Comparison of the Anatomy of the Eustachian Tube in the Rhesus Monkey (Macaca Mulatto) and Man

1980 ◽  
Vol 89 (1) ◽  
pp. 49-57 ◽  
Author(s):  
William J. Doyle ◽  
Stewart R. Rood

The primate nasopharynx-eustachian tube-middle ear complex is being used to model both the normal and pathologic functions of the human eustachian tube by several researchers. An extensive search of the literature has indicated little detailed information on the primate eustachian tube/middle ear system. This study was undertaken to define the anatomical characteristic of the system in the Rhesus monkey ( Macaca mulatto) and to determine the limits on the use of the monkey as a model of human eustachian tube function. Although the direct application of morphologic data to explain the function of a system is tenuous, the data on the Rhesus monkey eustachian tube appears to be consistent with that published for other mammals. The tensor veli palatini muscle appears to be the only muscle to act directly on the tube and effect tubal dilation. The muscle is attached to the lateral membranous tubal wall along its extrabullar extension. The muscle has an inferior attachment to the posterior hard palate and thus possesses a vector directed inferolaterally; contraction would appear to pull the membranous wall inferiorly and laterally, resulting in the tubal dilation. The eustachian tube relationships of the salpingopharyngeus, levator veli palatini, and internal pterygoid muscles are described. Their possible role in primate tubal function is minimal at best.

1979 ◽  
Vol 88 (1) ◽  
pp. 40-51 ◽  
Author(s):  
Erdem I. Cantekin ◽  
William J. Doyle ◽  
David C. Phillips ◽  
Timothy J. Reichert ◽  
Charles D. Bluestone

The recent studies of the anatomy of the eustachian tube and related structures in the Rhesus monkey ( Macaca mulatto) have shown that the monkey tubal system is similar to the human. This investigation in Rhesus monkeys was an attempt to verify previous studies in other animals that the tensor veli palatini muscle was the only dilator of the eustachian tube. Two unipolar stimulating electrodes were introduced into the foramen ovale, and the mandibular branch of the trigeminal nerve was electrically stimulated. Simultaneously, pressure-flow recordings through the eustachian tube were monitored. Stimulus-response relationships were obtained for five Rhesus monkeys. The degree of tubal dilation by the tensor veli palatini muscle contraction was shown to be a function of stimulating current levels. Artificially induced dilations were quite similar to the physiological dilations during swallowing when these animals were tested alert. Following complete transection of the tensor muscle, regardless of the stimulus level, no tubal dilations were observed. Stimulation of the nerve to the internal pterygoid and stimulation of the levator veli palatini muscle induced only constrictions of the tube. The tensor veli palatini muscle is the only paratubal muscle responsible for active dilation of the eustachian tube in the Rhesus monkey, and its motor innervation is the mandibular division of the trigeminal nerve.


2014 ◽  
Vol 36 (3) ◽  
pp. 115-118 ◽  
Author(s):  
Mehmet Ilhan Sahin ◽  
Safak Gulec ◽  
Umit Perisan ◽  
Ismail Kulahli

2019 ◽  
Vol 133 (7) ◽  
pp. 580-587 ◽  
Author(s):  
B K-H G Franz ◽  
R Patuzzi ◽  
C J Wraight ◽  
G Kay ◽  
A Ng ◽  
...  

AbstractObjectiveTo assess the effect of topical betahistine on Eustachian tube function in subjectively abnormal subjects in a hyperbaric chamber.MethodActive and passive Eustachian tube function was examined using tympanometry in a pressure chamber.ResultsActive Eustachian tube function was tested against the negative middle ear pressure induced by increasing the chamber pressure to +3 kPa. One voluntary swallow decreased middle-ear pressure by a mean of 1.36 kPa. Passive Eustachian tube function was tested by measuring spontaneous Eustachian tube openings as the chamber pressure dropped from +10 kPa to ambient. Four distinct patterns of Eustachian tube behaviour were seen, three of which indicated Eustachian tube dysfunction. Betahistine had no positive effect on Eustachian tube opening, although previous animal studies had suggested a beneficial effect.ConclusionTopical betahistine had no effect on Eustachian tube function. Combining a hyperbaric chamber with tympanometry proved ideal for evaluating Eustachian tube function.


1980 ◽  
Vol 89 (3_suppl) ◽  
pp. 47-54 ◽  
Author(s):  
Erdem I. Cantekin ◽  
David C. Phillips ◽  
Charles D. Bluestone ◽  
William J. Doyle ◽  
Kyle K. Kimes

Previous studies in humans have indicated that functional obstruction of the eustachian tube (ET) is an important factor in the pathogenesis of otitis media with effusion (OME). This type of obstruction appears to be related to the structural properties of the tube, or to an inefficient active tubal opening mechanism, or both. In this study, functional ET obstruction was created in 22 rhesus monkeys ( Macaca mulatta) by surgically altering the tensor veli palatini (TVP) muscle using three different procedures: 1) complete excision of the muscle; 2) transection of the superficial muscle bundle; or 3) transposition of the muscle tendon medial to the hamular process. Prior to surgery, weekly tympanometry, pneumatic otoscopy, and otomicroscopic examinations were performed for a period of at least six months to document middle ear (ME) status. A minimum of four ET function tests were performed on each animal using the inflation-deflation and forced-response tests. Following surgery, these tests and examinations were continued for periods of up to one year. Postoperatively, the animals in which the TVP had been excised developed a sterile ME effusion which proved to be a chronic condition which persisted throughout the follow-up period. Eustachian tube function tests showed a complete absence of any active tubal dilation by swallowing. Animals that had the muscle transected developed abnormal ME pressures, or effusions, or both, which returned to normal in some ears, but which were recurrent or chronic in others. Eustachian tube function tests in these animals showed an initial loss of active tubal function which gradually improved, but not to normal levels, presumably as a result of healing of the muscle. In cases in which the muscle was transposed the ME pathology and ET dysfunction were similar after the surgery, but improved within a short period of time. These data suggest that alteration of the TVP muscle can create functional obstruction of the ET. The severity of ET obstruction depends upon the surgical procedure undertaken. The results of postoperative ET function tests were similar to those recorded from children with recurrent and chronic OME.


