Radial asymmetry characterized the upper esophageal sphincter pressures.

The characteristics of the upper esophageal sphincter (UES) motor functions remain unknown in Chinese. Twenty-three volunteers (M/F: 10/13, age: 19-40) without any pharyngeal/esophageal motor disturbance underwent UES measurement in the left decubitus position using a low compliance pneumohydraulic infusion system. These measurements included the location of UES from nostril, its resting pressure, and the responses to swallow. Mean UES resting pressures measured with three 120 degrees oriented manometric orifices were 22.6 +/- 7.7 mmHg, 16.9 +/- 8.6 mm Hg and 20.7 +/- 9.6 mmHg respectively (p < 0.05). In regard with the swallow-induced UES relax ability, the relax interval, the post-relax contractile amplitude and interval, neither dry swallow nor wet swallow led to a different result. Mean measured UES location from the nostril with the most proximal orifice of probe was 29.3 +/- 2.3 cm. This location did correlate very well with body height (r = 0.60, p < 0.01). In conclusion, this study demonstrates that the UES resting pressures exhibit a radial asymmetry, and that the type of swallow does not influence UES responses. Furthermore, an equation based on the body height may predict the most appropriate UES position.