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Insertion of the upper head of the lateral pterygoid (UHLP) in the temporomandibular joint disc (TMJ) has been linked to anterior displacement of the disc and temporomandibular disfunction. The aim of this study was to determine in human adults, the percentage of muscle fiber in the upper head of the lateral pterygoid muscle inserted in the articular disc. A systematic review of the literature was designed beginning with articles published in Medline, Lilacs and Scielo data bases between the years 1990 and 2010. Key words "Lateral Pterygoid Muscle" and Pterygoid Lateral Muscle" were used, and the term MeSH "Pterygoid Muscle" with Boolean OR "Lateral Ptrerygoid Muscle" AND "Insertion" and the free terms "Pterygoid Lateral Muscle Disc Articular" and "Pterygoid lateral Muscle Meniscus". Of the 156 articles obtained and analyzed, 18 articles meeting eligibility criteria were selected. Based on those articles the percentage of insertion of the CSPL in the TMJ disc was evaluated, each one was subsequently assigned a level of evidence according to OCEBM Oxford Centre Evidence Based Medicine. Only four articles answered the research inquiry, three studies were histological and one used imaging techniques with cross section slices with an adequate evidence level (1B). However, results differed with insertion percentages from 2 percent to 69.8 percent being reported in the superior head of the lateral pterygoid muscle in the articular disc.

La actividad de la inserción de la cabeza superior del pterigoideo lateral (CSPL) en el disco de la articulación temporomandibular (ATM) ha sido vinculada al desplazamiento anterior del disco y disfunción temporomandibular. El propósito de este estudio fue determinar el porcentaje de fibras musculares de la cabeza superior del músculo pterigoideo lateral que se insertan en el disco articular, en humanos adultos. Se diseñó una revisión sistemática de la literatura a partir de artículos primarios publicados en las bases de datos Medline, Lilacs y Scielo entre los años 1990 y 2010. Se utilizaron las palabras clave "Músculo Pterigoideo Lateral" y "Pterygoid Lateral Muscle", el Término MeSH: "Pterygoid Muscle" con los boleanos OR "Lateral Pterygoid Muscle" AND "Insertion" y los Términos Libres: "Pterygoid Lateral Muscle Disc Articular" y "Pterygoid lateral Muscle Meniscus". Se obtuvieron 156 artículos, los cuales fueron analizados y se seleccionaron 18 que cumplieron con los criterios de elegibilidad. En base a estos artículos se evaluó el porcentaje de inserción de la CSPL en el disco de la ATM, posteriormente a cada uno se les otorgó un nivel de evidencia de acuerdo a la clasificación de Oxford Centre Evidence Based Medicine (OCEBM). Solo 4 artículos respondieron a la pregunta de investigación, 3 estudios fueron histológicos y 1 imagenológico, todos con diseños de cortes transversales con buen nivel de evidencia (1b). Sin embargo los resultados fueron disímiles, reportándose porcentajes de inserción del 2 al 69,8 por ciento de la cabeza superior del pterigoideo lateral en el disco articular.

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INTRODUCTION: Otomandibular dysplasia is a syndrome of deformities that can affect all latero-facial structures, although the main clinical manifestations include maxillary and mandibular hypoplasia and possibly the absence of the temporo-mandibular joint. OBSERVATION: A 18-year-old man with otomandibular dysplasia was treated by grafting in a homologous joint and bone branch. DISCUSSION: There is no consensus on the best age to treat the syndrome and on treatment for mandibular hypoplasia and to reconstruct the temporo-mandibular joint. An alternative to the suggested treatments consists in reconstructing the joint and the branch affected by hypoplasia by grafting in a homologous joint and bone branch.

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El desplazamiento discal en la articulación temporomandibular es una afección habitual. En algunos casos, el disco desplazado sin reducción, puede producir, si la manifestación ocurre durante el período de crecimiento, alteraciones de desarrollo cóndilo mandibular, tales como asimetrías y disminución del tamaño de esas estructuras a partir de procesos degenerativos a nivel condilar. Estos hechos han sido observados en otros estudios de los que se hace una breve reseña. A continuación se presentan dos casos clínicos en pacientes con DDsR, proceso degenerativo condilar, alteración de crecimiento y asimetría.

