PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Pterygoid Muscles”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

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

At least 73 records · Page 4Linked to original sources
PubMed1993

Parasagittal magnetic resonance imaging of the lateral pterygoid muscle: a preliminary study.

Ten anatomic territories, including both lateral pterygoid muscle and temporomandibular joint heads, were explored with magnetic resonance imaging in subjects with no dysfunctional disorders. The sequence used was one of inversion-recovery, supplemented with image contrast reversal for better visualization. The muscles were observed in the resting position and in dynamic relation. Slice plane definition provided information on the anatomic variations of the superior head and on the muscle-articular junction, in particular on the fascicular aspect of the superior lateral pterygoid muscle and on the differentiation between condyle insertions under effort. The choice of technique and the results are discussed. Avenues are opened for the exploration of muscles utilizing magnetic resonance imaging.

Adult↗
PubMed2001

A method for standardizing jaw displacements in the horizontal plane while recording single motor unit activity in the human lateral pterygoid muscle.

The normal function of the lateral pterygoid muscle is not well understood although this muscle is thought to play an important role in the control of jaw and jaw-joint function and is implicated in temporomandibular disorders (TMD). The lack of a validated method for standardization of jaw movement in studies of lateral pterygoid function has contributed to the lack of understanding of the normal function of this muscle. An improved understanding of normal function will allow valid comparisons to be made with TMD patients in order to identify whether purported differences in activity actually exist. This paper describes a methodology for standardizing command jaw movements in the horizontal plane, together with reliable recordings of single-motor-unit (SMU) activity. In six human participants, jaw movements were standardized by having participants track a linear bank of light-emitting diodes (LEDs) aligned on a monitor displaying the mid-incisor point (MIPT). In all participants, the MIPT target (i.e. an illuminated LED) could be tracked, according to a pre-determined criterion, during single- and multiple-step displacements at different rates (1.3--6.5 mm/s at MIPT) and magnitudes (0.65--12 mm) of movement. SMU activity from the superior (SHLP) or inferior (IHLP) head of the lateral pterygoid muscle could be reliably discriminated during repeated trials of these defined tasks. This methodology establishes a reliable technique for characterizing the firing properties of SMUs within the lateral pterygoid, and has implications for analogous studies in other jaw muscles.

Adult↗
PubMed1989

[Macro-anatomical studies on the palpability of the lateral inferior pterygoid muscle].

In order to diagnose muscular dysfunction associated with the lower pterygoid muscle common intraoral palpation techniques require this muscle to be touched with the fingertip or a probing instrument. A macro-anatomical study using heads of humans has been done to demonstrate morphometrically the origin of the M. pterygoideus lateralis inferior in relation to neighbouring structures. In a majority of cases intraoral palpation of the lower pterygoid muscle is probably impossible.

Humans↗
PubMed1991

The lateral pterygoid muscle: some anatomical, physiological and clinical considerations.

The lateral pterygoid muscles make a unique contribution to jaw movement control by virtue of their attachment to temporomandibular disc and condyle. Their highly specialized function is reflected in their extrafusal muscle fibre composition and the paucity of muscle spindles to provide proprioceptive feedback. It is likely (studies in progress) that their histochemical spindle intrafusal fibre composition is also unique. The superior and inferior portions of the muscle have defined functional roles. The superior portion primarily contributes to the apposition of disc, condyle and eminence in jaw closing, whilst the lateral portion primarily contributes to jaw opening. In this review, possible control mechanisms for this muscle are proposed. As well, the role of the superior head in influencing rotation and translation of disc and condyle and the relationship with internal derangement and temporomandibular dysfunction is considered.

Electromyography↗
PubMed1985

The control of condylar growth: an experimental evaluation of the role of the lateral pterygoid muscle.

