The upper airway in obstructive sleep apnoea: state of the art.

The upper airway is a complex structure, prone to repetitive collapse in obstructive sleep apnoea (OSA). This review discusses the pathophysiological aspects of OSA, with a focus on the anatomy and pathophysiology of upper airway obstruction. This disorder is characterised by different mechanisms that constitute its pathology, which may all contribute to apnoea presence and severity. These include pharyngeal anatomy, collapsibility, upper airway muscle responsiveness, loop gain and arousal threshold. Identification of interindividual differences in the underlying mechanisms of OSA offers promise for a more targeted approach to OSA management.