Fig. 5From: Threshold of the upper airway cross-section for hypopnea onset during sleep and its identification under waking conditionThe shape change in the oropharynx cross-section of the upper airway after elevating the legs for 8 min. Compared to the reference (a), there was a significant size reduction in the lateral direction, while the change in the anteroposterior direction was small after 8 min of leg raising (b)Back to article page