Quantitative Assessment of Lateral Tongue Movement Using Ultrasonography in Healthy Children and Adults

Aim Tongue movement is essential for oral functions, including mastication, swallowing, and speech articulation; however, objective methods for evaluating lateral tongue movement remain limited. This study aimed to develop an ultrasonography‐based method for quantitatively assessing lateral tongue movement in healthy adults and school‐aged children and to examine its association with tongue pressure. Methods Twenty‐five healthy children and 16 healthy adults participated in the study. Coronal ultrasonographic images were acquired at rest and during maximum lateral tongue movement. The angle between the tongue axis at rest and during maximum lateral movement was measured using ImageJ and defined as the maximum lateral tongue movement angle. Sex differences, right–left differences, and associations with tongue pressure were analyzed. Tongue pressure was measured only in adults. Results The mean right and left lateral tongue movement angles were 9.12° ± 3.49° and 8.32° ± 2.61°, respectively, in adults, and 11.48° ± 3.75° and 9.03° ± 2.92°, respectively, in children. A significant right–left difference was observed only in children, with no significant differences between age groups. Tongue pressure was not significantly correlated with lateral tongue movement angle. Conclusion Ultrasonography enabled quantitative assessment of lateral tongue movement in healthy adults and school‐aged children. The lateral tongue movement angle did not differ significantly between age groups and was not associated with tongue pressure, suggesting that these measures reflect distinct aspects of tongue function. Ultrasonography may provide a simple, noninvasive method for multidimensional assessment of oral function.