus atresia liang telinga didapat pasca trauma yang ditatalaksana dengan kanaloplasti transkanal dan bagian tulang yang terpapar ditutupi dengan flap kulit liang telinga. Hasil : Penyembuhan pasca operasi sangat memuaskan, liang telinga lapang dengan perbaikan fungsi pendengaran. Diskusi : Atresia liang telinga didapat salah satunya dapat disebakan oleh trauma dan dapat menimbulkan penurunan pendengaran. Pembedahan pada atresia liang telinga membutuhkan teknik yang khusus karena rekurensi dapat terjadi. Pembedahan dengan pendekatan transkanal sudah dapat memberikan akses yang adekuat. Bagian tulang liang telinga yang terpapar dapat ditutupi dengan flap ataupun graft kulit dengan vaskularisasi yang adekuat serta diperlukannya pembersihan liang telinga pasca operasi secara cermat dan teratur untuk mencegah rekurensi.Kata kunci: Atresia liang telinga, trauma telinga, kanaloplasti transkanal.AbstractIntroduction : Acquired ear canal atresia is a rare condition that characteristic by fibrotic tissue formation in ear canal. Trauma to the ear canal in head injury can cause post traumatic ear canal atresia with conductive hearing loss and cholesteatom in cul de sac area, so this condition necessary surgery procedure. There are several approaches of canaloplasty that are transcanal, endaural and postauricula approach canaloplasty. Methode : One case of post traumatic ear canal atresia that treated with transcanal approach canaloplasty and ear canal skin flap for closing the exposed bone. Result : satisfactory postoperative ear canal healing, with improvement of hearing function. Discussion: Acquired ear canal can be caused by trauma and can cause hearing loss. Surgery on the ear canal atresia requires special techniques because recurrence may occur. Transkanal surgical approach has been able to provide adequate access. The expose bone of ear canal after fibrotic tissue was removed, can be covered by skin flap or skin graft with adequate vascularity as well as the need for postoperative cleaning of the ear canal thoroughly and regularly to prevent recurrence.Keywords: Ear canal atresia, ear trauma, transcanal canaloplasty.

Hearing Disorders

1993 ◽  
Vol 14 (2) ◽  
pp. 43-49
Author(s):  
Isabelle Rapin
Keyword(s):  
Hearing Loss ◽  
Decisive Role ◽  
Minor Role ◽  
Growing Up ◽  
Sound Waves ◽  
Hearing Disorders ◽  
Perceptual Disorders ◽  
A Minor ◽  
Human Attributes ◽  
Conductive Hearing

Definition Hearing is the usual channel for acquisition of this most important of human attributes, language. Language enables humans to communicate at a distance and across time and has played a decisive role in the development of society and its many cultures. Language is the major channel through which children learn about what is not immediately evident, and it plays a central role in thinking and cognition. Because speech is the chief vehicle for communication in all families (except those in which the parents are deaf), deafness is a profound handicap whose effects greatly transcend the inability to speak. Responsibility for detecting hearing loss in infancy rests on the primary physician, inasmuch as early diagnosis and appropriate habilitation will prevent the most serious consequences of infantile hearing loss: growing up without language. Two primary types of hearing loss are attributable to disease of the ear: conductive hearing loss, a deficiency in the transduction of energy in the form of sound waves in air to hydraulic waves in the inner ear; and sensorineural hearing loss, inadequate transduction of these waves to neural activity. Other disorders of hearing include cortical hearing impairment and perceptual disorders. Although much is said about perceptual disorders by educators, such disorders probably play a minor role in the genesis of learning disabilities and will not be addressed in this review, which focuses on severe-to-profound hearing losses.

Acute labyrinthitis and meningitis of the ear origin

1930 ◽  
Vol 26 (9) ◽  
pp. 941-941
Author(s):  
B. Goland
Keyword(s):  
Foreign Body ◽  
Tympanic Membrane ◽  
Foreign Bodies ◽  
Family Doctor ◽  
Ear Canal ◽  
Deep Wound ◽  
The Right

Abstracts. Otorhinolaryngology. Prof. Uffenrode (D. med. Woch. 1929. No. 25.) describes 2 very interesting cases from his practice. 1. To remove peas from the ears of a 5-year-old child, a family doctor used tweezers. In view of the child's strong anxiety, chlorine ethyl anesthesia was applied, but the removal of foreign bodies from the ears was not possible; deep wound in the right ear canal. Secondary chlorine - ethyl anesthesia; the foreign body was removed from the left ear by washing, from the right ear it was not possible. The next day, an otorhinolaryngologist will remove the foreign body from the right ear; a wound of the tympanic membrane was established.

scholarly journals Antero-inferior tympanic visibility during microscopy

2020 ◽  
Vol 6 (9) ◽  
pp. 1714
Author(s):  
Manish Munjal ◽  
Gopika Talwar ◽  
Shubham Munjal ◽  
Tulika Saggar
Keyword(s):  
Tympanic Membrane ◽  
Adult Population ◽  
Neck Surgery ◽  
Ear Canal ◽  
Medical College ◽  
Zero Degree ◽  
Entire Margin ◽  
Perforated Tympanic Membrane ◽  
Inferior Quadrant ◽  
Nose And Throat

