What are the three primary structures involved in velopharyngeal closure?

The three primary structures involved in velopharyngeal closure are the velum, lateral pharyngeal walls, and posterior pharyngeal wall. This closure is essential during speech and swallowing, as it separates the oral cavity from the nasal cavity, preventing air from escaping through the nose and directing it solely through the mouth.

The velum, or soft palate, elevates to contact the lateral pharyngeal walls and the posterior pharyngeal wall. This action creates a barrier that prevents nasal resonance during speech and avoids the escape of food into the nasal cavity during swallowing. Understanding these structures is crucial in assessing and treating speech disorders related to velopharyngeal insufficiency, where the closure is inadequate.

The other options do not accurately represent the structures involved in this specific physiological process. The hard palate, while important in speech production, does not actively participate in velopharyngeal closure. Similarly, while the nasal septum, tonsils, vocal cords, and epiglottis play roles in other aspects of speech and swallowing, they are not primary contributors to the mechanism of velopharyngeal closure itself.