Electromyographic study of the trapezius (pars media) and rhomboideus major muscles in free movements of the head

The authors studied the trapezius (pars media) and rhomboideus major muscles in movements of flexion, extension, inclination and rotation of the head. The electromyographic records demonstrated that referred muscles are inactive in these different movements.

Electromyographic study of the trapezius (pars media) and rhomboideus major muscles in movements of the arm (part 1)

The participation of the trapezius (pars media) and rhomboideus major muscles in free movements of abduction, adduction, flexion, extension and hyperextension of the arm was studied electromyographically. These muscles were active and synergic in all analysed movements, both acting with intensity that ranged from moderate to very marked.

Electromyographic study of the trapezius (pars media) and rhomboideus major muscles in movements of the arm (part 2)

The participation of the trapezius (pars media) and rhomboideus major muscles were studied electromyographically in movements of lateral and medial rotation (free and against resistance) of the arm. In the majority of cases both muscles were inactive during the performance of the analysed movements. Cases in which only one or both muscles acted in free rotation occurred only at the second half or ending of the movement. Records of electrical potentials during against resistance rotation were due to tensional efforts at the shoulder level.

Electromyographic study of the trapezius (pars superior) and levator scapulae muscles in the movements of the head

The electromyographic study of the trapezius (pars superior) and levator scapulae mm. in the head movements was carried out in 30 young, adult male volunteers of both sexes and with no antecedent muscular or articular problems. The analysis was carried out with a two-channel TECA TE4 electromyograph and with single coaxial needle electrodes. Inactivity of the trapezius (pars superior) and levator scapulae mm. was noticed in all cases, in flexion and extension movements, whereas in homolateral and heterolateral rotation movements, these muscles showed to be inactive in most cases.

Electromyographic study of the trapezius muscle in free movements of the shoulder

The objective of this study is to analyze the simultaneity of the actions of the three portions of the trapezius (superior portion = TS; middle portion = TM and inferior portion = TI) in elevation, lowering, retraction and protraction of the shoulders. The electromyographic tests were carried out in 20 volunteers using a 4-channel TECA TE 2-7 electromyograph and surface and single coaxial needle electrodes. The electromyographs, obtained with the two types of electrodes, show that in elevation and lowering of the shoulders, TS and TM present increasing and decreasing activity, respectively, from the beginning until the end of these movements. In retraction of the shoulders, TM and TI present increasing activity from the beginning to the end of the movement. In protraction, TS, TM and TI do not show any activity.

Reconsiderations about the clinical importance of the sympathetic skin response

Over the last few years, neurologists have been showing increasing interest in the study of the sympathetic skin response (SSR). In the present report we describe a simple method that permitted us to determine a wide variation of SSR in response to different stimuli such as respiration, deglutition, blinking, skeletal movements, biting, auditory or light stimuli, vocalization, and sphincter contraction. These results raise doubts about the role of SSR as a complementary diagnostic method.

Electromyographic evaluation of the rectus femoris muscle during exercises performed on the leg press

The rectus femoris was analysed in 10 volunteers during knee flexion and extension with the feet in normal, plantar flexion and dorsal flexion positions. Hewlett-Packard surface electrodes, an electromyographic signal amplifier, a computer equipped with an A/D conversion plaque (Model CAD 10/26), software specially designed to record and analyse the signals, Horizontal Leg Press, and electrogoniometers were used. The rectus femoris muscle showed strong potentials at the beginning of knee extension. In the simultaneous bendings of the knee and hip the activity was strong toward the end of the movement. The rectus femoris showed a similar activity both in the upper and lower platforms. As for foot positions, the rectus femoris showed the smallest potentials with the foot in plantar flexion and the largest ones with the foot in dorsal flexion.

Electromyographic analysis of superior belly of the omohyoid muscle and anterior belly of the digastric muscle in mandibular movements

The superior belly of the omohyoid muscle and the anterior belly of the digastric muscle, were studied electromyographically in 20 young volunteers. For each muscle, 1 pair of monopolar electrodes was employed. One was a surface electrode and the other a needle electrode, which was inserted in the belly of the muscle. The surface electrode was placed 1 cm apart from the needle electrode. The most marked action of both muscles was on the movement of lowering the mandible. They also act in those movements for the performance of which they have associated a component of lowering the jaw, propulsion, laterality to the right and the left and retrusion. They are not active in the resting position and during jaw movements of elevation, extrusion and protrusion. Both muscles are active most of the time, simultaneously, but it is not possible to demonstrate that there is a synchronism between their actions.

