SEARCH · PubMed Health
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.
We report a case of angiofibroma confined to the pterygoid muscle plane without involvement of the sphenopalatine foramen or nasopharynx. The lesion was demonstrated on CT, MR, and angiography with typical findings of a hypervascular mass and was surgically resected after embolization.
The precise function of the inferior head of the human lateral pterygoid muscle (IHLP) is unclear. The aim of this study was to clarify the normal function of the IHLP. The hypothesis was that an important function of the IHLP is the generation and fine control of horizontal (i.e., anteroposterior and mediolateral) jaw movements. The activities of 50 single motor units (SMUs) were recorded from IHLP (14 subjects) during two- or three-step contralateral movement (n = 36) and/or protrusion (n = 33). Most recording sites were identified by computer tomography. There was a statistically significant overall increase in firing rate as the magnitude of jaw displacement increased between the holding phases (range of increments: 0.3-1.6 mm). The firing rates during the dynamic phases for each unit were significantly greater than those during the previous holding phases but less than those during the subsequent holding phases. For the contralateral step task at the intermediate rate, the cross-correlation coefficients between jaw displacement in the mediolateral axis and the mean firing rate of each unit ranged from r = 0.29 to 0.77; mean +/- SD; r = 0.49 +/- 0.13 (protrusive step task: r = 0.12-0.74, r = 0.44 +/- 0.14 for correlation with anterior-posterior axis). The correlation coefficients at the fast rate during the contralateral step task and the protrusive step task were significantly higher than those at the slow rate. The firing rate change of the SMUs per unit displacement between holding phases was significantly greater for the lower-threshold than for the higher-threshold units during contralateral movement and protrusion. After dividing IHLP into four regions, the SMUs recorded in the superior part exhibited significantly greater mean firing rate changes per unit displacement during protrusion than for the SMUs recorded in the inferior part. Significantly fewer units were related to the protrusive task in the superior-medial part. These data support previously proposed notions of functional heterogeneity within IHLP. The present findings provide further evidence for an involvement of the IHLP in the generation and fine control of horizontal jaw movements.
Traumatic myositis ossificans, also known as myositis ossificans circumscripta or fibrodysplasia ossificans circumscripta, is a form of dystrophic calcification leading to heterotopic ossification of intramuscular connective tissue. This is usually due to a single severe injury or repeated minor injuries to muscle, although cases without a history of injury have been reported. Heterotopic ossification is rare in the orofacial region, especially in the medial pterygoid muscles. A case of medial pterygoid myositis ossificans with unique computed tomography findings is described.
An unusual case of myositis ossificans of the medial pterygoid muscle has been discussed. It is important to know the exact cause of the temporomandibular joint ankylosis, for successful treatment. Computed tomographic scan and panoramic radiographs are essential diagnostic aids for evaluating conditions such as myositis ossificans. Myositis ossificans can be one of the causes of extra-articular temporomandibular joint ankylosis.
In man, there are large differences in histochemical fibre-type composition, distribution and size between jaw and trunk muscles, probably related to the special functions of the human stomatognathic system. In the hedgehog, the influence of alkaline and acid pre-incubations on the reaction for myofibrillar ATPase was different from that in man, suggesting a different myosin structure; the fibre composition was different also. The masseter, the superficial portion of the temporal and the lateral pterygoid muscles all showed a homogeneous fibre type profile with almost 100 per cent alkali-stable fibres. In two animals, the deep temporal muscles showed an apparent heterogeneous fibre pattern with 81 per cent alkali-stable fibres, 4 per cent alkali-labile fibres and 15 per cent ATPase-intermediate fibres; in one animal 87 per cent alkali-stable fibres and 13 per cent ATPase-intermediate fibres. There was no difference in cross-sectional area between the three fibre types within each muscle, but the fibres of the lateral pterygoid were smaller than the alkali-stable and the alkali-labile fibres of the masseter and temporal muscles. The limb and trunk muscles showed reactions for myofibrillar ATPase similar to the jaw muscles, but had a heterogeneous fibre-type profile. There was no significant difference in cross-sectional fibre area between the jaw and the limb muscles. Thus the jaw and limb muscles of the hedgehog have similar fibre types and about equal fibre size.
Explore the source record for details and available documents.
The total numbers of fibres in transverse histological sections of the pterygoid muscles of Lister rats of various ages were counted on enlarged photomicrographic prints. The number in the medial pterygoid of the male doubled between birth and six weeks. This was followed by a decrease of rather more than 10 percent in the numbers between six weeks and the adult stage in both males and females. The number of fibres in the lateral pterygoid of the male increased by about 45 percent between birth and the adult stage. There were about 15 percent fewer fibres in the medial pterygoid of the adult female than in the male; no such sex difference occurred in the lateral pterygoid. Early precursors of muscle fibres were seen in histological sections of these muscles in the newborn, confirming new fibre formation after birth. Such precursors gradually disappeared, starting with the most primitive, so that by the age of four weeks the muscles had a mature appearance.
