Holographic interferometry applied to the investigation of tympanic-membrane displacements in guinea pig ears subjected to acoustic impulses

The displacements of the tympanum of guinea pigs undergoing the action of acoustic impulses were investigated using holographic interferometry. The motion of the umbilicus is approximately 7.5 times smaller than that of the maximum elongation point of the tympanic membrane located between the umbilicus and the annulus fibrocartilagineus in the prolongation of the manubrium mallei. The results attempt to explain why tympanic lesions originated under the action of acoustic impulses frequently appear in the lower area of the pars tensa in the case of guinea pigs. The holographic visualization of tympanic-membrane displacements appears to offer a number of practical applications allowing to throw light into the transmission of acoustic energy at the level of the tympanic membrane. Subject Classification: 65.24; 35.65; 80.50.