Distribución nerviosa interna del músculo temporal humano: consideraciones anatómicas y quirúrgicas / Internal nervous distribution of the human temporal muscle: anatomical and surgical considerations

Resumen Introducción: Conocer en detalle la inervación interna del músculo temporal humano permite realizar múltiples técnicas quirúrgicas y tratamientos de patologías que involucran al territorio craneofacial. Si bien en la literatura se ha descrito la inervación interna del músculo temporal humano basado en micro-disección directa, la técnica de tinción de Sihler es una herramienta ventajosa para el estudio anatómico ya que permite observar ramos nerviosos pequeños sin perder su relación tridimensional con las fibras musculares. Objetivo: Describir la distribución nerviosa al interior del músculo temporal humano en cadáveres al aplicar el método de Sihler y analizar su asociación anátomo quirúrgica. Materiales y Método: Ocho músculos temporales humanos previamente disecados fueron sometidos al método de tinción de Sihler. Cada una de las muestras se observó bajo lupa estereoscópica y transiluminación; finalmente para su descripción se dividió al músculo en tres regiones. Resultados: Se determinó la presencia de tres troncos nerviosos principales: el temporal profundo anterior, el temporal profundo medio y temporal profundo posterior, los que discurren de profundo a superficial. Además, se observaron ramos colaterales de menor calibre del nervio temporal profundo posterior que en forma de arco comunican las tres regiones del músculo. Conclusión: Se describió una distribución nerviosa interna común para los músculos estudiados en las tres dimensiones del espacio, conocimiento útil para innovar en terapias clínico-quirúrgicas del territorio craneofacial.

Introduction: Knowing in detail the inner innervation of the human temporal muscle allows to perform multiple surgical techniques and treatments of pathologies that involve the craniofacial territory. Although the internal innervation of the human temporal muscle based on direct microdissection has been described in the literature, the Sihler staining technique is an advantageous tool for anatomical study since it allows observing small nerve branches without losing its three-dimensional relationship with muscle fibers. Aim: To describe the nervous distribution within the human temporal muscle in cadavers by applying the Sihler method and analyzing its surgical anatomical association. Materials and Method: Eight previously dissected human temporal muscles were subjected to the Sihler staining method. Each one of the samples was observed under stereoscopic magnification and transillumination, finally for its description the muscle was divided into three regions. Results: The presence of three main nervous trunks was determined: the anterior deep temporal, the deep medium temporal and the posterior deep temporal, those that run from deep to superficial. In addition, collateral branches of lesser caliber of the posterior deep temporal nerve that in the form of an arc communicate the three regions of the muscle were observed. Conclusion: A common internal nervous distribution was described for the muscles studied in the three dimensions of space, useful knowledge to innovate in clinical-surgical therapies of the craniofacial territory.

Alterations in the stomatognathic system due to amyotrophic lateral sclerosis

Abstract Objectives: To compare the molar bite force, electromyographic activity, chewing efficiency and thickness of the masseter and temporalis muscles in individuals with amyotrophic lateral sclerosis (ALS) and healthy individuals. Material and Methods: Thirty individuals enrolled in the study were divided into the study group (with ALS, n=15) and control group (healthy individuals, n=15). Data regarding molar bite force (right and left), electromyographic activity (mandibular rest, right and left laterality, protrusion, and maximum voluntary contraction), chewing efficiency (habitual and non-habitual), and masticatory muscle thickness (rest and maximum voluntary contraction) were tabulated and subjected to statistical analysis (Student's t-test, p≤0.05). Results: Comparisons between the groups demonstrated a statistically significant increase in the electromyographic activity of the right masseter (p=0.03) and left masseter (p=0.03) muscles during mandibular rest; left masseter (p=0.00), right temporalis (p=0.00), and left temporalis (p=0.03) muscles during protrusion; and right masseter (p=0.00), left masseter (p=0.00), and left temporalis (p=0.00) muscles during left laterality, in individuals with ALS as compared with healthy individuals. A statistically significant decrease was observed in the habitual chewing efficiency of the right masseter (p=0.00) and right temporalis (p=0.04) muscles in individuals with ALS. No statistically significant difference between the groups was found the masticatory muscle thickness and maximal molar bite force. Conclusions: ALS may lead to modifications in the activities of the stomatognathic system, including muscular hyperactivity and reduction in chewing efficiency; however, no change has been observed in the masticatory muscle thickness and molar bite force.

