Glottal adduction is a primary laryngeal variable that helps to determine g
lottal configuration and phonatory output. Greater adduction of the vocal f
olds can be produced by narrowing the gap between the vocal processes or by
bulging the medial surface of the vocal folds. This study examined phonato
ry effects due to changing the degree of bulging using a computational mode
l. Bulging was modeled as a quadratic surface and was related to active mus
cle stress. Results indicated that bulging had a significant effect on glot
tal now resistance, maximum glottal width and area, and mean glottal volume
velocity. The results are discussed relative to clinical issues of hyperfu
nction.