The present study used 21 male albino rats to test the hypothesis that lateral pterygoid traction regulates the growth of the mandibular condyle. The condyles, the rami, and the top of each glenoid fossa were marked with metallic implants, and, following bilateral section of the condylar neck, one lateral pterygoid muscle was extirpated. On the basis of the literal details of Petrovic's cybernetic model, it was assumed that the continued forward growth of the midface and the backward translation of the glenoid fossa would combine to produce a progressive disturbance in the buccal occlusion that would, in turn, generate a reflex contraction of the remaining lateral pterygoid muscle. Initially, however, growth of the isolated condyles would have little impact on the spatial position of the rest of the mandible. As a result, the condyles on the side with the intact lateral pterygoid should grow for a time at a maximal, open-circuit rate, whereas the experimental condyle, deprived of all muscle traction, should show only a minimal "commanded" rate of growth. The serial change in the position of the condylar and ramal implants was assessed cephalometrically for 6 weeks, and between-sides differences were analyzed by randomized block analysis of variance. The presence or absence of the lateral pterygoid muscle had no significant effect on the anteroposterior position of the condylar implants and only a slight, transitory effect on their vertical position. The translation of the ramal implants, however, was greatly affected by the condylotomy. On both control and experimental sides, the mandible collapsed upward and backward until contact between the growing condyle and ramus had been achieved, whereupon a downward and forward pattern of translatory growth was re-established. Although it could not be shown that lateral pterygoid traction per se is a significant factor in the growth of isolated condyles, it was concluded that the condyle is vitally important to the translatory growth of the mandible as a whole. On the basis of these data and the current literature, a simple hypothesis was advanced for the control of condylar growth by the ongoing pattern of functional loading and for the role of this growth in the normal downward and forward displacement of the rest of the mandible.

Animals↗
PubMed1984

Temporomandibular joint dysfunction: a theory based upon electromyographic studies of the lateral pterygoid muscle.

Electromyographic investigations into the function of the two individual heads of the lateral pterygoid muscle in normal persons are compared with patients suffering the pain of temporomandibular joint dysfunction and those with painless clicks. The results indicate that the lower head of the lateral pterygoid muscle, normally active only when depressing, protruding and deviating the mandible, becomes active on closing and clenching in patients suffering pain. Patients with painless clicks behave as normals. These results are discussed and a theory is presented which suggests that temporomandibular joint dysfunction has a simple pathological basis.

Adult↗
PubMed1987

Lateral pterygoid muscle activity in mandibular retrognathism and response to mandibular advancement surgery.

Electromyographic patterns of muscle activity were recorded in 11 patients with mandibular retrognathism and compared with ten normal subjects. Categorization of facial morphology was based on standard cephalometric data. Seven patients in the retrognathic group have been studied 1 year after mandibular-lengthening surgery. A computer-based data acquisition and analysis system with a Selspot movement monitoring system was used to record and quantify simultaneously both mandibular movement patterns and associated electromyographic data. Of particular interest was the pattern of activity for the lateral pterygoid muscles of all patients in the retrognathic group compared with controls. Both the ipsilateral and contralateral lateral pterygoids contracted during either right or left lateral excursions for eight of the 11 patients in the retrognathic group compared to aphasic activity during this movement as expected in the control group. However, all seven of the patients tested 1 year after mandibular lengthening demonstrated normal aphasic firing patterns of the lateral pterygoid muscles (inferior belly) during right and left lateral excursions. The retrognathic group of patients also demonstrated abnormal recruitment patterns of the lateral pterygoid muscles during border movements of the mandible in the preoperative stage. Recruitment patterns approached normal levels after mandibular advancement surgery. The number of patients studied did not permit accurate statistical analysis. However, a trend is apparent that demonstrates previously unreported abnormal activity patterns of the lateral pterygoid muscles and an adaptive response of these muscles to orthognathic surgery.

Adult↗
PubMed1991

[Histological studies of the morphological relationship of the lateral pterygoid muscle to the articular disk in the human temporomandibular joint].