Mejoramiento electromiográfico de los maseteros y temporales, en pacientes con Clase III tratados neuromuscularmente con TENS / Electromyographic improvement of masseters and temporal, in patients with Class III treated neuromuscularly with TENS

Las Clases III están caracterizadas por una pérdida de dimensión vertical, asociada a un acortamiento de las inserciones y desbalance musculares. Este estudio fue diseñado para determinar los cambios en la amplitud de la electromiografía (EMG) de la actividad muscular de los maseteros (M) y temporales (T) en reposo y en apretamiento en pacientes con Clase III, tratados neurofisiológicamente con electroestimulación nerviosa transcutánea (Transcutaneous Electrical Nerve Stimulation - TENS), utilizando un dispositivo intraoral (DIO) las 24 horas durante 30 días. Doce pacientes con Clase III molar (edad promedio: 27,7+-1,2 años) formaron parte del grupo tratado con TENS y DIO, y 10 pacientes con edades similares de Clase III, sin tratamiento, conformaron el grupo control. La EMG muscular de M y T fue estudiada antes y después del tratamiento. Los datos fueron analizados utilizando la prueba "t" de Student; adicionalmente, se calculó la media y el desvío estándar de la actividad de cada músculo. Los pacientes tratados con TENS y DIO presentaron una disminución marcada de la hiperactividad en reposo de los M y T (p=0,0001 - asociación altamente significativa - A/S) y un aumento de la misma en apretamiento (p=0,0001 A/S). El grupo control mantuvo similar actividad en reposo y en la EMG en apretamiento, mostrando asociaciones no significativas. Estos resultados confirman que utilizar el TENS y el DIO en pacientes mejora la actividad de los músculos M y T , disminuyendo la hiperactividad en reposo y mejorando la misma en apretamiento. De este modo cambiaría sustancialmente la posición inicial de la oclusión para tratar las maloclusiones de Clase III, lo cual facilita el diagnóstico, pronóstico y plan de tratamiento.

Classes III are characterized by a loss of vertical dimension associated with a shortening of the muscle attachments and imbalance. This study was designed to stablish the changes in the amplitude of the electromyogram (EMG) of temporal (T) and masseter (M) muscle activity at rest and during clenching in patients with Class III, neurophysiologically treated with Transcutaneous Electrical Nerve Stimulation (TENS), using an intraoral device (DIO) 24 hours for 30 days. Twelve patients with Class molar relation (mean age, 27.7+-1.2 years) were part of the group treated with TENS and DIO and 10 untreated patients with similar ages and Class III, formed the control group. The muscle EMG of M and T was studied before and after treatment. Data were analyzed using the Student´s test, additionally, mean and standard deviation of the activity of each muscle was calculated. Patients treated with TENS and DIO showed a marked decrease in hyperactivity of M and T at rest (p=0.0001 A/S) and an increase of it during clenching (p=0.0001 A/S). The control group kept similar activity at rest and in the EMG during clenching, showing no significant associations. These results confirm that using TENS and DIO in patients improves muscle activity of T and M as decreasing hyperactivity at rest and improving it during clenching. Thus, the initial position of the occlusion to treat Class III malocclusions should substantially change, thereby providing diagnosis, prognosis and treatment plan.

Ultrasonographic evaluation of inflammatory swellings of buccal space.

Objectives : The main objective of the study was a) to differentiate cellulitis and abscess in buccal space region, b) to study the ultrasonographic anatomy of cheek region and c) to investigate the use of ultrasound in the diagnosis of inflammatory swellings of cheek region. Patients and Methods : The study consisted of 25 patients with unilateral buccal space inflammatory swellings of odontogenic origin. The contra lateral side was used as control. Toshiba ultrasonographic device with a linear array transducer (5-8 MHz) was used. The areas of interest were scanned under both transverse and longitudinal sections and were interpreted by a single observer. The clinical diagnosis of cellulitis or abscess was confirmed by the absence or presence of pus respectively both sonographically and by aspiration. Also various anatomical structures present in buccal space were studied. Results : Clinically 23(92%) were diagnosed as buccal space abscess and 2 (8%) were cellulitis. Ultrasonographically and therapeutically 24 (96%) were buccal space abscess and 1 (4%) was cellulits. The sensitivity of clinical criteria over ultrasonographic diagnosis was 96% with a specificity of 100%. Also the cheek thickness in males and females varied from 8.2 to 17.1mm with a mean of 11.6mm±2.1 (SD) and 8.2 mm to 14.2 mm with a mean of 11±1.8 (SD). The subcutaneous tissue appeared moderately echogenic, buccinator - highly echogenic, deep adipose tissue - less echogenic and parotid duct was appreciated as a thin hyperechogenic band crossing the buccinator muscle. Buccal space, masticator space and parotid space were appreciated. Conclusion : This study supports the ultrasonographic method of imaging of orofacial inflammatory swellings with high sensitivity and specificity. This imaging modality can also help in aspiration of pus in different spaces. We have described the ultrasonographic anatomy of the above mentioned spaces which can help a beginner in this field.