OBJECTIVETo investigate the changes in the afferent discharge activities of the sensory nerve endings in muscle spindles of rats with hindlimb immobilization.

METHODSPlaster cast was used immobilize the hindllimbs of rats. Using air-gap technique, the spontaneous discharge of the muscle spindles and its responses to perfusion with succinylcholine (0.05 mg/ml) and suspension in an extended position were observed in isolated muscle spindles from rats with hindlimb immobilization for 3, 7, and 14 days.

RESULTSThe muscle spindles of rat soleus showed a sharp decrease in spontaneous discharge frequency (P<0.01) and response to succinylcholine perfusion after 3 days of hindlimb immobilization (P<0.05). Significant changes of the firing rate in an extended position was observed in rats after a 14-day immobilization (P<0.01). The duration of individual spikes was significantly prolonged following hindlimb immobilization (P<0.01).

CONCLUSIONMuscle spindle discharges decrease significantly in rats following hindlimb immobilization, which might be related to reduced contractile properties of the muscle spindle.

Animals ; Hindlimb Suspension ; Muscle Spindles ; innervation ; Muscle, Skeletal ; innervation ; Rats

Objective To investigate the clinical value of high-frequency ultrasound in the diagnosis of pronator teres syndrome (PTS). Methods The high-frequency ultrasound was employed to examine and measure the median nerve of the pronator teres muscle in 30 patients with PTS and 30 healthy volunteers (control group).The long-axis diameter (LA),short-axis diameter (SA) and cross-sectional area (CSA) of the median nerve were measured.The receiver operating characteristic curve of the median nerve ultrasonic measurement results was established,and the area under the curve (AUC) was calculated.The diagnostic efficiency of each index for PTS was compared with the surgical results as a reference. Results The PTS group showed larger LA[(5.02±0.50) mm vs.(3.89±0.41) mm;t=4.38,P=0.013],SA[(2.55±0.46) mm vs.(1.70±0.41) mm;t=5.19,P=0.009],and CSA[(11.13±3.72) mm² vs.(6.88±2.68) mm²;t=8.42,P=0.008] of the median nerve than the control group.The AUC of CSA,SA,and LA was 94.3% (95%CI=0.912-0.972,Z=3.586,P=0.001),77.7% (95%CI=0.734-0.815,Z=2.855, P=0.006),and 78.8% (95%CI=0.752-0.821,Z=3.091,P=0.004),respectively.With 8.63 mm² as the cutoff value,the sensitivity and specificity of CSA in diagnosing PTS were 93.3% and 90.0%,respectively. Conclusion High-frequency ultrasound is a practical method for diagnosing PTS,and the CSA of median nerve has a high diagnostic value.
Humans ; Forearm/innervation* ; Muscle, Skeletal/innervation* ; Median Nerve/diagnostic imaging* ; Ultrasonography/methods* ; Sensitivity and Specificity

OBJECTIVEAlthough most of nerve injuries associated with Monteggia fracture-dislocation in children are neurapraxias and will recover spontaneously after conservative treatment, surgical exploration of the involved nerve is always required in the cases with the entrapment of posterior interosseous nerve (PIN). However, the necessity and time frame for surgical intervention for specific patterns of nerve dysfunction remains controversial. The aim of the report is to observe and understand the pathology of PIN injury associated with Monteggia fracture-dislocation in children, and to propose the possible indication for the exploration of nerve.

METHODSEight cases, six boys and two girls, with Monteggia fracture-dislocation complicated by PIN injury, managed operatively at the authors?Hospital from 2007 to 2008 were retrospectively reviewed. All the patients underwent the attempted closed reduction before they received exploration of PIN, with open reduction and internal fixation or successful closed reduction.

RESULTSThe PIN was found to be trapped acutely posterior to the radiocapitellar joint in 4 out of 5 Type III Bado's Monteggia fractures. In the remaining cases, since there were longer time intervals from injury to operation, chronic compressive changes and epineural fibrosis of radial nerve were visualized. After a microsurgical neurolysis performed, the complete recovery in the nerve function was obtained in all the cases during the follow-up.

