OBJECTIVE: To study the objectivity and reliability of needle electromyography and nerve conduction for detection of musculus extensor digitorum brevis strength, which may provide a basis for establishing a quantitative detection of muscle strength in forensic clinical study. METHODS: Forty-four healthy people were enrolled as the subjects, and during toe dorsiflexion, the following items including needle electromyography indexes, motor unit potential (MUP) amplitude, MUP count, recruitment reaction type, and nerve conduction detection indexes, compound muscle action potential (CMAP) amplitude, CMAP latent period and motor nerve conduction velocity (MNCV), were simultaneously detected under the cooperation and disguise condition. RESULTS: Under the cooperation condition, regardless of the same operator or different operators, there were good test-retest reliabilities in MUP amplitude, CMAP amplitude, CMAP latent period and MNCV, while there were normal test-retest reliabilities in MUP count and recruitment reaction type and the repeatability of the same operator was slightly better than the repeatability between different operators. Under the disguise condition, test-retest reliabilities of MUP amplitude, CMAP amplitude, CMAP latent period and MNCV were relatively high, while test-retest reliabilities of MUP count and recruitment reaction type were relatively low. CONCLUSION There are good test-retest reliabilities in MUP amplitude, CMAP amplitude, CMAP latent period and MNCV, which can be conducive to comparison between different operators and results at various times; MUP count and recruitment reaction type, which can be easily affected by subjectivity of operators and examinees, can be used to differentiate whether an examinee disguises or not. The indexes used to objectively judge muscle strength remain to be further investigated.
Electrodes, Implanted ; Electromyography ; Humans ; Muscle Strength/physiology* ; Muscle, Skeletal/innervation* ; Neural Conduction/physiology* ; Reproducibility of Results ; Toes

OBJECTIVETo study the degeneration and regeneration of skeletal muscle after denervation.

METHODSDenervation was carried out in gastrocnemius muscles in 30 adult BALB/C mice by cutting the sciatic nerve. The gastrocnemius muscles were removed at 1, 2, 4, 8, 12, 16 weeks after denervation, respectively. Specimens were processed for histological study and immunohistochemical technique.

RESULTSMuscle fiber atrophy followed by degerneration and regeneration was observed in the early period of denervation. Fusion of the regenerated muscle cells with each other followed by degeneration of the cells and growth of fibro-connective tissue were observed in the later stage. The expression of myoglobin and actin decreased in 1-4 weeks after denervation. The postive expression of the proteins was observed in some 8 weeks' cells and in many degenerated 12-14 weeks' muscle cells.

CONCLUSIONDegeneration and regeneration may coexisted in the denervated muscles. The regenerated muscle cells can't fully develop due to the deficit of nerve regulation and degenerate again. The regenerated muscle cells will melt each other and can't develop to mature muscle fiber in the later stage.

Animals ; Female ; Mice ; Mice, Inbred BALB C ; Muscle Denervation ; Muscle Fibers, Skeletal ; pathology ; Muscle, Skeletal ; innervation ; physiology ; Muscular Atrophy ; physiopathology ; Nerve Regeneration ; physiology ; Sciatic Nerve ; physiology ; surgery

OBJECTIVETo study the changes of the muscle strength after the selective tibial neurotomy and the relationship between the changes and the quantities of neurotomy, and to discuss the clinical significances.

METHODSTwenty-four normal SD rats were divided into 4 groups with 6 in each. In group A, the left tibia nerve were cut off by 80%. 60% in group B, 40% in group C, 20% in group D, with the right as the control side. After 6 weeks measure the strength of the crural triceps and the weight of them.

RESULTSIn all the groups muscle weight and muscle strength decreased. 88.2% strength decreased on the average in group A, 54.2% in group B, 19.5% in group C, 4.7% in group D.

CONCLUSIONIt will not damage strength of the crural triceps to cut off below 40% tibial nerve in SD rats.

Animals ; Female ; Male ; Muscle Contraction ; physiology ; Muscle Denervation ; Muscle, Skeletal ; innervation ; physiopathology ; Rats ; Rats, Sprague-Dawley ; Tibial Nerve ; surgery

A method of motor unit action potentials (MUAP) detection and classification was introduced to explore the firing information of recruited motor units in the neural muscular system. Based on the continuous wavelet transform, the first order Hermite-Rodriguez (HR) function was used as the mother wavelet, and the binary hypothesis testing algorithm was combined to detect and localize the MUAP waveforms in the surface electromyography (sEMG) signal. Then, the fuzzy k-means clustering and minimum distance classifying algorithms were applied to the primary clustering of the detected MUAPs. Finally, the template matching method was used to solve the problem of the unclassified waveforms. The experimental results showed that the kinds of MUAP information from the recorded sEMG signal could be acquired by waveform detection and pattern recognition. The proposed method does not require multi-channel sEMG signals; it just utilizes the single channel signal to analyze the MUAPs, and it can improve the decomposition efficiency.
Action Potentials ; physiology ; Algorithms ; Electromyography ; methods ; Humans ; Motor Neurons ; physiology ; Muscle, Skeletal ; innervation ; physiology ; Signal Processing, Computer-Assisted ; Wavelet Analysis

OBJECTIVEThe aim of this study was to examine the effects of deep branches of cervical plexus on trapezius muscle.

METHODSThe evoked electromyography of 32 trapezius of 16 SD rats was examined in different time and results obtained were processed by statistical methods.

RESULTSAfter cutting the accessory nerves, stimulating the deep branches of cervical plexus evoked the myoelectricity, the myoelectricity results varied according to different time.

