Nasopharyngeal profile and velopharyngeal valve mechanism.

Proper management of velopharyngeal insufficiency requires an understanding of normal velopharyngeal anatomy and function. The present cephalometric study correlates the nasopharyngeal profile at rest with velopharyngeal function as observed by nasendoscopy and fluorographic and videofluoroscopic studies. Fifty-two normal individuals and 23 patients with insufficient velopharyngeal valves were examined. A correlation was found between nasopharyngeal profiles at rest and the closure patterns of the velopharyngeal valve. It was found that when existent, Passavant's ridge is subsequently formed where thick soft tissue corresponding to the superior constrictor muscle is found beneath the mucosa of the posterior pharyngeal wall at rest. Our conclusion is that Passavant's ridge is formed by the superior constrictor. The present study represents additional confirmation that differences in velopharyngeal closure patterns are the result of differences in anatomy. A biomechanical model of velopharyngeal valving is presented based on individual spatial muscular orientation and the hierarchical recruitment of the velopharyngeal muscles. This recruitment is progressive and is dependent on the effort required to achieve tighter velopharyngeal sealing.