Catching the Wave: An Exploration of Posterior Pharyngeal Wall Movement in Healthy Swallowing

ABSTRACT Objective(s) Serial pharyngeal constrictor muscle contraction during swallowing can be seen fluoroscopically as a wave of posterior pharyngeal wall (PPW) movement. We characterized PPW thickness at rest and during swallowing at three anatomical levels (C2, C3, C4), accounting for effects of sex, age, and task. Methods Videofluoroscopies were performed in 80 healthy adults (40 males, 40 females), aged 18–90 years. PPW thickness was measured frame‐by‐frame at the inferior borders of C2, C3, and C4 from bolus‐passing mandible to swallow rest on sips of thin liquid and teaspoons of mildly thick liquid. Analyses of variance were used to identify sex, age, and task effects. Results At rest, PPW thickness increased from C2 and C3 to C4. Older participants had reduced C2 PPW thickness at rest and during swallowing. Females had greater PPW thickness than males across all levels at rest and at C3 during swallowing. Maximum PPW excursion events at C2 and C3 coincided with maximum pharyngeal constriction and UES closure, respectively. Young males showed longer latencies to C2max than young females, while females of all ages showed longer latencies to C3max and C4max. Alterations of the typical C2max < C3max < C4max sequence of PPW excursion were more common in older participants. There were no task differences for any measures of PPW thickness or excursion. Conclusion This exploratory study suggests that measures of PPW thickness can reveal age‐ and sex‐related differences in pharyngeal muscle bulk and contraction. Future studies are needed to confirm sensitivity to changes related to medical conditions or after dysphagia intervention. Level of Evidence 4.