en Trauma Surgery Trauma Surgery Original Research: Clinical Science Original Research: Clinical Science Background: With respect to physical relations in force and pressure, we hypothesized that the prevalence of traumatic tympanic membrane perforation in patients with a patulous Eustachian tube is greater than normal, because in Eustachian tube patency, the internal air pressure of the middle ear will not increase after compression, subsequent to trauma. Therefore the force upon the tympanic membrane may cause it to perforate easier. Methods: In this study we evaluated 45 patients with traumatic tympanic membrane perforation. After otoscopy, modified inflation-deflation test was performed to determine the opening, closing, and residual pressure of the Eustachian tube. Results: Approximately 60 percent had a patulous Eustachian tube, 27% had poor Eustachian tube function and 13% had normal Eustachian tube function. Conclusion: It appears that patients with a patulous Eustachian tube are probably at high risk for traumatic tympanic membrane perforation. Patulous Eustachian Tube, Traumatic Tympanic Membrane Perforation. 287 289 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-298-4&slc_lang=en&sid=1 Ali Asghar Peyvandi aliapeyvandi@yahoo.com 20031947532846003170 20031947532846003170 Yes Department of Audiology, Shahid Beheshti University of Medical Sciences, Rehabilitation Faculty, Mohammad Ebrahim Mahdavi 20031947532846003171 20031947532846003171 No