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Background: Upper oesophageal sphincter (UES) serves as an important anatomical and functional landmark during swallowing. However, the precise UES location before and during swallowing has not been well established. Objective: This study aimed to determine upper oesophageal sphincter (UES) location and displacement during swallowing accounting for sex, age, and height in healthy adults using 320‐row area detector computed tomography (320‐ADCT). Methods: Ninety‐four healthy adults (43 males; 22–90 years) underwent 320‐ADCT scanning while swallowing one trial of 10 mL honey thick barium. UES location at bolus hold and at maximum displacement and vertical displacement during swallowing were identified using the coordinates and the section classification of vertebrae (VERT scale). The differences and correlations of UES location and distance in terms of sex, age, and height were analysed using Mann–Whitney U test and Spearman's correlation coefficient. Results: UES locations at bolus hold and at maximum displacement were significantly lower and UES vertical displacement was significantly larger in males than in females (p <.001). UES location at bolus hold became lower with increasing age (r = −.312, p =.002), but the negative correlation was low at maximum displacement (r = −.230, p =.026), resulting in larger vertical distance with ageing. UES locations showed high negative correlation at bolus hold with height (r = −.715, p <.001), and showed moderate negative correlation at maximum displacement with height (r = −.555, p <.001), although this effect was unclear when analysed by sex. Conclusion: Males showed lower UES location and larger displacement than females. The impact of age was evident with lower location before swallowing and larger displacement during swallowing. Differences observed by sex were not completely explained by using the VERT scale to adjust for height. [ABSTRACT FROM AUTHOR]

Objective: This study investigated the effects of bolus consistency on pharyngeal volume during swallowing using three‐dimensional kinematic analysis. Methods: Eight subjects (2 males and 6 females, mean ± SD 44 ± 10 years old) underwent a 320‐row area detector scan during swallows of 10 mL of honey‐thick liquid and thin liquid. Critical event timing (hyoid, soft palate, UES) and volume of pharyngeal cavity and bolus were measured and compared between two swallows. Results: The pharynx is almost completely obliterated by pharyngeal constriction against the tongue base for both consistencies. There were no significant differences in maximum volume, minimum volume and pharyngeal volume constriction ratio values between thick and thin liquids. However, the pattern of pharyngeal volume change (decrease) was different. For thick liquids, the air volume started to decrease before the onset of hyoid anterosuperior movement and decreased rapidly after onset of hyoid anterosuperior movement. During thin liquid swallowing, air volume remained relatively large throughout the swallow and started to decrease later when compared to swallowing thick liquids. At onset of UES opening, the bolus volume was not significantly different between thin and thick liquids; however, air volume was significantly larger when swallowing thin liquids, which made the total volume of the pharyngeal cavity larger. Conclusion: This difference between the two consistencies is associated with differences in tongue motion to propel the bolus and clear the pharynx from possible residue. [ABSTRACT FROM AUTHOR]