Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Temporal Muscle”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,045 records · Page 58Linked to original sources
PubMed1991

Activity index and isometric contraction velocity of human jaw muscles.

To determine the relative contribution of the masseter and anterior temporalis muscles to global isometric bite force, activity indices were constructed on the basis of the peak mean voltage (microV) and the integrated voltage (microV.s) of bipolar surface electromyograms obtained during brief maximum voluntary teeth clenching (MVC). The index that was based on integrated myoelectrical activity showed that the masseter muscle contributed the major part of the isometric MVC force. The index that was based on instantaneous peak myoelectrical activity also showed that activity in the masseter muscle predominated over that in the anterior temporalis muscle. In addition, the latter index showed a negative linear association with the initial (0-50% MVC) isometric contraction velocities of the masseter and anterior temporalis muscles. Both indices appear to be promising clinical diagnostic tools.

Action Potentials↗
PubMed2005

Surface EMG of jaw-elevator muscles and chewing pattern in complete denture wearers.

The aim of this study was to investigate the adaptation process of masticatory patterns to a new complete denture in edentulous subjects. For this purpose, muscle activity and kinematic parameters of the chewing pattern were simultaneously assessed in seven patients with complete maxillary and mandibular denture. The patients were analysed (i) with the old denture, (ii) with the new denture at the delivery, (iii) after 1 month and (iv) after 3 months from the delivery of the new denture. Surface electromyographic (EMG) signals were recorded from the masseter and temporalis anterior muscles of both sides and jaw movements were tracked measuring the motion of a tiny magnet attached at the lower inter-incisor point. The subjects were asked to chew a bolus on the right and left side. At the delivery of the new denture, peak EMG amplitude of the masseter of the side of the bolus was lower than with the old denture and the masseters of the two sides showed the same intensity of EMG activity, contrary to the case with the old denture. EMG amplitude and asymmetry of the two masseter activities returned as with the old denture in 3 months. The EMG activity in the temporalis anterior was larger with the old denture than in the other conditions. The chewing cycle width and lateral excursion decreased at the delivery of the new denture and recovered after 3 months.

Adaptation, Physiological↗
PubMed1991

EMG activity in pericranial muscles during postural variation and mental activity in healthy volunteers and patients with chronic tension type headache.

EMG activity was recorded over frontalis, temporalis and trapezius muscles in a supine position, a standing position and during a mental task in 32 female patients suffering from chronic tension-type headache and in 20 healthy volunteers. Measurements in patients were made before and after biofeedback therapy. All EMG levels were on average significantly higher in patients than in controls. 62.5% of patients had at least one abnormal EMG level, but only 34% were beyond the normal range, if 1 muscle and 1 recording condition was considered. EMG levels were not correlated with headache severity, anxiety or response to biofeedback treatment. It is therefore suggested that pericranial EMG activity is not pathogenetic in chronic tension type headache, but merely one of several pathophysiologic changes, that are produced by a central dysfunction.

Adolescent↗
PubMed1994

Effects of tizanidine administration on exteroceptive suppression of the temporalis muscle in patients with chronic tension-type headache.

The aim of this study was to clarify the changes of inhibitory interneuronal activity in patients with chronic tension-type headache with disorder of pericranial muscle after treatment, and the pharmacological mechanisms of tizanidine--an alpha 2 adrenergic agonist. The effects of tizanidine on exteroceptive suppression (ES) of the temporalis muscle were examined in eighteen patients with chronic tension-type headache with disorder of pericranial muscles, before and two weeks after the administration of tizanidine. The left mental nerve was stimulated, under the maximal voluntary contraction of the temporalis muscles. Two types of stimulation were used: weak stimulation with four times the sensory threshold, and strong stimulation with 10 times the sensory threshold. The rectified electromyographic activity was recorded from the right temporalis muscle. ES2 produced by four times the sensory threshold was lengthened after tizanidine administration. This fact suggests that tizanidine improves the inhibitory function in the central nervous system, and then relieves headache. However, ES produced by 10 times the sensory threshold did not change. This suggests that the effect of tizanidine may be relatively mild. The interneurones mediating ES2 may be modified by the alpha 2 agonist.

Clonidine↗
PubMed1991

Temporalis and masseter muscle activity in patients with anterior open bite and craniomandibular disorders.

