Figure 11 - Movement of the hyoid bone during belching (a) and swallowing (b).

Open circles indicate UES opening observed by videofluoroscopy. Although hyoid bone movement during swallowing was invariably upward, forward, and counterclockwise, its movement during belching was mainly anterior and clockwise. The magnitude of hyoid bone movement during belching was significantly less than its movement during swallowing. Hyoid bone movement is an indication of the magnitude of the distraction forces that open the UES (p <.02). (Source: Shaker et al.,¹⁰⁶ with permission of the American Physiological Society.)