SHAPE AND DERIVED GEOMETRICAL PARAMETERS OF THE ADULT, HUMAN TYMPANIC MEMBRANE MEASURED WITH A PHASE-SHIFT MOIRE INTERFEROMETER

The shape of the tympanic membrane is fairly complex and seems to be a significant importance in the coupling of the acoustic sound pressure in the external ear canal to the motion of the middle ear ossicles. A moire shift interferometer was used to measure with great precision the shape of the external surface of human tympanic membrane. The dense matrix of z(x,y) values thus obtained is used to calculate different geometrical parameters (area, curvature,..). We show further how the same data can be used to specify exactly the shape of the tympanic membrane in a mathematical finite-element model of the middle ear.