Morphometry of the masseter muscle and topographic location of the masseteric nerve: anatomical study in terms of BTX-A and facial reanimation applications

Abstract

Aims: The aim of this study was to investigate the morphometry of the masseter muscle (MM) and the topography of the masseteric nerve (MN) innervating the MM. Methods: The MM and MN were examined on 18 sides (female: 4, male: 5) of formaldehyde-fixed adult cadavers in the laboratory of Kocaeli University Faculty of Medicine, Department of Anatomy. The MM and its surroundings were exposed by dissection. The morphometric measurements of the MM were obtained using a digital caliper. Tragus and lateral canthus landmarks were used for the location of the motor nerve of the MM. Results: In this study, morphometric measurements of the MM were presented. A statistically significant difference was found between sexes in morphometric measurements related to the height and width of the muscle (p<0.05). MM thickness was measured as 6.47 (6.06-6.50) mm. The median value of the distance between the tragus and lateral canthus was 76.04 (72.36-79.02) mm. Accordingly, the branching point of the MN; the vertical distance from the midpoint of the distance between the tragus and lateral canthus to the nerve was 42.72 (39.09-44.50) mm. Conclusion: We believe that determining the topographic location of the MN using standard anatomical landmarks will make important contributions to both facial reanimation and BTX-A applications.

Keywords

• Masseter muscle
• masseteric nerve
• facial reanimation
• botulinum toxin type A
• masseter muscle hypertrophy

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