Abstract :
Human tongue muscles exhibit remarkable neuromuscular compartmentalization, enabling rapid, adaptable, and precise movement essential for speech production and other fine motor tasks. We performed a review to evaluate structural and functional evidence of compartmentalization and its clinical implications. Following PRISMA 2020 guidelines, a comprehensive search of 32 uploaded sources was conducted, screening for studies on human tongue muscle anatomy, physiology, and neuromuscular control using imaging, histology, or electrophysiology. Seventeen studies met inclusion criteria, encompassing experimental, observational, cross?sectional, imaging, and histological methodologies. Findings consistently documented discrete compartments—ranging from approximately four to nearly 100 per muscle—supported by motor endplate mapping, regional fiber typing, and somatotopic organization within cortical and hypoglossal regions. Tagged MRI, functional MRI, diffusion imaging, and histological approaches confirmed independent or synergistic activation patterns. Pathological conditions such as obstructive sleep apnea and post?glossectomy demonstrated en bloc movement, contrasting with the fine, compartment?based control in healthy individuals. Neural findings indicated somatotopic hypoglossal organization and motor unit specialization, with potential translational relevance to neuromuscular therapies. This nuanced understanding may guide clinicians in customizing treatment approaches, improving rehabilitation outcomes, and advancing research on sensorimotor integration in complex orofacial functions.
Keyword :
Tongue, Neuromuscular junction, Motor Control, Magnetic resonance imaging, Speech