Activity in temporalis and masseter muscles, and traits of facial morphology and occlusal stability were studied in 22 patients (19 women, 3 men; 15-45 yr of age) with anterior open bite and symptoms and signs of craniomandibular disorders. Facial morphology was assessed by profile radiographs, occlusal stability by tooth contacts, and craniomandibular function by clinical and radiological examination. Electromyographic activity was recorded by surface electrodes after primary treatment with a reflex-releasing, stabilizing splint. Maximal voluntary contraction was reduced compared to reference values, particularly in subjects with muscular affection, but maximal activity increased significantly when biting on the splint. Maximal voluntary contraction was positively correlated to molar contact and negatively to anterior face height, mandibular inclination, vertical jaw relation and gonial angle. Relative loading of the muscles was markedly increased during resting posture. It was concluded that reduced occlusal stability and long-face morphology were associated with weak elevator muscle activity with disposition overload and tenderness. The results also indicated that increase of occlusal stability might lead to increased muscle strength and possibly reduce risk of physical strain.

Adolescent↗
PubMed2004

Human jaw muscle strength and size in relation to limb muscle strength and size.

The aim of the present study was to investigate to what extent general factors (e.g. genotype, hormones) and factors at the craniofacial level (e.g. craniofacial size, jaw muscle architecture) contribute to the size and strength of the jaw muscles. A strong relationship of jaw muscle size and strength with that of other muscles would argue for general influences, whereas a weak relationship would argue for craniofacial influences. In 121 adult individuals, moments of maximal bite force, arm flexion force and leg extension force were measured. In addition, thicknesses of jaw muscles, arm flexor muscles and leg extensor muscles were measured using ultrasound. Relationships were assessed by using a principal component analysis. In females, one component was found in which all force moments were represented. Bite force moment, however, loaded very low. In males, two components were found. One component loaded for arm flexion and leg extension moments, the other loaded for bite force moments. In both females and males, only one component was found for the muscle thicknesses in which all muscle groups loaded similarly. It was concluded that the size of the jaw muscles was significantly related to the size of the limb muscles, suggesting that they were both subject to the same general influences. Maximal voluntary bite force moments were not significantly related to the moments of the arm flexion and leg extension forces, suggesting that besides the general influence on the muscle size, variation in bite force moment was also influenced by local variables, such as craniofacial morphology.

Adolescent↗
PubMed2006

No effect of experimental occlusal interferences on pressure pain thresholds of the masseter and temporalis muscles in healthy women.

It has been suggested that occlusal interferences may lead to pain and tenderness of the masticatory muscles. Tender jaw muscles are more sensitive to pressure pain, as assessed by means of pressure algometry. We tested the effects of occlusal interferences on the pressure pain threshold of the jaw muscles by means of a double-blind randomized crossover experiment carried out on 11 young healthy females. Golden strips were glued either to an occlusal contact area (active interference) or to the vestibular surface of the same tooth (dummy interference) and left for 8 d each. Pressure pain thresholds of the masseter and anterior temporalis muscles were assessed under interference-free, dummy-interference and active-interference conditions. The results indicated that the application of an active occlusal interference, as used in this study, did not influence significantly the pressure pain thresholds of these muscles in healthy individuals.

Adult↗
PubMed1986

Correlation between histochemistry and muscle activity of jaw muscles in cats.

Studies on limb muscles of mammals indicate that the pattern of electromyographic (EMG) activity reflects the histochemical profile of the muscle. This relationship suggests that EMG activity may permit a prediction of certain morphological characteristics of the muscle being studied. In this study numerical descriptors of EMG activity of the masticatory muscles of cats are correlated with the distribution of fiber types, as well as with fiber and fascicle areas, to test the extent to which EMG can be used to predict regional morphology. The results show that the level of EMG activity and its duration have a significant positive correlation with the percentage of slow- and fast-twitch fatigue-resistant fibers and a significant negative correlation with the percentage of fast-twitch fatigable fibers and the ratio of fast-twitch fatigable to fast-twitch fatigue-resistant, plus slow fibers. No correlation was found between activity and fiber cross-sectional area; the descriptors showing significant correlation vary with the hardness of the food. Thus the level of EMG activity and its duration seemingly do provide an indicator of the relative difference in fiber distribution among muscles in a species.

Adenosine Triphosphatases↗
PubMed2000

EMG activities of two heads of the human lateral pterygoid muscle in relation to mandibular condyle movement and biting force.