CONCLUSIONThe deep branches of cervical plexus are another important motorial supply to trapezius muscles. After cutting the accessory nerves, if the branches were undamaged, the shoulder's function would be greatly preserved.

Accessory Nerve ; physiology ; Animals ; Cervical Plexus ; physiology ; Electromyography ; Male ; Muscle, Skeletal ; anatomy & histology ; innervation ; physiology ; Neck Dissection ; adverse effects ; Neck Muscles ; anatomy & histology ; injuries ; physiology ; Rats ; Rats, Sprague-Dawley ; Shoulder ; innervation

OBJECTIVETo determine the effect of tension relaxation by small needle knife on the muscle tension and morphology changes of nerve terminals when sustained pressure was applied to muscular tissue.

METHODSRat gracilis muscles were exposed to pressure in vivo at 70 kPa for 2 hours. Sixty rats were divided into three groups: normal, control and experiment group respectively. In all rats except the six normal ones, the lower legs were considered as the control group, and the right left as experiment group. At day 1, 2 and 3, 9 rats from the two groups were randomly selected and sacrificed in order to determine the muscle tension change. At the same time, muscle histology and morphology changes of nerve terminals were observed.

RESULTSAbnormal tension increased in muscles under compression of 70 kPa. At the 1st and 2nd days, there were no significant differences between the two groups. Compared with control group, the tension was lower in experiment group, and there was statistically significant difference (P < 0.01) between the two groups. Exposure of striated muscle tissue to intensive and prolonged compression may pathologically alter its microstructure. Histological evaluation showed that this stiffening accompanied extensive necrotic damage. The changes could not be found in the nerve terminals.

CONCLUSIONDeep muscle tissue that undergoes prolonged compression may significantly increase its stiffness during acute injury. Tension relaxation applied by small needle knife can effectively reduce the mechanical load which is harmful to the whole tissue.

Animals ; Biomechanical Phenomena ; Female ; Male ; Medicine, Chinese Traditional ; Muscle Tonus ; Muscle, Skeletal ; innervation ; pathology ; physiology ; Nerve Endings ; pathology ; Pain Management ; Rats ; Rats, Sprague-Dawley

In the present study we made out an animal model on rabbit whose trigeminus and facialis nerves were simultaneously or only the latter one was severed. The pathological changes in facial muscle atrophy under different nerve injuries were investigated. The degeneration of contractile proteins of upper lip muscle -- myosin and actin was observed. In addition, we also examined the ultrastructural changes in the muscle atrophy in the two above-mentioned nerve injury cases. We observed that the intact trigeminus nerve could delay and lighten the atrophy of facialis-denervated facial muscle and attenuate the degeneration of myosin and actin, as well as decrease the increment of collagen and maintain the ultrastructure of the thick and thin muscle filaments. These results may provide the possibility of improvement of clinical treatment for facial muscle palsy.
Animals ; Denervation ; Facial Muscles ; innervation ; pathology ; Facial Nerve ; physiology ; surgery ; Female ; Muscle Fibers, Skeletal ; diagnostic imaging ; Muscular Atrophy ; pathology ; Rabbits ; Trigeminal Nerve ; physiology ; surgery ; Ultrasonography

The two main factors to affect the style of the recruitment are temporal recruitment and spatial recruitment. This study sought a new way to analyze the recruitment with the modern spectrum method. The abnormal spatial recruitment and temporal recruitment of varied injury degrees of intramuscular neuron were compared through the AR model. At last, AR coefficients were extracted and passed through BP artificial neuron network to classify different NEMG signals and good result was gained.
Action Potentials ; physiology ; Electromyography ; instrumentation ; methods ; Electrophysiology ; Humans ; Models, Neurological ; Models, Theoretical ; Muscle Contraction ; physiology ; Muscle, Skeletal ; innervation ; physiology ; Needles ; Neural Networks (Computer) ; Pattern Recognition, Automated ; Peripheral Nerve Injuries ; Signal Processing, Computer-Assisted ; instrumentation

This study was designed to investigate the incidence of lateral root of the ulnar nerve through cadaveric dissection and to analyze its impact on myotomes corresponding to the flexor carpi ulnaris (FCU) assessed by electrodiagnostic study. Dissection of the brachial plexus (BP) was performed in 38 arms from 19 cadavers, and the connecting branches between the lateral cord and medial cord (or between lateral cord and ulnar nerve) were investigated. We also reviewed electrodiagnostic reports from January 2006 to May 2008 and selected 106 cases of single-level radiculopathy at C6, C7, and C8. The proportion of abnormal needle electromyographic findings in the FCU was analyzed in these patients. In the cadaver study, branches from the lateral cord to the ulnar nerve or to the medial cord were observed in 5 (13.1%) of 38 arms. The incidences of abnormal electromyographic findings in the FCU were 46.2% (36/78) in C7 radiculopathy, 76.5% (13/17) in C8 radiculopathy and 0% (0/11) in C6 radiculopathy. In conclusion, the lateral root of the ulnar nerve is not an uncommon anatomical variation of the BP and the FCU commonly has the C7 myotome. Needle EMG of the FCU may provide more information for the electrodiagnosis of cervical radiculopathy and brachial plexopathy.
Brachial Plexus/anatomy & histology/physiology ; Brachial Plexus Neuropathies/diagnosis ; Cadaver ; Electrodiagnosis/methods ; Electrophysiology/*methods ; Female ; Forearm/*anatomy & histology ; Humans ; Male ; Muscle, Skeletal/*innervation/physiology ; Radiculopathy/diagnosis ; Ulnar Nerve/*anatomy & histology/physiology