Lateral Pterygoid Muscle Volume And Migraine In Patients With Temporomandibular Disorders.

Lateral pterygoid muscle (LPM) plays an important role in jaw movement and has been implicated in Temporomandibular disorders (TMDs). Migraine has been described as a common symptom in patients with TMDs and may be related to muscle hyperactivity. This study aimed to compare LPM volume in individuals with and without migraine, using segmentation of the LPM in magnetic resonance (MR) imaging of the TMJ. Twenty patients with migraine and 20 volunteers without migraine underwent a clinical examination of the TMJ, according to the Research Diagnostic Criteria for TMDs. MR imaging was performed and the LPM was segmented using the ITK-SNAP 1.4.1 software, which calculates the volume of each segmented structure in voxels per cubic millimeter. The chi-squared test and the Fisher's exact test were used to relate the TMD variables obtained from the MR images and clinical examinations to the presence of migraine. Logistic binary regression was used to determine the importance of each factor for predicting the presence of a migraine headache. Patients with TMDs and migraine tended to have hypertrophy of the LPM (58.7%). In addition, abnormal mandibular movements (61.2%) and disc displacement (70.0%) were found to be the most common signs in patients with TMDs and migraine. In patients with TMDs and simultaneous migraine, the LPM tends to be hypertrophic. LPM segmentation on MR imaging may be an alternative method to study this muscle in such patients because the hypertrophic LPM is not always palpable.

Evaluation of the lateral pterygoid muscle using magnetic resonance imaging

Objectives: The aims of this study were to evaluate the visibility of the lateral pterygoid muscle (LPM) in temporomandibular joint (TMJ) images obtained by MRI, using different projections and to compare image findings with clinical symptoms of patients with and without temporomandibular disorders (TMD). Methods: In this study, LPM images of 50 participants with and without TMDs were investigated by MRI. The images of the LPM in different projections of 100 TMJs from 35 participants (70 TMJs) with and 15 participants (30 TMJs) without clinical signs and symptoms of TMD were visible and analysed. Results: The oblique sagittal and axial images of the TMJ clearly showed the LPM. Hypertrophy (1.45%), atrophy (2.85%) and contracture (2.85%) were the abnormalities found in the LPM. TMD signs, such as hypermobility (11.4%), hypomobility (12.9%) and disc displacement (20.0%), could be seen in TMJ images. Related clinical symptoms, such as pain (71.4%), articular sounds (30.4%), bruxism (25.7%) and headache (22.9%), were observed. Conclusions: Patients with TMD can present with alterations in the LPM thickness. Patients without TMD also showed alterations, such as atrophy and contracture, in TMJ images. Recognition of alterations in the LPM will improve our understanding of clinical symptoms and pathophysiology of TMD, and may lead to a more specific diagnosis of these disorders. Dentomaxillofacial Radiology (2010) 39, 494-500. doi: 10.1259/dmfr/80928433

Influence of the lateral pterygoid muscle on the growth of the mandibular condilar cartilage

At the end of the last century, a model to explain clinical observations related to the mandibular growth was developed. According to it, the lateral pterigoid muscle (LPM) was one of the main modulators of the differentiation of mesenquimal cells inside the condyle to condroblasts or osteoblasts, and therefore of the growth of the mandibular condilar cartilage (CCM). The main components of the model were the humoral and the mechanical. Nowadays, the humoral would include growth factors such as IGF-I, FGF-2 and VEGF, which seem to be involved in mandibular growth. Since skeletal muscle can secrete these growth factors, there is a possibility that LPM modulates the growth of CCM by a paracrine or endocrine mechanism. The mechanical component derived from the observations that both the blood flow inside the temporomandibular joint (ATM) and the action of the retrodiscal pad on the growth of the CCM, depend, in part, on the contractile activity of the LPM. Despite the fact that there are some results suggesting  hat LPM is activated under conditions of mandibular protrusion, there is no full agreement on whether this can stimulate the growth of CCM. In this review, the contributions and limitations of the works related to mandibular growth are discussed and a model which integrates the available information to explain the role of the LPM in the growth of the CCM is proposed.

Lateral pterygoid muscle volume and migraine in patients with temporomandibular disorders

Lateral pterygoid muscle (LPM) plays an important role in jaw movement and has been implicated in Temporomandibular disorders (TMDs). Migraine has been described as a common symptom in patients with TMDs and may be related to muscle hyperactivity. This study aimed to compare LPM volume in individuals with and without migraine, using segmentation of the LPM in magnetic resonance (MR) imaging of the TMJ. Twenty patients with migraine and 20 volunteers without migraine underwent a clinical examination of the TMJ, according to the Research Diagnostic Criteria for TMDs. MR imaging was performed and the LPM was segmented using the ITK-SNAP 1.4.1 software, which calculates the volume of each segmented structure in voxels per cubic millimeter. The chi-squared test and the Fisher's exact test were used to relate the TMD variables obtained from the MR images and clinical examinations to the presence of migraine. Logistic binary regression was used to determine the importance of each factor for predicting the presence of a migraine headache. Patients with TMDs and migraine tended to have hypertrophy of the LPM (58.7%). In addition, abnormal mandibular movements (61.2%) and disc displacement (70.0%) were found to be the most common signs in patients with TMDs and migraine. In patients with TMDs and simultaneous migraine, the LPM tends to be hypertrophic. LPM segmentation on MR imaging may be an alternative method to study this muscle in such patients because the hypertrophic LPM is not always palpable.