The biomechanical process which lead to the development of cracking sounds in the temporomandibular joints have received contradictory treatment in the literature. Most of the authors regard consider the cracking sounds to be caused by mechanical friction produced in translational movements of the condylus. According to this hypothesis the discus articularis which is dislocated in an anterior direction active pulling of the lateral pterygoid muscle, is regarded as being a mechanical obstacle. The morphological relationships however, between the lateral pterygoid muscle and the discus articularis are unclear. Our histomorphological investigations of 16 human temporomandibular joint samples from fresh cadavers of victims of accidental death revealed evidence that in the majority of cases a tendon connected the upper head of the lateral pterygoid muscle with the discus articularis. This would suggest that an anterior dislocation of the discus, resulting from an active pulling movement of the lateral pterygoid muscle, cannot be ruled out as a possible morphological cause for cracking sounds.

Adolescent↗
PubMed2006

Morphology of the lateral pterygoid muscle associated to the mandibular condyle in the human prenatal stage.

The lateral pterygoid muscle (LPM) inserts at the condyle and the articular disc and plays a central role in mandibular movement via the Temporomandibular Articular Complex. The aim of this study was to examine the association between the morphology of LPM muscular fascicles and the degree of mineralization of the mandibular condyle in the prenatal stage employing structural, ultrastructural and microanalytical evaluation. Sixteen human fetuses at 11-37 weeks of gestation, with no apparent pathology and resulting from spontaneous abortions, were included in the study. Samples from lateral pterygoid muscle and the mandibular condyle were processed for light microscopy and electron microscopy and microanalysis. Desmin immunolabeling (dilution 1: 25 Dako) and alpha sarcomeric actin immunolabeling (dilution 1:50 Dako) employing the avidin-biotin system were used in paraffin embedded samples. Contralateral samples were examine by transmission electron microscopy. Four condyles (at 17-21 weeks of gestation) were used to measure the relative content of calcium and phosphorous employing the X-ray diffraction microanalytical technique. At 11-16 weeks of gestation, the LPM was composed of secondary myotubes associated to satellite cells and nerve fibers. At 18 weeks, the muscle exhibited multiple compact fascicles and the condyle showed a thin, external, subperiostal mineralized layer with few central bone spicules. At 20 weeks, at the site of insertion of the LPM, the bone trabeculae of the condyle contained an electrondense matrix with abundant mineralization nuclei. At 17-21 weeks of gestation no significant variations in the contents of phosphorous and calcium were observed. At 24 weeks, transmission electron calcium and microscopy studies revealed a marked increase in the functional units of the muscle fascicles. Also, at this age muscle fibers exhibited differences in the expression of desmin and alpha sarcomeric actin. At 37 weeks the muscle became multipennate in appearance, exhibiting a more complex organization than younger fetuses. Alpha sarcomeric actin labeling became light with age. This results suggest that between 16 and 22 weeks of gestation the differentiation and maturation process of the muscle fibers precedes and prevails over the development and mineralization process from mandibular condyle. The rudimentary performance of the prenatal LPM would be one of the factors that regulate the process of ossification at the level of the mandibular condyle. The rate of ossification would increase starting from 22 of gestation week.

Actins↗
PubMed1994

Histologic characteristics of the lateral pterygoid muscle insertion to the temporomandibular joint.

This study used low-power light microscopy to examine the histologic organization of the lateral pterygoid muscle interface with the temporomandibular joint. The sample included parasagittal sections of 20 intact temporomandibular joints from young adults (mean age 26.2 years) at autopsy. The lateral pterygoid muscle showed no consistent divisions into separate anatomic muscle heads at the insertion. The muscle fibers attached to the pterygoid fovea of the condyle immediately inferior to the articular surface in all cases. Some additional fibers inserted superiorly into the more anterior part of the articular disc in a minority of cases (31%). Fibers inserting into the disc represented only 2.4% to 6% of the total superior-inferior length of the muscle insertion. It is hypothesized that the muscular force exerted by these few fibers inserting into the disc would not be sufficient to displace the disc anteriorly to the condyle. There were two histologic types of insertion of the lateral pterygoid muscle to the condyle. The superior part of the insertion was characterized by an identifiable tendon inserting through fibrocartilage. In the inferior part of the insertion, the muscle attached to periosteum without an obvious tendon. The presence of this tendon must be recognized in interpretation of soft tissue temporomandibular joint imaging.