Electromyographic (EMG) activities of the superior (SUP) and inferior heads (INF) of the lateral pterygoid muscle (LPT) were recorded in humans during voluntary stepwise changes in biting force and jaw position that were adopted to exclude the effects of acceleration and velocity of jaw movements on the muscle activity. The SUP behaved like a jaw-closing muscle and showed characteristic activity in relation to the biting force. It showed a considerable amount of background activity (5-32% of the maximum) even in the intercuspal position without teeth clenching and reached a nearly maximum activity at relatively lower biting-force levels than the jaw-closing muscles during increment of the biting force. Stretch reflexes were found in the SUP, the function of which could be to stabilize the condyle against the biting force that pulls the condyle posteriorly. This notion was verified by examining the biomechanics on the temporomandibular joint. The complex movements of the mandibular condyle in a sagittal plane were decomposed into displacement in the anteroposterior direction (Ac) and angle of rotation (RAc) around a kinesiological specific point on the condyle. In relation to Ac, each head of the LPT showed quite a similar behavior to each other in all types of jaw movements across all subjects. Working ranges of the muscle activities were almost constant (Ac <3 mm for the SUP and Ac >3 mm for the INF). The amount of EMG activity of the SUP changed in inverse proportion to Ac showing a hyperbola-like relation, whereas that of the INF changed rather linearly. The EMG amplitude of the SUP showed a quasilinear inverse relation with RAc in the hinge movement during which the condyle rotated with no movement in the anteroposterior direction. This finding suggests that the SUP controls the angular relationship between the articular disk and the condyle. On the other hand, the position of the disk in relation to the maxilla, not to the condyle, is controlled indirectly by the INF because the disk is attached to the condyle by tendinous ligaments.

Adult↗
PubMed1981

Masticatory muscle silent periods in patients with MPD syndrome before and after treatment.

Masticatory muscle silent periods were compared in normal subjects and in patients with MPD syndrome before and after a variety of psychological, physiological, and pharmacological forms of therapy. All patients initially showed prolonged silent periods in one or more of the muscles. There was a direct relationship between prolongation and severity of symptoms. The temporalis (90.9%) and masseter (54.5%) were most frequently involved. In almost all instances the silent periods returned to the normal range following treatment.

Adult↗
PubMed2006

The immediate effect of changing mandibular position on the EMG activity of the masseter, temporalis, sternocleidomastoid, and trapezius muscles.

This study investigated the immediate effect of changing mandibular position on the electromyographic (EMG) activity of the masseter (MS), temporalis (TM), sternocleidomastoid (SCM) and trapezius (TR) muscles. Thirty-three (33) asymptomatic subjects (16 males and 17 females), ages 23 to 52 were selected. Surface EMG recordings were obtained for all muscles bilaterally with the mandible in a relaxed open position (relaxed) and during maximal voluntary clenching (fullbite) for the following: a non-repositioning appliance (NONREPOS) and repositioning appliance (REPOS). REPOS significantly reduced EMG activity of all muscles bilaterally during fullbite. During relaxation, reduction in EMG activity was only found for TR bilaterally. NONREPOS decreased the EMG activity bilaterally for TM and TR and unilaterally (left) for MS and SCM during fullbite. During relaxation, NONREPOS decreased muscle activity bilaterally for TR and SCM. A unilateral reduction was found for TM (right). These findings suggest that immediate alterations in mandibular position affect the cranio-cervical system. Both mandibular positions tested lowered the EMG activity of masticatory and cervical muscles in the relaxed and fullbite positions. The trapezius muscle was the most responsive to alterations in mandibular position.

Adult↗
PubMed1991

Electromyography of masticatory muscles in craniomandibular disorders.

Patients presenting to the otolaryngologist with complaints such as otalgia, dizziness, tinnitus, or fullness in the ear may be experiencing the effects of craniomandibular disorders. These disorders can involve dysfunction in the delicate interrelationship of the skull, mandible, cervical vertebrae, and neuromuscular apparatus and can present as myofacial pain. Electromyographic recordings using surface electrodes were made bilaterally on the masseter, anterior temporalis, and digastric muscles in 641 craniomandibular patients, before and after transcutaneous electrical neural stimulation, at their initial presentation and following the insertion of mandibular orthopedic appliances. In the presenting patient, muscle-resting levels significantly decreased from hyperactive levels with transcutaneous electrical neural stimulation therapy. The creation of a new occlusal position with an orthotic appliance was found to correlate with a significant reduction in otolaryngologic symptoms as well as an increase in maximum muscle activity in function and coordination of muscle groups during mandibular movement. Thus, clinical electromyographic studies are an important aid in the treatment of craniomandibular disorders.

Electromyography↗
PubMed1994

Differentiation of histochemical properties of masticatory muscles in Bovidae and Cervidae (Artiodactyla).