CONCLUSIONThe findings from this study suggest that every case of type III Monteggia fracture-dislocation with decreased or absent function of muscles innervated by PIN and an irreducible radial head in children should be viewed as an indication for immediate surgical exploration of the involved nerve to exclude a potential PIN entrapment.

Female ; Fingers ; innervation ; Fracture Fixation, Internal ; Humans ; Male ; Monteggia's Fracture ; complications ; Muscle, Skeletal ; innervation ; Nerve Compression Syndromes ; etiology ; surgery ; Recovery of Function ; Retrospective Studies ; Thumb ; innervation ; Wrist ; innervation

The location of the motor point of the gastrocnemius muscle was accurately defined relative to surrounding bony landmarks to facilitate the approach to the nerve of the gastrocnemius muscle during treatment for gastrocnemius muscle spasticity. Anatomic dissection of 40 cadaver knees was undertaken for morphometric measurement. The distances from the epicondyle of the femur to the motor branch, and from the motor branch to the motor point of the nerve to the medial head of the gastrocnemius muscle were 3.68 +/- 11.44 mm, and 37.79 +/- 7.80 mm, respectively; while those of the nerve to lateral head of the gastrocnemius muscle were 4.45 +/- 11.96 mm, and 32.16 +/- 4.64 mm, respectively. The tibial nerve lay 44.57 +/- 5.45% and 56.30 +/- 4.73% from the lateral margins of the epicondyle and the fibular head, respectively. Careful consideration of the morphometry of the motor point of the gastrocnemius muscle may provide accurate anatomical guidance, and hence reduce complications during the chemical blockage of these nerves.
Human ; Muscle Spasticity/*therapy ; Muscle, Skeletal/*innervation ; Tibial Nerve/anatomy & histology

OBJECTIVEReport on the intramuscular innervation and vascular supply of the flexor carpi ulnaris (FCU) and the flexor carpi radialis (FCR), the musculo tendon architecture, i.e., the physiological cross-sectional area and fiber length; and explore the possibility of splitting FCU and FCR into 2 parts with individual independent function.

METHODSAnatomic study, angiogram and Sibler's staining technique were carried on human and monkey cadavers. The electric stimulation study was used to reveal independent contraction of each part on monkey FCU and FCR.

RESULTSIt was found that the innervation and blood supply of FCU and FCR come primarily from the proximal neurovascular pedicles. The primary nerve and vascular branch supplying the muscles were divided into 2 subbranches and inserted the proximal quarter of the muscle belly. Then each of the nerve and blood subbranches mn parallel to the central tendon on each side supplying the radial and ulnar compartments of FCU and FCR toward the distal musculotendinous junction. Independence of function of each compartment was confirmed in electrical stimulation studies in primate FCU and FCR. The results of each compartment of the human FCU and FCR architectures were measured and compared with the extensor pollicis longus and the extensor digitorum communis to the index, middle, ring, and small.

CONCLUSIONSBoth FCU and FCR can be split from the distal to the proximal along its tendon into 2 independently functioning neuromuscular compartments. Both radial compartment and ulnar compartment have its own nerve and adequate blood supply. And the study provides useful information for enabling the local transfer of the two muscles as a whole or two separate compartments, both for resurfacing skin soft-tissue defects and for functional tendon transfer.

Adult ; Animals ; Haplorhini ; anatomy & histology ; Humans ; Muscle Contraction ; Muscle, Skeletal ; blood supply ; innervation ; Radius ; Ulna ; Wrist

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

Forearm ; innervation ; Ganglion Cysts ; surgery ; Humans ; Male ; Middle Aged ; Muscle, Skeletal ; innervation ; surgery ; Tendons ; surgery ; Ulnar Nerve ; surgery

OBJECTIVETo study the distribution of intramuscular nerve and blood vessels in forearm muscles and to discuss the possibility of dividing the forearm muscles into independent functional units.

