Diagnostics
Three-Part MRI Morphology of the Human Masseter Muscle: A Part-Dominance Classification
By Okoń A, Landfald IC, Podgórski M and 3 others.
Abstract
Background
A simple MRI-based framework for describing part-specific dominance patterns in the human masseter muscle is lacking. This study aimed to characterize its MRI-visible parts and develop a preliminary part-dominance classification.
Methods
This retrospective cross-sectional study analysed 58 clinical MRI examinations, comprising 116 masseter muscles with complete bilateral visualization. The three MRI-visible parts were identified on T2-weighted 3D coronal source images. Thickness and length were measured using a predefined study procedure, and each muscle was assigned a part-dominance type according to which part was thickest.
Results
Three distinct parts were identified in all 116 muscles. The inferior part was thickest in 81 muscles (69.8%), the coronoid part in 31 (26.7%), and the middle part in 4 (3.4%). The inferior part was also the longest segment.