ABSTRACT
The upper airway is composed of the nose, the pharynx, the larynx, and the
extrathoracic trachea. The segment of greatest interest is the pharynx, where
partial and/or complete airway obstruction occurs during sleep in patients
with the obstructive sleep apnea syndrome (OSAS). Under neural and chemical
control, contraction of the pharyngeal muscles surrounding the collapsible
conduit of the pharynx modulates its size and stiffness according to the required
purpose. The objectives of this chapter are to describe normal pharyngeal airway
maintenance achieved by the interaction between the pharyngeal muscles and
structures during sleep and to share new information that may relate to the
pathophysiology of sleep-disordered breathing.
