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

Objectives: This study investigated the morphology of the intrinsic tongue muscles and deep lingual artery via comparing the high-resolution intraoral ultrasonography with known anatomical structures. Method: 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. To examine these associations, chi-square tests and independent t-tests were employed. Results: The intrinsic tongue muscles (superior longitudinal, transverse lingual, vertical lingual, and inferior longitudinal muscles) were distinctly visualized in layered structures 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). Exploratory analysis showed participants with visible right vertical lingual muscle were younger (31.1 ± 9.7 years) than those without (36.5 ± 13.1 years; P = 0.250, Cohen's d = 0.44), suggesting a potential age-related pattern requiring validation in larger studies. Conclusions: 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.