Insertion of the superior head of the lateral pterigoid muscle in the human fetuses

The lateral pterygoid muscle, more specifically its superior head, as we know, is closely related to the temporomandibular joint (TMJ). Particularly in children, in contrast with what was observed in adults, these joints have been rarely studied, by the anatomic functional aspect, little knowing about its functions in the embryonic and fetal periods. We used, in this work, 12 fetuses ranging in age from 16 to 39 weeks of intrauterine life, where we observed that the superior head of the lateral pterygoid muscle is inserted in the disc and in the articular capsule, in all age groups studied, and also, that the fibers and the thickness of the articular disc is, as well as the articular capsule suffer modifications in accordance with the period of development. © 2007 Sociedad Chilena de Anatom•br>.

Effects of detachment and repositioning of the medial pterygoid muscle on the growth of the maxilla and mandible of young rats

PURPOSE: To analyze the effects of detachment and repositioning of the medial pterygoid muscle on the growth of the maxilla and mandible of young rats through cephalometry. METHODS: Thirty one-month-old Wistar rats were used, distributed into three groups: experimental, sham-operated and control. In the experimental group, unilateral detachment and repositioning of the medial pterygoid muscle was performed. The sham-operated group only underwent surgical access, and the control group did not undergo any procedure. The animals were sacrificed at the age of three months. Their soft tissues were removed and the mandible was disarticulated. Radiographs of the skull in axial projection and the hemimandibles in lateral projection were obtained, and cephalometry was performed. The values obtained were subjected to statistical analyses among the groups and between the sides in each group. RESULTS: There were significant differences in the length of the mandible relative to the angular process in the experimental group and in the height of the mandibular body in the sham-operated group. CONCLUSION: The experimental detachment and repositioning of the medial pterygoid muscle during the growth period in rats affected the growth of the angle region, resulting in asymmetry of the mandible.

Palpation of the lateral pterygoid area in the myofascial pain diagnosis

Objectives. To evaluate the diagnostic value of intraoral palpation at the lateral pterygoid (LP) area as part of the physical examination to detect myofascial pain, according to modified research diagnostic criteria for temporomandibular disorders. Study design. Fouty-four women composed the myofascial pain group, and 33 symptom-free age-matched were the control group. One examiner calibrated and blinded to group distribution performed 2 intraoral bilateral palpations of the lateral pterygoid. Results. The LP area palpation showed sensitivity and specificity values of 79.55% and 77.27%, respectively, and positive and negative likelihood ratios of 3.50 and 0.26, respectively. Conclusions. Palpation at the LP area did not reach acceptable values of specificity, and care must be taken when judging positive response to this procedure.

Myositis ossificans traumatica of the medial pterygoid muscle: a case report.

In this report, we present a case of myositis ossificans traumatica (MOT) of the medial pterygoid muscle that had developed after mandibular block anesthesia administered for endodontic treatment of the lower right second molar, demonstrating typical features of this condition. MOT should be considered as a differential diagnosis when there is severe limitation of jaw opening and an associated trauma. Panoramic radiographs and axial and coronal computed tomography (CT) scans can effectively delineate the calcified mass. Other imaging studies that may be helpful include magnetic resonance imaging (MRI), bone scans, and ultrasound. As shown in our case, calcified masses were found in the right mandibular angle, which severely limited jaw opening. Some earlier reported cases of MOT were treated by extraoral surgical approaches with complete removal of the evolving muscle. The aim of this case report is to present only the diagnostic imaging aspects of myositis ossificans traumatica.

Neurotized lateral gastrocnemius muscle transfer for persistent traumatic peroneal nerve palsy: Surgical technique

INTRODUCTION Persistent traumatic peroneal nerve palsy, following nerve surgery failure, is usually treated by tendon transfer or more recently by tibial nerve transfer. However, when there is destruction of the tibial anterior muscle, an isolated nerve transfer is not possible. In this article, we present the key steps and surgical tips for the Ninkovic procedure including transposition of the neurotized lateral gastrocnemius muscle with the aim of restoring active voluntary dorsiflexion. SURGICAL TECHNIQUE The transposition of the lateral head of the gastrocnemius muscle to the tendons of the anterior tibial muscle group, with simultaneous transposition of the intact proximal end of the deep peroneal nerve to the tibial nerve of the gastrocnemius muscle by microsurgical neurorrhaphy is performed in one stage. It includes 10 key steps which are described in this article. Since 1994, three clinical series have highlighted the advantages of this technique. Functional and subjective results are discussed. We review the indications and limitations of the technique. CONCLUSION Early clinical results after neurotized lateral gastrocnemius muscle transfer appear excellent; however, they still need to be compared with conventional tendon transfer procedures. Clinical studies are likely to be conducted in this area largely due to the frequency of persistant peroneal nerve palsy and the limitations of functional options in cases of longstanding peripheral nerve palsy, anterior tibial muscle atrophy or destruction.

