Velopharyngeal inadequacy in the absence of overt cleft palate.

Velopharyngeal inadequacy in the absence of overt cleft palate may be due to any one, of any combination, of the following: intraorally visible stigmata associated with submucous defects (any combination of bifid uvula, muscular diastasis of the soft palate, bony defect of the hard palate); "occult" anatomical defects of the levator palatini or musculus uvulae, detectable only by nasopharyngoscopy or by operative dissection; anatomic disproportion between the size of the nasopharynx and the length of the hard and/or soft palate; mechanical interference with motion of the velopharyngeal system occurring as a result of scarring or contracture, and possibly as a result of interposition of the upper poles of the faucial tonsils between the velum and the posterior pharyngeal wall; a wide variety of neuromotor deficits, either congenital or acquired, causing reduced and/or incoordinated movement of the velopharyngeal musculature; a learning error of unknown origin which results in velopharyngeal inadequacy only on specific phonemes with all other pressure consonants emitted orally. Submucous defects of the secondary palate do not necessarily produce velopharyngeal inadequacy. Thus, our estimates of both the incidence of submucous defects and of the frequency of genes for clefting in any given population are undoubtedly low. Finally, "stress velopharyngeal inadequacy" in wind instrument players has been linked to a variety of anatomic findings and is not necessarily accompanied by velopharyngeal inadequacy in speech. This paper will review the historic aspects of velopharyngeal inadequacy and will discuss and analyze the causes outlined above.