“High-Resolution Intraoral Ultrasonography of the Intrinsic Tongue Muscles: Detailed Anatomical Visualization”

Abstract Purpose The tongue plays a key role in speech and swallowing, and its intrinsic muscles enable fine coordinated movements. High-resolution ultrasonography is a non-invasive method that allows detailed visualization of tongue structures and blood vessels. This study investigated the morphology of the intrinsic tongue muscles and deep lingual artery by correlating the high-resolution intraoral ultrasonography with known anatomical structures. Methods Ultrasonographic examinations were performed on 33 Korean adults (6 males and 27 females; mean age: 34.9 ± 12.3 years) using a B-mode system with a 15 MHz hockey-stick transducer. Five predefined areas on the dorsal and lateral tongue surfaces were systematically scanned. A total of 182 images were acquired to evaluate intrinsic tongue structures and the deep lingual artery. Muscle visualization rates were summarized descriptively, and Fisher's exact test was used to examine age-related differences in visualization status. Results The intrinsic tongue muscles (superior longitudinal, transverse lingual, vertical lingual, and inferior longitudinal muscles) were distinctly visualized in layered structure from surface inward. Muscle separation was clear on the dorsal surface, though vertical and transverse lingual muscles appeared in the same layer. Visualization detail decreased slightly in the tongue tip and lateral regions. The deep lingual artery was identified in 70.6% of participants, primarily in the anterior tongue, at a mean depth of 0.9 cm (range, 0.6–1.2 cm). An age-related trend toward lower visibility of the right vertical lingual muscle was observed in older participants (P = 0.123). Conclusion High-resolution intraoral ultrasonography successfully provided detailed, anatomically consistent visualization of intrinsic tongue muscles and the deep lingual artery, supporting its utility for both clinical assessment and educational purposes.