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Functional Compartmentalization of the Human Superficial Masseter Muscle

Some muscles have demonstrated a differential recruitment of their motor units in relation to their location and the nature of the motor task performed; this involves functional compartmentalization. There is little evidence that demonstrates the presence of a compartmentalization of the superficial...

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Autores principales: Guzmán-Venegas, Rodrigo A., Biotti Picand, Jorge L., de la Rosa, Francisco J. Berral
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4334967/
https://www.ncbi.nlm.nih.gov/pubmed/25692977
http://dx.doi.org/10.1371/journal.pone.0116923
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author Guzmán-Venegas, Rodrigo A.
Biotti Picand, Jorge L.
de la Rosa, Francisco J. Berral
author_facet Guzmán-Venegas, Rodrigo A.
Biotti Picand, Jorge L.
de la Rosa, Francisco J. Berral
author_sort Guzmán-Venegas, Rodrigo A.
collection PubMed
description Some muscles have demonstrated a differential recruitment of their motor units in relation to their location and the nature of the motor task performed; this involves functional compartmentalization. There is little evidence that demonstrates the presence of a compartmentalization of the superficial masseter muscle during biting. The aim of this study was to describe the topographic distribution of the activity of the superficial masseter (SM) muscle’s motor units using high-density surface electromyography (EMGs) at different bite force levels. Twenty healthy natural dentate participants (men: 4; women: 16; age 20±2 years; mass: 60±12 kg, height: 163±7 cm) were selected from 316 volunteers and included in this study. Using a gnathodynamometer, bites from 20 to 100% maximum voluntary bite force (MVBF) were randomly requested. Using a two-dimensional grid (four columns, six electrodes) located on the dominant SM, EMGs in the anterior, middle-anterior, middle-posterior and posterior portions were simultaneously recorded. In bite ranges from 20 to 60% MVBF, the EMG activity was higher in the anterior than in the posterior portion (p-value = 0.001).The center of mass of the EMG activity was displaced towards the posterior part when bite force increased (p-value = 0.001). The topographic distribution of EMGs was more homogeneous at high levels of MVBF (p-value = 0.001). The results of this study show that the superficial masseter is organized into three functional compartments: an anterior, a middle and a posterior compartment. However, this compartmentalization is only seen at low levels of bite force (20–60% MVBF).
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spelling pubmed-43349672015-02-24 Functional Compartmentalization of the Human Superficial Masseter Muscle Guzmán-Venegas, Rodrigo A. Biotti Picand, Jorge L. de la Rosa, Francisco J. Berral PLoS One Research Article Some muscles have demonstrated a differential recruitment of their motor units in relation to their location and the nature of the motor task performed; this involves functional compartmentalization. There is little evidence that demonstrates the presence of a compartmentalization of the superficial masseter muscle during biting. The aim of this study was to describe the topographic distribution of the activity of the superficial masseter (SM) muscle’s motor units using high-density surface electromyography (EMGs) at different bite force levels. Twenty healthy natural dentate participants (men: 4; women: 16; age 20±2 years; mass: 60±12 kg, height: 163±7 cm) were selected from 316 volunteers and included in this study. Using a gnathodynamometer, bites from 20 to 100% maximum voluntary bite force (MVBF) were randomly requested. Using a two-dimensional grid (four columns, six electrodes) located on the dominant SM, EMGs in the anterior, middle-anterior, middle-posterior and posterior portions were simultaneously recorded. In bite ranges from 20 to 60% MVBF, the EMG activity was higher in the anterior than in the posterior portion (p-value = 0.001).The center of mass of the EMG activity was displaced towards the posterior part when bite force increased (p-value = 0.001). The topographic distribution of EMGs was more homogeneous at high levels of MVBF (p-value = 0.001). The results of this study show that the superficial masseter is organized into three functional compartments: an anterior, a middle and a posterior compartment. However, this compartmentalization is only seen at low levels of bite force (20–60% MVBF). Public Library of Science 2015-02-18 /pmc/articles/PMC4334967/ /pubmed/25692977 http://dx.doi.org/10.1371/journal.pone.0116923 Text en © 2015 Guzmán-Venegas et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Guzmán-Venegas, Rodrigo A.
Biotti Picand, Jorge L.
de la Rosa, Francisco J. Berral
Functional Compartmentalization of the Human Superficial Masseter Muscle
title Functional Compartmentalization of the Human Superficial Masseter Muscle
title_full Functional Compartmentalization of the Human Superficial Masseter Muscle
title_fullStr Functional Compartmentalization of the Human Superficial Masseter Muscle
title_full_unstemmed Functional Compartmentalization of the Human Superficial Masseter Muscle
title_short Functional Compartmentalization of the Human Superficial Masseter Muscle
title_sort functional compartmentalization of the human superficial masseter muscle
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4334967/
https://www.ncbi.nlm.nih.gov/pubmed/25692977
http://dx.doi.org/10.1371/journal.pone.0116923
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