Obstructive sleep apnea is a common medical disorder with significant
adverse health consequences. The pathogenesis of pharyngeal obstructio
n during sleep, however, remains elusive. This article addresses the k
ey mechanisms of upper airway (UA) obstruction including the role of t
ransmural pressure, pharyngeal compliance, pharyngeal dilating muscle
activity and non-neuromuscular factors. A proposed scheme of the patho
physiology of UA obstruction is outlined.