[The role of the soft palate in respiration].

The soft palate is a muscular fold suspended from the posterior border of the bony palate and extending downwards and backwards into the oropharynx. Usually, the soft palate and tongue are in tight apposition, closing the oropharyngeal isthmus; the soft palate can however rise and touch the posterior pharyngeal wall, closing the nasopharynx: thus the soft palate regulates the flow of air through nose and/or mouth. During oronasal breathing (as during exercise, speech or smoking) the impedance of naso and oropharynx respectively is determined by the position of the soft palate. Hence partitioning of the airflow through nose and mouth will depend on the latter. This is true in both adults and babies. Babies are not obligatory nasal breathers (as was previously thought). This applies as well as to near miss for sudden infant death syndrome babies. The soft palate is also involved in the genesis of snoring and the sleep apnea syndrome.