Electromyography

Definition

肌电图(EMG)是一项检查肌肉和控制肌肉的神经健康状况的测试.

Alternative Names

EMG; Myogram; Electromyogram

How the Test is Performed

医疗保健提供者将一个非常细的电极针穿过皮肤插入肌肉. 针上的电极会收集你肌肉发出的电活动. 这个活动出现在附近的显示器上，可以通过扬声器听到.

电极放置后，你可能会被要求收缩肌肉. For example, by bending your arm. 监视器上看到的电活动提供了当肌肉神经受到刺激时肌肉反应能力的信息.

A nerve conduction velocity 该测试几乎总是与肌电图在同一就诊期间进行. 速度测试是为了观察电信号在神经中传递的速度.

How to Prepare for the Test

No special preparation is usually necessary. 在考试当天避免使用任何面霜或乳液.

Body temperature can affect the results of this test. If it is extremely cold outside, 你可能会被告知在一个温暖的房间里等待一段时间，然后再进行测试.

If you are taking blood thinners or anticoagulants, 在测试完成之前通知提供商执行测试.

How the Test will Feel

当针头插入时，你可能会感到疼痛或不舒服. 但大多数人都能毫无问题地完成测试.

之后，肌肉可能会在几天内感到柔软或瘀伤.

Why the Test is Performed

肌电图最常用于当一个人有虚弱、疼痛或异常感觉的症状. 它可以帮助区分由与肌肉相连的神经损伤引起的肌肉无力, and weakness due to nervous system disorders, such as muscle diseases.

Normal Results

正常情况下，休息时肌肉的电活动很少. 插入针头会引起一些电活动, but once the muscles quiet down, there should be little electrical activity detected.

When you flex a muscle, activity begins to appear. 当你的肌肉进一步收缩时，电活动会增加，并且可以看到一种模式. 这种模式可以帮助你的十大赌博平台排行榜确定肌肉是否有应有的反应.

What Abnormal Results Mean

肌电图可以检测肌肉在休息或活动时的问题. 导致不正常结果的疾病或状况包括:

• Alcoholic neuropathy (damage to nerves from drinking too much alcohol)
• Amyotrophic lateral sclerosis (ALS; disease of the nerve cells in the brain and spinal cord that control muscle movement)
• Axillary nerve dysfunction (控制肩部运动和感觉的神经受损)
• Becker muscular dystrophy (muscle weakness of the legs and pelvis)
• Brachial plexopathy (影响从颈部进入手臂的神经的问题)
• Carpal tunnel syndrome (影响手腕和手正中神经的问题)
• Cubital tunnel syndrome (problem affecting the ulnar nerve in the elbow)
• Cervical spondylosis (颈部椎间盘和颈部骨骼磨损引起的颈部疼痛)
• Common peroneal nerve dysfunction (腓神经损伤，导致足部和腿部失去运动或感觉)
• Denervation (reduced nerve stimulation of a muscle)
• Dermatomyositis (包括炎症和皮疹的肌肉疾病)
• Distal median nerve dysfunction (problem affecting the median nerve in the arm)
• Duchenne muscular dystrophy (inherited disease that involves muscle weakness)
• Facioscapulohumeral muscular dystrophy (Landouzy-Dejerine; disease of muscle weakness and loss of muscle tissue)
• Familial periodic paralysis (引起肌肉无力，有时血液中钾含量低于正常水平的疾病)
• Femoral nerve dysfunction (由于股神经受损，腿部部分失去运动或感觉)
• Friedreich ataxia 遗传性疾病，影响大脑和脊髓中控制协调的区域, muscle movement, and other functions)
• Guillain-Barré 综合症(导致肌肉无力或瘫痪的神经自身免疫紊乱)
• Lambert-Eaton syndrome (引起肌肉无力的神经自身免疫性疾病)
• Multiple mononeuropathy (一种神经系统紊乱，涉及至少两个独立的神经区域受损)
• Mononeuropathy (对单个神经的损伤，导致失去活动能力, sensation, or other function of that nerve)
• 肌病(由许多疾病引起的肌肉变性，包括 muscular dystrophy)
• Myasthenia gravis (引起随意肌无力的神经自身免疫性疾病)
• Peripheral neuropathy (大脑和脊髓以外的神经受损)
• Polymyositis (肌肉无力、肿胀、压痛和骨骼肌组织损伤)
• Radial nerve dysfunction (桡神经损伤，导致手臂或手背失去运动或感觉)
• Sciatic nerve dysfunction (坐骨神经受伤或受压，导致腿部无力、麻木或刺痛)
• Sensorimotor polyneuropathy (由于神经损伤导致移动能力或感觉能力下降的一种状态)
• Shy-Drager syndrome (引起全身症状的神经系统疾病)
• Thyrotoxic periodic paralysis (muscle weakness from high levels of thyroid hormone)
• Tibial nerve dysfunction (胫骨神经受损，导致足部失去运动或感觉)

Risks

Risks of this test include:

• Bleeding (minimal)
• Infection at the electrode sites (rare)

References

Chernecky CC, Berger BJ. 肌电图(EMG)和神经传导研究(髓电图)-诊断. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures. 6th ed. St Louis, MO: Elsevier Saunders; 2013:468-469.

Katirji B. Clinical electromyography. In: Jankovic J, Mazziotta JC, Pomeroy SL, Newman NJ，编辑. Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022 :chap 36.