<p class="abstract"><strong>Background:</strong> The antero-inferior recess of the ear canal is not visible to the otologist, thereby effecting proper placement of the graft and thereby affecting its uptake .The visibility of this region in the adult population is assessed.</p><p class="abstract"><strong>Methods:</strong> The quadrants of tympanic membrane were examined in 60 subjects with perforated tympanic membrane undergoing tympanoplasty. The study was conducted in the department of ENT-HNS (ear, nose and throat-head and neck surgery), Dayanand Medical College and Hospital, Ludhiana.  </p><p class="abstract"><strong>Results:</strong> With the microscope in 48 (80%) entire perforation could be visualized and in 12 (20%) margins were not in the line of view. 5 perforations were posterior superior and 12 were total perforations. Otoendoscope examination with zero degree could show the entire margin of the perforation.</p><p class="abstract"><strong>Conclusions:</strong> In 80% population the antero-inferior quadrant of the tympanic membrane is accessible to straight vision of the microscope.</p>

Integrated Systems for Cogeneration and Absorption Chilling: Comparison for Varying Chiller COPs

1999 ◽  
Author(s):  
R. Tang ◽  
M. A. Rosen
Keyword(s):  
Steam Turbine ◽  
Integrated System ◽  
Coefficient Of Performance ◽  
Integrated Systems ◽  
Base Case ◽  
Cooling Load ◽  
Absorption Chillers ◽  
Multi Stage ◽  
Wide Range ◽  
Thermodynamic Effects

Abstract The thermodynamic effects are demonstrated of integrating steam turbine-based cogeneration systems with absorption chillers. A wide range of realistic extraction steam pressures and coefficient of performance (COP) values of absorption chillers are considered. A simple model of a steam turbine-based cogeneration plant is used for the evaluation of the integrated system. The integrated systems are evaluated based on the ratio of fuel consumption between a base case (one-stage absorption chiller with a COP value of 0.6) and several alternative cases (multi-stage absorption chillers with COP values ranging from 0.6 to 1.5). Two categories of scenarios are considered: (i) cases where the cooling load is fixed; and (ii) cases where the cooling load is fixed and the electrical output for the integrated system is set equal to that for the base case.

scholarly journals Macroscopic description of the external and middle ear of paca (Cuniculus paca Linnaeus, 1766)

2015 ◽  
Vol 35 (6) ◽  
pp. 583-589 ◽  
Author(s):  
Leandro L. Martins ◽  
Ijanete Almeida-Silva ◽  
Maria Rossato ◽  
Adriana A.B. Murashima ◽  
Miguel A. Hyppolito ◽  
...  
Keyword(s):  
Tympanic Membrane ◽  
Middle Ear ◽  
Gross Anatomy ◽  
Experimental Models ◽  
Temporal Region ◽  
External Ear ◽  
Wild Animals ◽  
Ear Canal ◽  
Macroscopic Description ◽  
Mouse Ear

Abstract: Paca (Cuniculus paca), one of the largest rodents of the Brazilian fauna, has inherent characteristics of its species which can conribute as a new option for animal experimantation. As there is a growing demand for suitable experimental models in audiologic and otologic surgical research, the gross anatomy and ultrastructural ear of this rodent have been analyzed and described in detail. Fifteen adult pacas from the Wild Animals Sector herd of Faculdade de Ciências Agrárias e Veterinárias, Unesp-Jaboticabal, were used in this study. After anesthesia and euthanasia, we evaluated the entire composition of the external ear, registering and ddescribing the details; the temporal region was often dissected for a better view and detailing of the tympanic bulla which was removed and opened to expose the ear structures analyzed mascroscopically and ultrastructurally. The ear pinna has a triangular and concave shape with irregular ridges and sharp apex. The external auditory canal is winding in its path to the tympanic mebrane. The tympanic bulla is is on the back-bottom of the skull. The middle ear is formed by a cavity region filled with bone and membranous structures bounded by the tympanic membrane and the oval and round windows. The tympanic membrane is flat and seals the ear canal. The anatomy of the paca ear is similar to the guinea pig and from the viewpoint of experimental model has major advantages compared with the mouse ear.

scholarly journals Post Inflammatory Medial Canal Fibrosis: A Case Report

2013 ◽  
Vol 2 (2) ◽  
pp. 69-71
Author(s):  
A Kumar ◽  
K Santosh
Keyword(s):  
Conductive Hearing Loss ◽  
Fibrous Tissue ◽  
External Auditory Meatus ◽  
Solid Core ◽  
Medial Part ◽  
Review Of The Literature ◽  
Soft Tissue Density ◽  
History Of ◽  
Conductive Hearing ◽  
Bony Erosion

Medial canal fibrosis is an interesting type of acquired meatal atresia that is characterized by formation of a solid core of fibrous tissue in the medial part of the external auditory meatus abutting the tympanic membrane. A review of the literature showed that many different terms have been used interchangeably to report the same or similar condition. This is a case of medial canal fibrosis being reported to emphasize the importance in diagnosing this rare but easily treatable disease. A 16 yrs old female presented with bilateral conductive hearing loss & history of recurrent rhinitis & sinusitis. CT Temporal bone showed soft tissue density lesions in bilateral bony EAC (External auditory canal) with no bony erosion & normal middle ear. A diagnosis of Medial canal fibrosis was given. The patient was operated & biopsy of the specimen came out to be inflammatory granulation tissue. Nepalese Journal of Radiology; Vol. 2; Issue 2; July-Dec. 2012; 69-71 DOI: http://dx.doi.org/10.3126/njr.v2i2.7689

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