Simultaneous assessment of pharyngeal wall and velar displacement for selected speech sounds.

Velar and pharyngeal wall displacements were studied simultaneously by using conventional lateral-view radiography and frontal-view tomography. Twenty-five normal adult male and female subjects were utilized. Major results pertaining to lateral pharyngeal wall displacements during speech include the following. 1) At more superior levels of the pharynx, greater mesial displacements occurred for nonnasal compared to nasal speech sounds and no significant differences were noted among the nonnasal speech sounds studied. 2) At an inferior level of the pharynx, mesial displacements were greater for low vowels compared to the other speech sounds studied but some lateral (outward) movements were observed during high vowel production for some subjects. 3) Greatest mesial displacements for all subjects ad speech sounds studied occurred at the level of and just below the plane of the hard palate. Low correlations between velar and lateral pharyngeal wall displacements were obtained for most subjects. The results do not support the hypothesis that the levator veli palatini muscle is solely involved in both velar and lateral pharyngeal wall movements.