Abstract
Measurement of the swallowing pressure using an intraluminal manometer is very useful for understanding the swallowing mechanism. However, if a catheter-probe method is employed for measuring the swallowing pressure, the probe itself moves, causing a discrepancy in the time peristaltic contraction wave relationship. This makes interpretation of the data relating to the swallowing pressure difficult. To solve this problem, we also recorded, under visualization by lateral x-rays, the electromyograph and the intraluminal pressure and studied the mechanism of generation of the swallowing pressure, mainly on the basis of analysis of the movement of the pressure sensor. The results were as follows. (1) The resting pressure peaked at the 6th cervidcal vertebra with a value of 44± 19mmHg, and the width of the positive resting pressure zone was 32± 6mm. (2) The movement of the sensor at the time of swallowing resembled the lifting movement of the larynx, showing a trapezoidal pattern. (3) The maximum positive pressure in the pharynx was biphasic, but it was not generated before the sensor reached the highest posision. It was generated as a pharyngeal contraction wave when the posterior end of a swallowed bolus (barium) passe the pharynx after the sensor had reached the highest position. (4) The negative pressure in the upper esophageal sphincter (UES) was generated immediately before the anterior end of the bolus passed the sensor. This negative pressure is generated due to the anatomical structure of the pharynx, including the UES, a state of suction in caused by passage of a swallowed bolus. (5) EMG of the geniohyoid was usable as an indicator of the initiation of swallowing. However, the time from initiation of geniohyoid contraction to the maximum positive pressure was not constant. Therefore, the cricopharyngeus should also be included in future studies on the second phase of swallowing and the physiology of the UES.
