gms | German Medical Science

Figure

Figure 23: Position 4 – upper esophageal sphincter during eructation in a retrograde view (on the right side, a vertebra is visible (*)); a – upper esophageal sphincter at rest without increased pressure; b – the lower sphincter was open (pressure balance); the space of the upper esophageal sphincter is wider because of increased pressure, the circular muscles are tense (yellow color); c – the circular fibers open first (NB time code); d – the cricopharyngeal muscle is open, its contours are visible (NB time code).