Pharyngeal Collapse 2D: Starling-Resistor Cross-Section

The upper airway that collapses during an obstructive sleep apnea event is not blocked by a solid object — it is a flexible tube with no rigid skeleton, held open only by muscle tone against the surrounding tissue pressure. This 2D companion model renders that tube as a longitudinal cross-section silhouette and drives it with the same self-consistent Starling-resistor solver used in Pcrit research: a balance between the anatomical critical closing pressure, active dilator-muscle tone, the diaphragm's inspiratory drive, and any CPAP splinting pressure, iterated every frame so narrowing and flow feed back on each other exactly as they do physiologically. Increase respiratory drive on a positive-Pcrit airway and watch flow accelerate through the narrowest point, Bernoulli-drop the local pressure below Pcrit, and snap the airway shut — then dial in CPAP and watch the same airway pop back open, which is exactly why pneumatic splinting, not sedation or muscle stimulants, is first-line OSA therapy.