The volume of swallowed bolus affects the pharyngeal transit duration. The sex and corporal height of individuals may likely influence this effect. The aim of this investigation was to determine the influence of sex and corporal height on the pharyngeal transit modification produced by the swallowed bolus volume. Forty healthy volunteers, 20 men and 20 women, including tall 10 men and 10 women, corporal height: Videofluoroscopic evaluation of swallowing was performed with the subjects in the sitting position.
Each individual swallowed three 5 mL and three 10 mL boluses of liquid barium in a random sequence. The durations of oral transit, pharyngeal transit, pharyngeal clearance, hyoid movement, upper esophageal sphincter opening and oral-pharyngeal transit were evaluated.
In men and women, and in taller and shorter individuals, the increase of the swallowed liquid bolus volume from 5 mL to 10 mL causes a faster transit of the bolus tail from the oral-pharyngeal transition to the upper esophageal sphincter and an increase in the duration of the upper esophageal sphincter opening, with similar alteration in men and women and in taller and shorter individuals.
An increase in the swallowed liquid bolus volume from 5 mL to 10 mL causes a faster pharyngeal bolus transit and a longer bolus transit through the upper esophageal sphincter, with similar alterations in men and women and in shorter and taller individuals. Several studies have demonstrated that sex can be a factor in influencing the phases of swallowing 5 , 6 , with women having longer oral-pharyngeal transit durations than men 6 - However, several investigations did not find that sex influences the timing of swallowing events 3 , 11 , suggesting that the observed differences are likely caused by different heights of individuals, although previous results have shown a week correlation between height and some swallowing events 3.
Superior hyoid displacement is greater in taller individuals than in shorter individuals Height and sex have an influence on the size of the hypopharynx and the larynx, with an independent and interacting effect on the morphology of the pharynx and the larynx In women the pharynx air column is surrounded by smaller structures, and there are no differences related to pharyngeal air column measurements The pharyngeal cross-sectional area measured with individuals in the sitting position is greater in men than in women These anatomical differences may influence the modifications caused by the swallowed bolus volume.
The differences in swallowing timing in men and women, and with the swallowed bolus volume, may be important in patients with dysphagia. Some patients may not be able to swallow higher volumes because of their incapacity to change the swallow dynamics and to increase the oral and pharyngeal capacity with the increase in bolus volume. Considering the hypothesis that the swallows modification caused by a 5 mL to 10 mL increase in liquid bolus volume may be different in men and women and in shorter and taller individuals, the objective of this investigation was to evaluate the modification of the oral and pharyngeal transit durations after swallows of 5mL and 10mL in men and women with different body heights.
All volunteers had no symptoms; had no digestive, neurologic or endocrine disease; and did not undergo previous surgery. A written informed consent was obtained from each participant and the anonymity of each volunteer was preserved.