Adolescent↗
PubMed1990

[An electromyographic study of the inferior head of the lateral pterygoid muscle and the anterior belly of the digastric muscle during jaw-opening].

This study investigated the functional roles of the inferior of the lateral pterygoid muscle (LPt) and the anterior belly of the digastric muscle (Da) during jaw-opening, in which EMG activity was simultaneously recorded at the condylar and incisor points. The LPt was found to slide the condyle along the articular tubercles and the Da was moved the incisor region downward-backward for condylar rotation. Therefore, rotation of the condyle and sliding of the mandible downward-forward apparently combined in a coordinated movement. Direct relationships were found between LPt activity and the distance of condylar movement, and between Da activity and the velocity of incisor movement during opening of the mandible. Therefore, the muscles primarily engaged in wide opening movement were mainly the LPt, and for rapid opening, mainly the Da.

Electromyography↗
PubMed1994

The anatomical basis for ultrasonography of the lateral pterygoid muscle and the infratemporal fossa.

The infratemporal fossa and its contents (particularly the pterygoid muscles) is a region difficult to explore, in spite of its importance in odontostomatological pathology. In order to reduce the indications that justify examination by computed tomography and magnetic resonance imaging, for reasons of economy of health, the authors describe by application of orientated anatomical slices the way in which ultrasonography can be performed. Only the posterior approach between the mandible laterally and the mastoid process medially provided consistently adequate exploration of the infratemporal fossa and the pterygoid muscles.

Humans↗
PubMed1975

Clinical kinesthetic experiments on the lateral pterygoid muscle and temporomandibular joint in man.

The possible kinesthetic function of proprioceptors in the lateral pterygoid muscle was clinically assessed after anesthesia of muscle and temporomandibular joint receptors, respectively. A mandibular posture was actively and repetitively produced with an average accuracy of 2.5 mm, while the accuracy decreased by about two-fold after narcotization. It is suggested that muscle spindles in the lateral pterygoid muscle as well as mechanoreceptors in the temporomandibular joint capsule are active in the perception and/or control of mandibular postures.

Adult↗
PubMed1986

Medial pterygoid muscle activity during chewing and clenching.

Specific activity of the human medial pterygoid muscle in relation to jaw movements and occlusion during mastication and clenching tasks is unclear. EMG activity of the medial pterygoid, masseter, anterior, and posterior temporal muscles was recorded simultaneously with three dimensional incisor point movement of the mandible. Data were sampled and analyzed by an on-line computer system. Patterns of medial pterygoid muscle activity were consistent for ipsilateral chewing and demonstrated activity of the muscle on the chewing side that peaked near the onset of intercuspation. The muscle on the contralateral side was active at the onset of intercuspation for subjects with a chopping stroke and inactive for those with a more lateral stroke guided into intercuspation on cuspal inclines. Activity in the early part of the closing phase was associated with a marked jaw movement toward the chewing side. There was generally less activity in protrusive than intercuspal clenching when occlusion was normal but more activity if marked incisal wear was present or multiple tooth contacts could be attained on protrusion. Intercuspal clenching initiated less activity when force was directed posteriorly and more activity when directed anteriorly than vertical intercuspal clenching.

Adolescent↗
PubMed2001

Aberrant muscle between the temporalis and the lateral pterygoid muscles: M. pterygoideus proprius (Henle).

During examination of the positional relationships between the lateral pterygoid and the temporalis muscles and the innervating nerves, an aberrant muscle was observed in three of 66 head halves. The aberrant muscle originated from the medial surface of the anteromedial muscle bundle of the temporalis (Shimokawa et al. 1998, Surg. Radiol. Anat. 20:329-334) and inserted into the inferolateral surface of the lower head of the lateral pterygoid. Due to its location, origin and insertion this aberrant muscle slip is considered to correspond to the pterygoideus proprius described by Henle (1858, Handbuch der Anatomie des Menschen). Based on the innervation findings, the present aberrant muscle might be considered as a remnant muscle bundle between the anteromedial muscle bundle of the temporalis and the lateral pterygoid during differentiation of the lateral masticatory muscle anlage.

Adult↗