ABSTRACT
INTRODUCTION In this chapter, the major biomechanical properties that lead to partial collapse and occlusion of the upper airway are reviewed. It is now generally agreed that obstructive sleep apnea is due to changes in either the structural components of the upper airway or alterations in the neuromechanical function that lead to upper airway occlusion during sleep. However, to date, it has been particularly diffi cult to discern the relative contribution of the neural mechanical and the structured alterations to the upper airway dysfunction. In part, the diffi culty stems from the inability to perform all structural or neural studies during the sleeping state. It has been necessary to derive many of the structural alterations from imaging studies that by necessity need to be performed during wakefulness because of the marked instability of airway function during sleep. Moreover, studies that examine mechanical alterations have generally required anesthesia to remove the neural contribution to upper airway dysfunction.
