Correlation between Elbow Flexor Muscle Strength and Needle Electromyography Parameters after Musculocutaneous Nerve Injury / 法医学杂志

OBJECTIVES@#To explore the changes of elbow flexor muscle strength after musculocutaneous nerve injury and its correlation with needle electromyography (nEMG) parameters.@*METHODS@#Thirty cases of elbow flexor weakness caused by unilateral brachial plexus injury (involving musculocutaneous nerve) were collected. The elbow flexor muscle strength was evaluated by manual muscle test (MMT) based on Lovett Scale. All subjects were divided into Group A (grade 1 and grade 2, 16 cases) and Group B (grade 3 and grade 4, 14 cases) according to their elbow flexor muscle strength of injured side. The biceps brachii of the injured side and the healthy side were examined by nEMG. The latency and amplitude of the compound muscle action potential (CMAP) were recorded. The type of recruitment response, the mean number of turns and the mean amplitude of recruitment potential were recorded when the subjects performed maximal voluntary contraction. The quantitative elbow flexor muscle strength was measured by portable microFET 2 Manual Muscle Tester. The percentage of residual elbow flexor muscle strength (the ratio of quantitative muscle strength of the injured side to the healthy side) was calculated. The differences of nEMG parameters, quantitative muscle strength and residual elbow flexor muscle strength between the two groups and between the injured side and the healthy side were compared. The correlation between elbow flexor manual muscle strength classification, quantitative muscle strength and nEMG parameters was analyzed.@*RESULTS@#After musculocutaneous nerve injury, the percentage of residual elbow flexor muscle strength in Group B was 23.43% and that in Group A was 4.13%. Elbow flexor manual muscle strength classification was significantly correlated with the type of recruitment response, and the correlation coefficient was 0.886 (P<0.05). The quantitative elbow flexor muscle strength was correlated with the latency and amplitude of CMAP, the mean number of turns and the mean amplitude of recruitment potential, and the correlation coefficients were -0.528, 0.588, 0.465 and 0.426 (P<0.05), respectively.@*CONCLUSIONS@#The percentage of residual elbow flexor muscle strength can be used as the basis of muscle strength classification, and the comprehensive application of nEMG parameters can be used to infer quantitative elbow flexor muscle strength.

Progress on the Muscle Function Evaluation and Its Forensic Application / 法医学杂志

Accurate evaluation of muscle function helps to understand the recovery of muscle, bone, nervous system diseases or injuries, especially for muscle dysfunction caused by peripheral nerve injury.Therefore, the methods of muscle function evaluation have been the focus of researchers, with new methods having been constantly proposed.Muscle strength testing is an important part of muscle function evaluation.Besides hand muscle strength assessment, currently used muscle function assessments include simple instrumental test, isokinetic muscle test, electrophysiological test, etc.In addition, the application of needle electromyography, motor unit number estimation, motion unit index in muscle function evaluation has also been reported for several times.This paper reviews the research progress and practical application of these methods.

Assessment of the Original Height of L1~2 after Vertebral Compression Fracture / 法医学杂志

OBJECTIVES@#To explore the assessment method of original height of L1-2 after vertebral compression fracture and its application value in forensic clinical practice.@*METHODS@#A total of 154 normal thoracic and lumbar X-ray films were collected, and 140 cases were used as experimental group while 14 cases as validation group. The heights of anterior （Ha） and posterior （Hp） vertebral body of T₁₂-L₃ vertebrae in each X-ray image were measured. In the experimental group, the correlation analysis between HaL₁ and HaT₁₂, HpT₁₂, HpL₁, HaL₂ and HpL₂ was carried out, and regression equation was established via fitting. The correlation analysis between HaL₂ and HaL₁, HpL₁, HpL₂, HaL₃, HpL₃ was performed, and the regression equation was also established via fitting. The difference between the predicted and measured values of HaL₁ and HaL₂ in validation group was compared.@*RESULTS@#In the 140 normal subjects, HaL₁ （y₁） was well correlated with HaT₁₂ （x₁） and HaL₂（x₂）, and the multiple linear regression equation was y₁=2.545+0.423 x₁+0.486 x₂ （determining coefficient R²=0.712, P<0.05; F=169.206, P<0.05）. There was no significant difference between the predicted and actual measured values of HaL₁ in the validation group （ P>0.05）. HaL₂ （y₂） was well correlated with HaL₁ （x₃） and HaL₃ （x₄）, and the multiple linear regression equation was y₂=4.354+0.530 x₃+0.349 x₄ （determining coefficient R²=0.689, P<0.05; F=151.575, P<0.05）. There was no significant difference between the predicted and actual measured values of HaL₂ in the validation group （ P>0.05）.@*CONCLUSIONS@#It is more appropriate to evaluate the original height of L₁ or L₂ single vertebrae by comparing with the height of the anterior edge of the upper and lower adjacent vertebral bodies.

Comparison of Measurement Methods of Exophthalmos and Its Forensic Significance / 法医学杂志

Objective To compare the differences between Hertel exophthalmometry and CT on exophthalmos measurement,and explore its practical application value in forensic medicine.Methods Fifty-six normal individuals without eye injuries or diseases were selected as the control group.The absolute values of exophthalmos were measured in the standardized CT image workstation.The difference of binocular exophthalmos was compared in normal group.Forty-seven cases with unilateral orbital fracture were divided into injured eye group and normal eye group according to the presence of binocular orbital fractures.The differences of the absolute values of eophthalmos from the same eye and the relative values of eophthalmos between two eyes for same person measured by Hertel exophthalmometry and CT were analyzed.Results There was no statistical difference of exophthalmos between the normal eyes measured by CT method.In the normal eye group,the absolute value of exophthalmos measured by CT method was (16.66±5.41) rm,which was (16.16±4.45)mm when measured by the Hertel exophthalmometry method.There was no statistical difference between two groups (P＞0.05).In the injured eye group,there was statistical difference between the absolute values of exophthalmos measured by two measurement methods (P＜0.05).There was no statistical difference of the relative values of exophthalmos between the injured eyes and the normal eyes by two measurement methods (P＞0.05).Conclusion CT method has a good consistency with Hertel exophthalmometry,which can be applied into the practice of medicolegal expertise.