The aim of this study was to investigate masticatory muscle activity during deliberately performed functional and non-functional oral tasks. Electromyographic (EMG) surface activity was recorded unilaterally from the masseter, anterior temporalis and suprahyoid muscles in 11 subjects (5 men, 6 women; age = 34.6 +/- 10.8 years), who were accurately instructed to perform 30 different oral tasks u...

A rare case of intramuscular hemangioma of the masseter muscle with multiple phleboliths is described, highlighting features evident in plain radiography, ultrasound, and magnetic resonance imaging (MRI). A 21-year-old woman presented with a complaint of swelling of the right masseter muscle. A plain radiograph from the soft tissue of the right cheek showed a large number of round, target-like ...

This case report details the onset of masseter muscle rigidity, elevated creatine kinase levels, and rhabdomyolysis following a sevoflurane mask induction and succinylcholine administration in a 12-year-old boy. The patient had no family or personal history of neuromuscular disease or malignant hyperthermia. Hyperkalemia, metabolic acidosis, and rhabdomyolysis occurred within 75 minutes of mass...

The purpose of the present investigation was to study the relationship between the ultrasonographic thickness of the masseter muscle and the width of the maxillary dental arch. The sample comprised 60 consecutive orthodontic patients (37 females, 23 males), 7-18 years of age with a Class I relationship and minor malocclusion. The thickness of the masseter muscle was measured ultrasonographicall...

At incremental whole muscle lengths, active isometric and passive elastic forces were recorded from the masseter and digastric muscles of anaesthetized miniature pigs (Hanford) weighing 2.0-20.0 kg. Wet muscle mass and maximum tetanic tension values for masseter exceed those for digastric and increase more rapidly with body mass (age). At any body mass, masseter exceeds digastric in the ratio o...

TNFα induces mechanical sensitization of rat masseter muscle nociceptors, which takes 2-3 h to manifest and is mediated through activation of P55 and P75 receptors. This study was undertaken to determine whether TNFα induces nociceptor mechanical sensitization through the release of other algogenic substances such as glutamate, prostaglandin E(2) (PGE(2)), and/or nerve growth factor (NGF), whic...

The temporalis, masseter, and depressor muscles of fifteen normal children were studied electromyographically to determine their activities during the position of resting tonus, during various movements of the mandible, and during the act of swallowing. Analysis of our results led to the following conclusions: 1. Resting tonus of the mandible does not depend on neuromuscular activity in the thr...

Electromyographic (EMG) activity versus bite force was studied during a gradually increased isometric contraction up to maximal effort for patients with painful masseter muscles and referents. The masseter muscle, the anterior temporal muscle and the descending part of the trapezius muscle were chosen for the recordings. Bite force was registered with a bite force sensor placed between the firs...

Pain in masticatory muscles is among the most prominent symptoms of temperomandibular disorders (TMDs) that have diverse and complex etiology. A common complaint of TMD is that unilateral pain of craniofacial muscle can cause a widespread of bilateral pain sensation, although the underlying mechanism remains unknown. To investigate whether unilateral inflammation of masseter muscle can cause a ...

There is a paucity of information regarding the anatomy and muscle fiber phenotype of the masseter. The objective of this study was to characterize the distribution of each myosin heavy-chain (MyHC) isoform within different anatomical regions of male and female mouse masseters. Masseters from male and female CD-1 mice (2-4 months old) were examined for description of the anatomical partitioning...