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Frontiers in Bioengineering and... 2022The middle ear is part of the ear in all terrestrial vertebrates. It provides an interface between two media, air and fluid. How does it work? In mammals, the middle ear... (Review)
Review
The middle ear is part of the ear in all terrestrial vertebrates. It provides an interface between two media, air and fluid. How does it work? In mammals, the middle ear is traditionally described as increasing gain due to Helmholtz's hydraulic analogy and the lever action of the malleus-incus complex: in effect, an impedance transformer. The conical shape of the eardrum and a frequency-dependent synovial joint function for the ossicles suggest a greater complexity of function than the traditional view. Here we review acoustico-mechanical measurements of middle ear function and the development of middle ear models based on these measurements. We observe that an impedance-matching mechanism (reducing reflection) rather than an impedance transformer (providing gain) best explains experimental findings. We conclude by considering some outstanding questions about middle ear function, recognizing that we are still learning how the middle ear works.
PubMed: 36299283
DOI: 10.3389/fbioe.2022.983510 -
JPMA. the Journal of the Pakistan... Feb 2023To determine gender-based morphological variations in malleus.
OBJECTIVE
To determine gender-based morphological variations in malleus.
METHODS
The cross-sectional descriptive study was conducted at the Ear-Nose-Throat and Radiology departments of a public-sector hospital in Karachi, from January 20 to July 23, 2021, and comprised subjects of either gender aged 10-51 years who had intact ear ossicles. They were divided into equal male and female groups. After history and a thorough examination of the ear, high-resolution computed tomography scan of petrous temporal bone was done. The images were studied for malleus, to measure the parameters of its head width, length and shape of manubrium, and total length of malleus for possible morphological variations along gender lines. Data was analysed using SPSS 23.
RESULTS
Of the 50 subjects, 25(50%) were males with mean width of the head 3.04±0.34mm, mean length of manubrium 4.47±0.48mm, and mean total length of malleus 7.76±0.60mm. The corresponding values in 25(50%) females were 3.00±0.28mm, 4.31±0.45mm and 7.41±0.51mm. The total length of malleus between both genders was significantly different (p= 0.031). The shape of manubrium was straight in 10(40%) males and 8(32%) females, and curved in 15(60%) males and 17(68%) females.
CONCLUSIONS
Width of head, length of manubrium and total length of malleus were different in gender terms, but the total length of malleus was significantly different.
Topics: Female; Humans; Male; Malleus; Cross-Sectional Studies; Hospitals, Public; Public Sector; Social Group
PubMed: 36800718
DOI: 10.47391/JPMA.6307 -
Tomography (Ann Arbor, Mich.) Sep 2022The aim of this research was to assess possible relationships between petrotympanic fissure (PTF) characteristics, malleus position, and temporomandibular joint...
The aim of this research was to assess possible relationships between petrotympanic fissure (PTF) characteristics, malleus position, and temporomandibular joint disorders (TMD). A retrospective study was performed, including patients with TMD. Magnetic resonance imaging (MRI) and cone-beam computed tomography (CBCT) examination were used to evaluate temporomandibular joint (TMJ) disc position and condylar bone changes. Fifty-eight TMJs from twenty-nine patients (23:6 females: males) were assessed. Erosive changes (DDR-disc displacement with a reduction of 6 (24%), DDwR-disc displacement without a reduction of 8 (61.5%) vs. normal disc position 3 (15%), = 0.012) and condyle osteophytes production (DDR 6 (24%), DDwR 9 (69.2%) vs. normal condyle 7 (35%), = 0.012) were more frequent in subjects with disc displacement compared to normal disc position; malleus was closer to PTF in cases with erosive changes (median 2.15 interquartile range: (1.85-2.75) vs. 2.75 (2.25-3.15), = 0.029) as well as those with condylar osteophytosis (2.25 (1.91-2.75) vs. 2.75 (2.33-3.32), = 0.015); the PTF length was higher in cases with condylar osteophytosis compared to those without (4.45 (3.50-4.77) vs. 3.67 (3.34-4.28), = 0.039). The disc position and disc shape were not related to PTF or malleus position. Malleus position and PTF dimensions were not associated with the PTF type. In cases with erosive changes and condylar osteophytosis, malleus was closer to PTF.
Topics: Male; Female; Humans; Malleus; Temporomandibular Joint; Retrospective Studies; Temporomandibular Joint Disorders; Temporomandibular Joint Disc; Tongue Diseases
PubMed: 36287803
DOI: 10.3390/tomography8050204