Obstructive sleep apnea syndrome: a complex disorder of the upper airway.

The pathophysiologic basis for obstructive sleep apnea syndrome (OSAS) is complex, involving the properties of the pharynx, the muscular forces that support its patency, and the homeostatic control mechanisms of respiration. The anatomic basis for OSAS is the skeletal structure of the head and neck as it is reflected in the soft tissue structures comprising and supporting the upper airway. Study of patients with craniofacial anomalies that result in OSAS, and application of similar study techniques to OSAS patients without apparent craniofacial anomalies, point up similarities and lead to a greater understanding of the anatomic aspects of OSAS.