An Evaluation of Masseter Muscle Anatomy in Different Facial Patterns Using Magnetic Resonance Imaging: A Comparative Study

Abstract

Aim: To study the anatomical variations of masseter muscle in subjects with different facial patterns using MRI as well as assessing the correlation between them.

Methodology: A total of 30 young, healthy subjects in the age group of 20-28 years were selected and divided into 3 groups of 10 each as vertical, average and horizontal growers using lateral cephalograms. In these subjects, various anatomic dimensions of masseter muscle were measured using MRI, in sagittal, axial and coronal views.

Results: The results showed a statistically significant difference between the vertical and horizontal growth patterns (p<0.05), with respect to Masseter muscle distance from anterior and posterior fibres distal to the 1^st molar and orientation of the muscle fibres to the zygomatic arch.

Conclusion: In our study, we noticed that the orientation of muscle fibres is directed more posteriorly and at a more acute angle whereas in horizontal group the fibres are vertically oriented with anterior attachment at the angle of the mandible.