OBJECTIVE: (a) To describe the changes in electromyographic (EMG) activity from selected jaw muscles during a standardized lateral jaw movement with the teeth together, and (b) to investigate the effects on jaw muscle activity of changes in both the rate of lateral jaw movement and the relative magnitude of jaw-closing force. DESIGN: In 16 healthy volunteers, recordings were made using a jaw-tracking system, of mid-incisor point (MIPT) movements, as well as EMG activity from the contralateral inferior head of the lateral pterygoid muscle (IHLP), and bilateral anterior and posterior temporalis, masseter and submandibular muscles, during lateral jaw movement tasks at two speeds and two closing force levels with the teeth together. RESULTS: The IHLP was the only muscle to show a consistent increase in activity in association with the outgoing phase of the task and a decrease during the return phase. Under high closing force at slow speed, the EMG activities of the IHLP and bilateral anterior temporalis and masseter muscles were significantly (p < 0.05) higher than those under a low closing force, while there was no significant change (p > 0.05) in bilateral posterior temporalis and submandibular muscles. The change from slow to fast lateral movement at low force did not significantly (p > 0.05) alter the mean activity except for the IHLP (increase in activity) and the contralateral anterior temporalis (decrease in activity). CONCLUSIONS: The data suggest that the IHLP is one of the principal jaw muscles involved in a lateral jaw movement with the teeth together while the other jaw muscles may play a contributory or facilitatory role.
OBJECTIVE: To find out the relationship between the superior lateral pterygoid muscle (SLP) and the disc of the temporomandibular joint. METHODS: The cadavers consisted of 47 TMJ specimens from old humans, were used for the macroscopic and microscopic study. RESULTS: (1) The SLP may insert to the disc, the capsule, the anterior discal attachment of TMJ and to the condyle; (2) On average, 52% of the SLP fibres insert to the condyle, 10% to the articular disc, 24% to the capsule and 14% to the anterior attachment of the disc; (3) There is no association between displacement of disc and the proportion of the SLP insert to the disc; (4) The SLP fibres are jointed into the disc fibres by node or tendon, or jointed and to end. CONCLUSION: The majority of the SLP inserts to the condyle and the contraction of the little part of the SLP, which insert to the disc, should not result in the anterior displacement of the disc.
A case report of trismus after a dental procedure is evaluated by MR imaging. The medial and lateral pterygoid muscles showed inflammatory changes. Etiologies of trismus are reviewed.
The purpose of this study was to investigate electromyography of the inferior heads of lateral pterygoid muscles in experimental displacement of mandible, and its clinical application for reproduction and diagnosis of mandibular position. In the experiments, the mandibular position was changed in vertical and horizontal directions and muscle activity of the inferior heads was analyzed quantitatively. The results obtained were as follows: 1. Muscle activity of inferior heads was increased with amount of the displacement in anterior direction, and reached to great increase in 1.0 mm and 2.0 mm displacement of mandible. 2. No definite tendency of ipsilateral inferior heads was shown in lateral displacement of mandible. 3. Muscle activity of contralateral inferior heads in lateral displacement was increased with amount of the displacement, and 3 muscles showed great increase in 1.0-2.0 mm displacement of mandible. 4. As vertical increase was less than 2.0 mm, muscle activity of the inferior heads was decreased as to that of intercuspal contact position. 5. Muscle activity of the inferior heads in retruded position showed a little increased, but evidently as to that of intercuspal contact position. 6. Increasing patterns of muscle activities in anterior displacement were different from in contralateral displacement. 7. In anterior mandibular position an ability of presuming a mandible displacement over the limits of 1.0 mm from intercuspal contact position was suggested using muscle activity of inferior head as an index, and in lateral mandibular position that over the limits of 1.5 mm suggested.
The authors have studied the relationship between anatomic and CT sections of the lateral pterygoid muscle in 39 anatomic specimens. Good superimposition of the images was found, which seems important in neoplastic invasion of the infratemporal fossa and which may lead to a pathogenic interpretation of the algo-dysfunctional syndrome of the masticatory apparatus.
On the basis of 15 CT scan and MRI studies of normal volunteers, the authors describe the features the lateral pterygoid muscle. A good correlation appears between CT and MR images which would be useful in the staging of tumors in this space, and in the pathophysiology of internal derangements of the temporomandibular joint (TMJ).
The muscle was exposed in 12 lightly anaesthetized monkeys so that electromyographic recordings could be made from the superior and inferior heads. The separately recorded activity in each head was initially examined in relation to activity recorded simultaneously in other jaw muscles or to jaw movements produced actively by the animals or passively induced by the experimenter. Subsequently, the reflex effects of stimuli applied to various oral-facial sites were examined. In general, the superior head was active in association with jaw-closing muscle activity and related movements produced by the animal whereas the inferior head was mainly active in jaw-opening. Both heads increased their activity with passively-induced jaw-opening movements, especially if the jaw-opening was combined with a horizontal deviation of the mandible. Both heads showed reflexly-induced excitation and silent periods as a result of stimuli applied to oral-facial sites, the most effective sites being palatal, lingual, labial and buccal mucosa and the teeth, stimulation of which, as well as stimuli applied to mandibular joint and cutaneous afferents, could also reflexly induce silent periods in both heads. The various effects may be related to mechanisms for protection and stabilization of the mandibular joint and masticatory muscles.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.