Study About the Development of the Temporomandibular Joint in the Human Fetuses

The temporomandibular joint (TMJ) is a highly specialized articulation that differs from all the other synovial articulations for many reasons. In children, different from what we observe in adults, these articulations have rarely been studied under the morphofunctional aspect, mainly in the embryonary and fetal stages. In this study 10 fetuses with ages varying from 16 to 39 weeks of intrauterine life were used, and it could be observed that the fibers and thickness of the articular disc, as well as the articular capsule and the condylar process, suffer modifications according to age. It was also observed that the superior head of the lateral pterygoid muscle inserts itself in the articular disc and capsule in all the ages studied. Also, the maturation of the articular tissues, especially of the articular disc, as well as, the associated muscles, suggests that the TMJ was able to carry out mandibular movements since the 24(th) week of intrauterine life.

Disfunção craniomandibular em pacientes desdentados totais com alteração da dimensão vertical. -

Pós-graduação em Reabilitação Oral - FOAR

Estudo clínico de prevalência de sinais e sintomas de disfunções craniomandibulares e contatos oclusais cêntricos em pacientes portadores de lesão labiopalatal

A clinical investigation was undertaken to find out the prevalence of craniomandibular signs and symptoms in a group of 11 patients with labiopalatal lesions. The number and distribution of occlusal contacts was evaluated through questionnaire, clinical examination and analysis of mounted casts in partially adjustable articulators in the position of maximum inter cuspation. The most frequent signs and symptoms were articular sounds and lateral pterygoid muscle tenderness to palpation followed by restriction of mouth opening and sensation of tiredness. The number of occlusal contacts was small, mean of 5 contacts per patient, and the site was considered as atypical, 62% of them were on inclined plane surfaces , suggesting occlusal instability. The frequency of signs and symptoms was low and they were of a mild character. The most prevailing signs of craniomandibular dysfunction - articular sounds, muscular tenderness to palpation and restriction of mouth opening - was noticed in only one of the patients

Computer graphics applied to anatomy: a study of two bio-cad modeling methods on finite element analysis of human edentulous hemi-mandible

Modeling is a step to perform a finite element analysis. Different methods of model construction are reported in literature, as the Bio-CAD modeling. The purpose of this study was to perform a model evaluation and application using two methods of Bio-CAD modeling from human edentulous hemi-mandible on the finite element analysis. From CT scans of dried human skull was reconstructed a stereolithographic model. Two methods of modeling were performed: STL conversion approach (Model 1) associated to STL simplification and reverse engineering approach (Model 2). For finite element analysis was used the action of lateral pterygoid muscle as loading condition to assess total displacement (D), equivalent von-Mises stress (VM) and maximum principal stress (MP). Two models presented differences on the geometry regarding surface number (1834 (model 1); 282 (model 2)). Were observed differences in finite element mesh regarding element number (30428 nodes/16683 elements (model 1); 15801 nodes/8410 elements (model 2). D, VM and MP stress areas presented similar distribution in two models. The values were different regarding maximum and minimum values of D (ranging 0-0.511 mm (model 1) and 0-0.544 mm (model 2), VM stress (6.36E-04-11.4 MPa (model 1) and 2.15E-04-14.7 MPa (model 2) and MP stress (-1.43-9.14 MPa (model 1) and -1.2-11.6 MPa (model 2). From two methods of Bio-CAD modeling, the reverse engineering presented better anatomical representation compared to the STL conversion approach. The models presented differences in the finite element mesh, total displacement and stress distribution.

Time series analysis of jaw muscle contraction and tissue deformation during mastication in miniature pigs

Masticatory muscle contraction causes both jaw movement and tissue deformation during function. Natural chewing data from 25 adult miniature pigs were studied by means of time series analysis. The data set included simultaneous recordings of electromyography (EMG) from bilateral masseter (MA), zygomaticomandibularis (ZM) and lateral pterygoid muscles, bone surface strains from the left squamosal bone (SQ), condylar neck (CD) and mandibular corpus (MD), and linear deformation of the capsule of the jaw joint measured bilaterally using differential variable reluctance transducers. Pairwise comparisons were examined by calculating the cross-correlation functions. Jaw-adductor muscle activity of MA and ZM was found to be highly cross-correlated with CD and SQ strains and weakly with MD strain. No muscle’s activity was strongly linked to capsular deformation of the jaw joint, nor were bone strains and capsular deformation tightly linked. Homologous muscle pairs showed the greatest synchronization of signals, but the signals themselves were not significantly more correlated than those of non-homologous muscle pairs. These results suggested that bone strains and capsular deformation are driven by different mechanical regimes. Muscle contraction and ensuing reaction forces are probably responsible for bone strains, whereas capsular deformation is more likely a product of movement.