Two- and Three-Dimensional Ultrasonographic Characterization of the Modiolus and Adjacent Facial Muscles in Healthy Adults

Objectives: This study aimed to investigate the modiolus in healthy adults using high-frequency ultrasound, establish standardized scanning protocols, and clearly delineate the two- and three-dimensional sonographic features of the modiolus and its associated facial muscles. Methods: Healthy adult volunteers were examined using a Philips ultrasound system equipped with high-frequency linear and broadband linear transducers. Bilateral scans of the modiolus and adjacent facial muscles were performed to determine optimal scanning approaches and characterize the sonographic appearances in both two- and three-dimensional modalities. Results: High-frequency ultrasound, with its superior soft tissue resolution, enabled clear visualization of the modiolus and related facial expression muscles. The scanning protocol for this anatomical region was successfully established, and its typical sonographic features were described. The findings indicate that high-frequency ultrasound is a reliable imaging tool for defining the ultrasonographic anatomy of the oral commissure modiolus region. Conclusions: High-frequency ultrasound provides detailed anatomical visualization of the modiolus and associated facial muscles and may serve as an important reference for clinical and research applications involving the lower facial region.