Velopharyngeal insufficiency due to hypoplasia of the musculus uvulae and occult submucous cleft palate.

With the help of nasopharyngoscopy, it was possible to delineate specific morphologic changes in the palates of patients with velopharyngeal insufficiency, without an overt cleft and without the triad of symptoms of submucous cleft palate, visible through the oral cavity. Such malformations are part of the broad spectrum of the faulty midline mesodermal fusion of the palate. This anomaly is aptly called occult submucous cleft palate, because it can only be detected by viewing the functioning palate from the nasal surface. The musculus uvulae is either absent or deficient and is frequently associated with some degree of muscular diastasis that does not involve the oral surface. Like the cleft of the secondary palate, the submucous cleft palate often occurs as part of a generalized syndrome of multiple malformations.