Mechanisms of the Gas Exchange in the Normal Human Middle Ear

Mucosal Surface Area Determines the Middle Ear Pressure Response Following Establishment of Sniff-Induced Underpressures

“…Two mechanisms have been identified that change ME gas volume: i) the pressure gradient-driven, bolus exchange of mixed gas between the nasopharynx and ME during Eustachian tube (ET) openings, and ii) the gradientdriven, diffusive exchange of gases between the ME and blood (3). Classically, these two factors have been assumed to have opposing effects, with the ET supplying gas and trans-mucosal exchange depleting it (1,2). This interpretation is consistent with the measured gas partial pressure gradients between ME and blood, where for both healthy and diseased MEs, approximate partial pressure equilibria for O 2 , CO 2 and H 2 O, but an excess ME N 2 partial pressure, were reported (4,5).…”

“…The mechanism of middle ear (ME) pressure regulation remains a poorly understood aspect of physiology (1)(2)(3). Because the ME is a relatively non-collapsible, temperature-stable gas pocket, its pressure is affected by mechanisms that alter the contained volume of gases.…”

Pre-operative Indicators of Ossicular Necrosis in Tubotympanic CSOM

“…According to literature an ABG of greater than 30 dB at 2 kHz and greater than 40 dB at 4 kHz increased the probability of ossicular discontinuity to 89 % [16]. Narrow ABG at low frequencies suggested absence of ossicular discontinuity and wide ABG at higher frequencies suggested presence of ossicular discontinuity.…”

Book review

“…The middle ear muscles are supposed to be activated spontaneously when articulation starts. The tensor tympani is spontaneously active when certain muscles are contracted (Kobrak 1959;Ingelstedt and Johnson 1966). The only report of spontaneous activity in the stapedius muscle because of activity in other muscles was made by McCall and Rabuzzi (1973) on cats.…”