2011 ◽  
Vol 120 (4) ◽  
pp. 220-225 ◽  
Author(s):  
J. Douglas Swarts ◽  
Cuneyt M. Alper ◽  
Ellen M. Mandel ◽  
Richard Villardo ◽  
William J. Doyle

1984 ◽  
Vol 92 (3) ◽  
pp. 312-318 ◽  
Author(s):  
Bernt Falk ◽  
Bengt Magnuson

Previous research on eustachian tube function has been devoted mainly to the study of the tubal opening ability and pressure equalization. This article summarizes a series of experimental studies focusing on the closing ability of the tube. Results support the belief that the purpose of the tube should be seen primarily as protecting the middle ear from the extensive pressure variations that physiologically take place in the nasopharynx. A number of studies of diseased ears have shown that tubal malfunction was characterized mainly by a reduced ability to withstand negative pressure in the nasopharynx. Sniffing can evacuate the middle ear, causing high negative intratympanic pressure. It seems likely that this mechanism is involved in the development of middle ear effusion and manifest retraction-type middle ear disease.


1997 ◽  
Vol 106 (7) ◽  
pp. 583-588 ◽  
Author(s):  
Masaharu Sudo ◽  
Isamu Sando ◽  
Akihiro Ikui ◽  
Chiaki Suzuki

Nine normal human temporal bones from persons 16 to 88 years old were studied by computer aided three-dimensional reconstruction and measurement. The length of the eustachian tube (ET) lumen in three portions (from pharyngeal orifice to tympanic orifice: cartilaginous, junctional, and bony) averaged 23.6 ±4.3 mm, 3.0 ± 1.9 mm, and 6.4 ± 2.6 mm. The narrowest portion of the ET lumen was in the cartilaginous portion in all cases: 20.5 ± 4.2 mm from the pharyngeal orifice and 3.1 ± 1.6 mm from the pharyngeal margin of the junctional portion. The cross-sectional area of the narrowest portion was 0.65 ± 0.2 mm2. The tendon of the tensor veli palatini muscle (TVPM) inserted into the lateral lamina in the narrowest portion of the ET lumen in five of nine cases. These results suggest that contraction of the TVPM opens the narrowest portion of the ET lumen to ventilate the middle ear and that this portion also plays a role in protecting the middle ear.


Author(s):  
Abhinav Srivastava ◽  
Puneet Shukla

ABSTRACT Introduction Eustachian tube connects nasopharynx with the tympanic cavity. The normal middle ear has an inherent tendency to lose gas to maintain the middle ear pressure by diffusion into the surrounding tissues and circulation. Materials and methods This cross-sectional study was conducted in 2012 to 2014. A total of 100 ears of 50 consecutive cases undergoing nasal surgery followed by bilateral nasal packing were included in the study and the middle ear pressure and hearing threshold were determined in all the subjects in presurgery, and then after 48 hours of surgery with nasal packing in situ and then at 7 and 30 days of nasal pack removal. Conclusion There is an increase in middle ear pressure transiently for few days while the nasal pack is in situ, which returns to normal in a month after pack removal; but, in chronic nasal obstruction cases, such as nasal polyps, there is persistent negative middle ear pressure, probably due to irreversible changes in the Eustachian tube function. How to cite this article Mohan C, Srivastava A, Shukla P. Effect of Nasal Packing on Middle Ear Pressure. Int J Adv Integ Med Sci 2016;1(2):52-56.


1992 ◽  
Vol 107 (4) ◽  
pp. 511-515 ◽  
Author(s):  
Patrick J. Antonelli ◽  
Steven K. Juhn ◽  
Marcos V. Goycoolea ◽  
G. Scott Giebink

Previous experiments have shown that Pseudomonas aeruginosa may infect the middle ears of chinchillas by way of the eustachian tube and that chinchillas with acute otitis media (AOM) are more susceptible to pseudomonas infection than animals without AOM. The purpose of this experiment was to examine the effects of otitis media with effusion (OME), induced by means of eustachian tube obstruction, on middle ear susceptibility to nasal inoculation of P. aeruginosa. Chinchilla eustachian tubes were obstructed with silicone rubber sponge bilaterally; OME developed in eight animals (11 ears)—three bilaterally and five unilaterally—and persisted for 6 months. Ten chinchillas with normal eustachian tube function served as controls. All animals were nasally inoculated with 5 times 104 colony-forming units of P. aeruginosa. Pseudomonas otitis media developed in eight of 11 OME ears with effusion, none of five ears without OME, and four of 20 control ears (X2 = 11.782, p = 0.003). Therefore, P. aeruginosa can infect the middle ear by way of the eustachian tube. Tubal dysfunction may lead to the development of chronic suppurative otitis media by increasing tubotympanic susceptibility to opportunistic pathogens.


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