Figure 15 - Coordination between the UES and glottal function during belching.

Figure shows temporal relationship among the function of the glottis, UES, and hyoid bone and pressure phenomena of esophagus and stomach during belching induced by intraesophageal injection of 40 mL of room air. Figure is constructed using videoendoscopic, videofluoroscopic, manometric, and electromyographic (EMG) data obtained concurrently. Belch event begins with vocal cord adduction and ends with return to resting position. All other events, including UES opening and closure, occur while cords are fully adducted and thereby the introitus to the trachea is closed. Fluoroscopic UES opening begins 0.35 0.08 sec after onset of hyoid bone movement. VC-Ad-O, onset of vocal cord adduction; VC-Ad-Max, maximum onset of vocal cord adduction; VC-Ab-O, onset of vocal cords opening; VC-Ab-Max, return of vocal cords to resting position; EPI-O, onset of increase in intraesophageal pressure; AEA-O, onset of approximation of arytenoids toward base of epiglottis; GPI-O, onset of increase in intragastric pressure; EMG-O, onset of EMG signal recorded from geniohyoid, mylohyoid muscle groups; UESR-O, onset of UES relaxation recorded manometrically. (Source: Shaker et al.⁴ with permission from the American Physiological Association)