Morphology and histochemistry of the hyolingual apparatus in chameleons

We reexamined the morphological and functional properties of the hyoid, the tongue pad, and hyolingual musculature in chameleons. Dissections and histological sections indicated the presence of five distinctly individualized pairs of intrinsic tongue muscles. An analysis of the histochemical properties of the system revealed only two fiber types in the hyolingual muscles: fast glycolytic and fast oxidative glycolytic fibers. In accordance with this observation, motor-endplate staining showed that all endplates are of the en-plaque type. All muscles show relatively short fibers and large numbers of motor endplates, indicating a large potential for fine muscular control. The connective tissue sheet surrounding the entoglossal process contains elastin fibers at its periphery, allowing for elastic recoil of the hyolingual system after prey capture. The connective tissue sheets surrounding the m. accelerator and m. hyoglossus were examined under polarized light. The collagen fibers in the accelerator epimysium are configured in a crossed helical array that will facilitate limited muscle elongation. The microstructure of the tongue pad as revealed by SEM showed decreased adhesive properties, indicating a change in the prey prehension mechanics in chameleons compared to agamid or iguanid lizards. These findings provide the basis for further experimental analysis of the hyolingual system. © 2001 Wiley-Liss, Inc.

Electromyographic validation of the trapezius and serratus anterior muscles in the rowing and frontal-lateral cross, dumbbells exercises

The trapezius and serratus anterior muscles were studied in four modalities of rowing exercises executed with two grips, middle and closed, in comparison with the four different modalities of frontal-lateral cross, dumbbells exercise. It was used 24 male volunteers, 18 to 25 years old using a 2-channel TECA TE 4 electromyograph and Hewlett Packard surface electrodes. The results showed that TS acted in a higher significant way in all the modalities of rowing than in the supine lateral raise, inclined supine lateral raise and reverse supine lateral raise, dumbbells exercises, and demonstrated no standing frontal-lateral cross, dumbbells. The SI acted more significantly difference among all the execution modalities of rowing and the inclined supine lateral raise, dumbbells exercises than in all the rowing exercises; even though the activity levels do not make us suggest them as an excellent group of exercises for the development of this muscle.

Kinesiographic study of complete denture movement related to mucosa displacement in edentulous patients.

The mucosa that covers the residual ridges of edentulous patients may present some distortion or displacement when occlusal loading is applied in complete dentures. This distortion and movement of the denture can result in acceleration of residual ridge resorption and loss of retention and stability. The aim of this study was to analyze the pattern of upper complete denture movement related to underlying mucosa displacement. A sample of 10 complete denture wearers was randomly selected, which had acceptable upper and lower dentures and normal volume and resilience of residual ridges. The kinesiographic instrument K6-I Diagnostic System was used to measure denture movements, according to the method proposed by Maeda et al.7, 1984. Denture movements were measured under the following experimental conditions: (A) 3 maximum voluntary clenching cycles and (B) unilateral chewing for 20 seconds. The results showed that under physiological load, oral mucosa distortion has two distinct phases: a fast initial displacement as load is applied and a slower and incomplete recovery when load is removed. Intermittent loading such as chewing progressively reduces the magnitude of the denture displacement and the recovery of the mucosa is gradually more incomplete.

Electromyographic analysis of the arm muscles in front support exercises

The electromyographic activity of the biceps brachii - BB (long head), triceps brachii - TB (long head) and deltoideus - DA (clavicular portion) muscles, during the going (G) and return (R) phases in front support exercise, as well the efficacy of this exercise for the development of these muscles strength were studied in 10 male volunteers. The values were normalized through maximum voluntary isometric contraction (MVIC = 100%) and statistically analyzed using the Friedman, DMS and Wilcoxon non-parametric test. A value of p≤0.05 indicated significance (Campos, 1983). All the muscles presented higher electromyographic activity in the return phase of the movement. The triceps brachii was the muscle which had higher activity in both phases of the movement. It was concluded that the front support exercise is efficient for strength development mainly in the triceps brachii muscle.