METHODS(1) The muscles were dissected in 10 forearms from 5 fresh adult human cadavers and stained with the Sihler's nerve staining; (2) The blood vessels were studied in eight forearm muscles from 4 fresh adult human cadavers with irrigation of a mixture of 30% barium sulfate and gelatin from brachial artery and then X-photographed. All pictures were compared to study the intramuscular distribution of nerve and blood vessels.

RESULTSThe intramuscular nerve branches were stained purple-black and visualized clearly. The muscles were classified into three types according to the distribution characters of intramuscular nerve and blood vessels. And the types of muscles could be further subdivided into a and b subtypes.

CONCLUSIONAccording to the neurovascular distribution, the forearm muscles in type II a and type III a can be divided into independent function units for muscle functional transplantation.

Adolescent ; Adult ; Aged ; Female ; Forearm ; blood supply ; innervation ; Humans ; Male ; Middle Aged ; Muscle, Skeletal ; blood supply ; innervation ; Young Adult

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

OBJECTIVETo study the features of electromyographic signals of orbicularis oculi muscle (OOM) of normal rabbits in various movement states, and to clarify relationships between functional actions of OOM and their electromyographic signals, hoping to obtain information concerning the electromyographic signals controlling OOM as reference for restoring the eye-closing function by artificial facial nerve prosthesis in patients with unilateral peripheral facial palsy.

METHODSThe electromyographic signals were extracted from OOM of normal rabbits by implanted microelectrodes through upper and lower eyelids. Then the features of these electromyographic signals were analyzed in the time domain and the frequency domain.

RESULTSThe peak values of the absolute electromyographic amplitude for natural continuous eye-opening event, natural continuous eye-closing state, natural eye-blinking movement and evoked eye-closing state were (28.8 ± 4.8) µV, (36.0 ± 4.7) µV, (398.8 ± 195.7) µV, and (715.4 ± 249.7) µV, respectively. The peak frequency values of the power spectrum density (PSD) of electromyographic signals for the four modes were (98 ± 17) Hz, (142 ± 22) Hz, (203 ± 58) Hz, and (349 ± 81) Hz, respectively. The electrical activities during the natural continuous eye-opening event and the natural continuous eye-closing state were stable and displayed low amplitudes. During the spontaneous blink state and the evoked eye-closing state, the electromyographic amplitudes markedly increased, and the increased level in the latter state was stronger than that in the former state. When rabbits continuously closed eyes or opened eyes, all of the peak values of the absolute voltage amplitudes were less than 50 µV. The absolute amplitude values of the starting site were between 50 µV and 60 µV during the spontaneous blink and the evoked eye-closing movements. The whole frequency band of the energy of PSD about OOM was between 0 Hz and 500 Hz, and the focus frequency range was between 20 Hz and 350 Hz.In the time domain, the difference was not significant for the electromyographic signals of OOM between the continuous eye-opening state and the continuous eye-closing movement (P > 0.05), but there were statistically significant differences in the other states for their pairwise comparisons (P < 0.05). In the frequency domain, there was no statistically significant difference for the peak frequency of PSD about the electromyographic signals when comparing the continuous eye-opening state with the continuous eye-closing event (P > 0.05). When comparing this item in the other movements with each other, however, the differences were statistically significant (P < 0.05).

CONCLUSIONSOOM relaxes when eyelid keeps continuously opening. The action of eyelid-closing is due to contraction of this muscle. Each state has its own features of the electromyographic signals for OOM, these features can be used as criteria for computers to judge and identify various movement states of OOM. However, it is difficult to distinguish the natural continuous eye-opening event from the natural continuous eye-closing state, based on the features of electromyographic signals in the time and frequency domain.

Animals ; Blinking ; Electromyography ; Eye Movements ; Eyelids ; innervation ; Facial Paralysis ; Male ; Muscle, Skeletal ; physiology ; Rabbits