Epiglottic movements during breathing in humans.

1. Using X-ray fluoroscopy we measured antero-posterior (A-P) and cranio-caudal (C-C) displacements of the epiglottic tip (ET), corniculate cartilage and hyoid bone in seven seated, normal human subjects (age 34 +/- 3 years; mean +/- S.E.M.; 4 males, 3 females) breathing via a nasal mask or mouthpiece with (RL) and without (UB) a fixed resistive load. 2. During UB, via either mouth or nose, there were no significant A-P ET movements. During RL via the nose the ET at peak expiratory flow was 2.6 +/- 1.3 mm cranial to its position at peak inspiratory flow (P < 0.05, ANOVA). C-C movements of the ET correlated strongly with C-C movements of the corniculate cartilage and hyoid bone. 3. The ET, corniculate cartilage and hyoid bone (at zero airflow) were situated more caudally during oral UB than for any other condition. 4. When present, epiglottic movements during breathing do not appear to be independent of those of the larynx and hyoid. Furthermore, epiglottic position may be related to the level of upper airway resistance.