Abstract
Vibrations of the intact and perforated tympanic membranes of the fresh dog's cadaver were studied by the high speed motion film. The auditory bulla was exposed preserving the tympanic membrane, ossicles, tympanic muscles and tendons. The picture was taken from the side of the tympanic membrane. Vibrations of the tympanic membrane with 250 to 1000 Hz tone stimuli above 100 dB SPL were analyzed by a film motion analyzer. Vibrations of the intermediate zone of the membrane was greater than that of the central and peripheral zones. Vibrations of the anterior superior quadrant was greater than that of the anterior inferior quadrant in the dog. This difference was marked with low tone stimulations. A small perforation at the anterior inferior quadrant greatly decreased the vibration of the tympanic membrane with 250 to 500 Hz tone stimuli. The decrease in vibration amplitudes was greater at the anterior superior quadrant.
