Mechanisms Underlying Improvement in Obstructive Sleep Apnea Syndrome by Uvulopalatopharyngoplasty

Figure 3

Streamlines and contour maps of pressure and velocity before UPPP; (a) pressure contour, (b) flow velocity contour, and (c) streamlines. Low-pressure regions are located at the distal velopharynx, oropharynx, and hypopharynx. At the velopharynx, a high velocity indicates a low static pressure. Vertical recirculation and swirl flow is observed where the airway narrows around the epiglottis between the oropharynx and hypopharynx.

(a) Pressure contour

(b) Flow velocity contour

(c) Streamlines of flow