The volume of muscles of mastication in patients receiving mandibular contouring surgery: a comparative study

Purpose: As the management of prominent mandibular angle and masseter muscle hypertrophy becomes increasingly popular, proper understanding of the volumetric component of the related structures becomes important but is currently lacking. Materials and methods: Three-dimensional computed tomographic (CT) scans of 18 female and eight male adult patients with square-face appearance were used for volumetric measurement of the osseous hemi-mandible, masseter, medial and lateral pterygoid muscles. CT scans of 28 female and 17 male adult patients without square-face appearance were selected from the imaging laboratory archive to serve as controls. Results: Compared with the sex-matched controls, the square-faced patients had significantly higher volume of the osseous hemi-mandible as well as the masseter and medial pterygoid muscles. There was no significant difference in the volume of the lateral pterygoid muscle between the two groups. This study confirms a significantly greater volume in the osseous mandible and masseter muscle in patients complaining of square-face appearance. The implication of this information on treatment is discussed.