MRI-based anatomical and biomechanical characterization of the human masticatory muscles
In brief
MRI measurements show sex differences in 66 of 68 jaw-muscle parameters
In young adults, MRI measurements found sex-specific differences in 66 of 68 masticatory muscle parameters; men generally had larger muscle volumes, lengths, and cross-sectional areas. The study found no significant left-right differences within either sex, offering detailed inputs for sex-specific biomechanical models. Small, unbalanced groups limit how broadly these measurements can serve as reference values.
- Journal
- Frontiers in bioengineering and biotechnology (Q1)
- Published
- 14 September 2026
- Study design
- Cross-sectional study
- Evidence level
- Level 3, Low (CEBM 3b)
- Authors
- Thomas Zöchmeister, Lukas Berger-Maul, Martin Tik, Erik Kornfellner
- PMID
- 42807087
- DOI
- 10.3389/fbioe.2026.1888163
Why clinicians should know about it
- Picked for Anatomy (paper of the day, 30 September 2026): MRI‑based morphometry of human masticatory muscles
Abstract
Biomechanical models of the masticatory muscles quantify the complex force and movement patterns of the masticatory system and are essential for evidence-based diagnosis, treatment planning, and prosthetic care in the craniomandibular region. This study provides comprehensive, sex-specific parameters for assessing the morphology of the masticatory muscles in young adult males and females, based on high-resolution magnetic resonance imaging (MRI) images and semi-automatic three-dimensional (3D) segmentation. Parameters such as volume, length, anatomical cross-sectional area and surface area of the masseter muscle, pterygoid muscle and temporalis muscle are evaluated bilaterally. Their force application points on the skull and mandible are determined using a new center-of-mass-based segmentation method for biomechanical model interpretation. Statistical analysis indicates that 66 of 68 parameters show significant sex-specific differences, mostly with large effect sizes: male participants generally showed higher volumes, lengths, and cross-sectional areas, except for two cross-sectional areas of the superficialis masseter muscle, resulting in higher surface-to-volume ratios in women. Although minor asymmetrical effects are observed, no significant lateral differences are found within each sex, suggesting bilateral symmetry of the masticatory muscles in the study cohort. Comparing volume data with existing literature shows that this study's data generally exceeds historical cadaver measurements but is consistent with recent digital studies, underscoring the influence of age, methodology, and sex-specific differences on the interpretation of morphometric muscle parameters. Overall, this research provides a valuable foundation for the morphometric characterization and sex-specific biomechanical modeling of the masticatory musculature, while also highlighting the limitations of small, unbalanced, and mixed-sex reference groups.
Abstract as published, via PubMed.
For healthcare professionals. The summary is generated by AI from the published abstract, and the evidence level is assigned automatically from the study design on the Oxford CEBM hierarchy. Neither is medical advice. Read the full paper before changing practice.