We analyzed the masticatory muscles (masseter, temporal, medial pterygoid and lateral pterygoid muscles) of Bovidae and Cervidae (Artiodactyla) for the histochemical characteristics of their fiber types. Analysis of muscle fiber types in the present study was based on the staining reaction for SDH, Sudan black B, alpha-GPDH, and myosin-ATPase after alkaline preincubations. Histochemical properties were found to contribute to masticatory function, including a slow-twitch fatigue resistant activity derived from the high percentage of red fibers, in spite of the differences in the distributions of fiber types in three portions (superficial, medial and profound portions) of each masticatory muscle. These results indicate a correlation between the histochemical profiles of individual masticatory muscles in these species and their functions during jaw movements.

Animals↗
PubMed1986

Amianthoid fibres in muscle tissue associated with temporomandibular joint ankylosis.

The masseter and temporalis muscles were studied ultrastructurally in 3 patients having extra and intra-articular ankylosis of the TMJ. Amianthoid fibres (thick collagen fibres) varying from 280-430 nm in diameter were found in the connective tissue of both muscles. These fibres appeared to form by fusion of collagen fibrils of normal thickness rather than representing an active dynamic process. The presence of amianthoid fibres in these muscles may account for the restricted mouth opening associated with TMJ ankylosis and could be of some value in future management of this condition.

Adult↗
PubMed1996

Functional reorganization of the partially denervated hindlimb extensor and flexor muscle in rat.

In view of the neuromuscular system plasticity the functional changes induced by partial denervation are presented. The long-term effects of partial denervation of postural (soleus-SOL) or flexor (extensor digitorum longus-EDL) muscles on their EMG activity were studied in rats. The activity per motor unit was significantly higher both in the partially denervated SOL and EDL muscles. During standing or walking the EMG activity pattern of the partially denervated SOL muscle was similar to normal, while the partially denervated EDL muscle during standing exhibited abnormal tonic activity, and during locomotion its burst duration was strongly correlated to the step cycle duration. Thus, partial denervation led to an overall increase of activity of the remaining motor units in both SOL and EDL muscles, while the temporal pattern of muscle activity during locomotion was drastically altered in EDL muscle only, what indicates that partial denervation influenced the postural activity less than the phasic one.

Animals↗
PubMed1999

Differential response of rat skeletal muscle glycogen metabolism to testosterone and estradiol.

Although reports on sex steroids have implicated them as promoting protein synthesis and also providing extra strength to the skeletal muscle, it remains unclear whether sex steroids affect glycogen metabolism to provide energy for skeletal muscle functions, since glycogen metabolism is one of the pathways that provides energy for the skeletal muscle contraction and relaxation cycle. The purpose of the current study was to show that testosterone and estradiol act differentially on skeletal muscles from different regions, differentially with reference to glycogen metabolism. To study this hypothesis, healthy mature male Wistar rats (90-120 days of age, weighing about 180-200 g) were castrated (a bilateral orchidectomy was performed to test the significance of skeletal muscle glycogen metabolism in the absence of testosterone). One group of castrated rats was supplemented with testosterone (100 microg/100 g body weight, i.m., for 30 days from day 31 postcastration onwards). To test whether estradiol has any effect on male skeletal muscle glycogen metabolism 17beta-estradiol (5 microg/100 g body weight, i.m., for 30 days from day 31 postcastration onwards) was administered to orchidectomized rats. To test whether these sex steroids have any differential effect on skeletal muscles from different regions, skeletal muscles from the temporal region (temporalis), muscle of mastication (masseter), forearm muscle (triceps and biceps), thigh muscle (vastus lateralis and gracilis), and calf muscle (gastrocnemius and soleus) were considered. Castration enhanced blood glucose levels and decreased glycogen stores in skeletal muscle from head, jaw, forearm, thigh, and leg regions. This was accompanied by diminished activity of glycogen synthetase and enhanced activity of muscle phosphorylase. Following testosterone supplementation to castrated rats, a normal pattern of all these parameters was maintained. Estradiol administration to castrated rats did not bring about any significant alteration in any of the parameters. The data obtained suggest a stimulatory effect of testosterone on skeletal muscle glycogenesis and an inhibitory effect on glycogenolysis. Estradiol did not play any significant role in the skeletal muscle glycogen metabolism of male rats.

Animals↗
PubMedDate not supplied

Temporomandibular region in the Franceschetti's Syndrome. Anatomical study.

Franceschetti's syndrome is a rare, non-fatal, hereditary malformation, usually bilateral, which symmetrically affects orbits, mandible and ear. The authors propose an anatomical description of the temporomandibular region after the dissection of a newborn baby suffering from Franceschetti's Syndrome, dead soon after the birth. A discussion on the different etiopathogenical theories is made. The authors conclude that an alteration of the development of nerve trigeminal branches is the cause of the malformations.

Ear Canal↗