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Direct measurement of temporomandibular joint (TMJ) tissue deformation requires animal experimentation. Most of the available data pertain to the mechanical strain on the bone surfaces around the joint. However, bone is rarely the first joint tissue to show injury, being affected after damage to collagenous tissues such as the disc or capsule. Capsular ligaments guide or limit movement, while the intra-articular disc may also distribute joint loads. However, these tissues are difficult to visualize dynamically and not suitable for strain gage attachment, so in vivo deformations are poorly understood. Using pigs as the best nonprimate model for human TMJ function, we implanted differential variable reluctance transducers to measure antero-posterior strain in the lateral aspect of the intra-articular disc. The results were compared to previously published data on the TMJ capsule. Passive manipulation in anesthetized animals indicated that opening, protrusion, and contralateral movements caused the disc to elongate. On the contrary, closing, retrusion and ipsilateral movements caused disc shortening. These strains are opposite to those observed in the capsule and are expected on anatomical grounds. Surprisingly, disc strain during mastication differed from that during manipulation. The disc elongated during jaw closure, more on the retruding balancing side (16% +/- 1) than on the working side (8% +/- 2). This anomalous behavior may reflect compressive loading, such that the disc elongates as a result of the Poisson effect rather than condylar movement. Because the capsule also elongates during the power stroke, especially on the balancing side, both disc and capsule are maximally loaded on the same side at the same moment.

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Se realizó un estudió de tipo ensayo clínico experimental en el cual de forma aleatoria se obtuvo una muestra de 15 pacientes, todos con diagnóstico de Disfunción Temporomandibular. A todos se les había tratado previamente con tratamiento conservador sin obtener resultados favorables en relación a sintomatología.Se les reatizó radiografías diagnósticas y modelos en yeso de las arcadas dentales, luego se montaron en un articulador semiajustable (Panadent), midiéndose en este paso el indicador de posición condilar (CPI), todos los pacientes fueron examinados clínicamente y se les lleno una historia clínica detallando signos y síntomas relacionados con la disfunción temporomandibular.Se les colocó un plano de miorrelajación (splint), que fue utilizado durante tres meses, obteniendo así un nuevo indicador de posición condilar, en esta etapa los pacientes fueron nuevamente examinados y entrevistados para observar la relación entre la nueva posición condilea y los sígnos y síntomas de la disfunción temporomandibular. Se observó que hubo una mejoría notable al modificar la posición del cóndilo mandibular, con un CPI inicial promedio de 3.l6mm en el sexo femenino y 3.5mm en el masculino, al final del tratamiento se obtuvo 1.8 mm (masculino)y 1.llmm (femenino).Los ruidos articulares desaparecieron en un 80 porciento, desapareció la traba mandibular en un 100 porciento, el dolor de tipo muscular mejoró en un 60 porciento, la causa mas frecuente fue la ausencia de piezas dentales(53 porciento), seguido de contacto oclusal prematuro (46.6 porciento)...

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Background: The temporomandibular joint is an oval fibrous plate that completely divides the joint and accommodates irregularities existent in the bone articular surfaces. Aim: To study the frequency of temporomandibular joint disk abnormalities among Colombian subjects. Material and methods: We studied 120 temporomandibular joint disks obtained from fresh cadavers arrived in the Instituto de Medicina Legal, in Cali Colombia. These were analyzed according to subjectÕs dental status and age. Results: Nineteen percent of disks had small erosions. In 7,5 percent of disks there were wider erosions or perforations. Twenty six percent of discs were very thin and this alteration was seen mostly in people aged 50 years or older. Conclusions: These results are intermediate between those who claim that disk perforations are rare and those who had shown tile opposite. The loss of dental pieces seems to be a risk factor leading to such disk perforation

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Alguns pacientes apresentam limitação de abertura bucal (hipomobilidade) devido a contínuo bloqueio mandibular resultante da restrição dos movimentos do disco articular ocasionado por sua aderência à fossa, por um efeito de vácuo entre o disco e a fossa no compartimento superior da ATM ou por alteração na consistência do fluido sinovial. Um dos tratamentos do bloqueio mandibular é a artrocentese que consiste na lavagem da ATM via dupla agulha com concomitante manipulação manual da articulação. É indicada quando há hipomobilidade da ATM que não melhora com a manipulação manual mandibular isoladamente e/ou tratamento sintomático inicial (medicação antiinflamatória, fisioterapia e placa de mordida). A eficácia da artrocentese pôde ser comprovada neste trabalho, durante o tratamento do paciente L.J., 49 anos de idade, sexo masculino, branco com queixa principal de severa limitação de abertura bucal, episódios intermitentes de bloqueio mandibular, estalos e dor moderada na ATM direita, com duração de dois meses. No pós-operatório imediato, pôde-se constatar a normalização da abertura bucal máxima, ausência da dor da ATM comprometida e amplitude normal dos movimentos mandibulares de lateralidade e protrusão. Após acompanhamento de 110 dias o paciente apresentou-se sem dor na ATM e com abertura bucal e movimentos mandibulares horizontais normais. Conclui-se que a artrocentese é terapia pouco invasiva e eficaz na resolução do bloqueio mandibular persistente. É método realizável a nível ambulatorial, simples, de fácil execução, bem aceito pelo paciente e de baixo custo, devendo ser tentada antes da cirurgia aberta da ATM

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