A new model of the vocal cords based on a collapsible tube analogy.

Flow through the vocal cords and collapsible tubes passes through a narrow elastic gap whose cross-sectional area varies with the transmural forces induced by the flow. In both systems, the equations used to describe steady flow are the same and have similar dependence on cross-sectional area. Since collapsible tubes have been shown to be flow-controlled nonlinear resistances (QNLR) analogous to transistors, it is expected that the vocal cords will also exhibit the QNLR property for steady flow. A new equivalent circuit including a transverse impedance to represent wall motion is postulated for the vocal cords based on the tube analogy. Collapsible tubes oscillate when the magnitude of their negative dynamic resistance is greater than the ac resistance of the external circuit plus parasitic tube impedances. Self-oscillation conditions for the cords should be the same. since they are common to all negative resistance systems of QNLR type.