BACK TOTOP Browse A-ZSearchBrowse A-ZABCDEFGHIJKLMNOPQRSTUVWXYZ0-9 E-mail FormEmail ResultsName:Email address:Recipients Name:Recipients address:Message: Print-FriendlyBookmarksbookmarks-menuElectromyographyEMG; Myogram; ElectromyogramElectromyography (EMG) is a test that checks the health of the muscles and the nerves that control the muscles. How the Test is Performed The health care provider inserts a very thin needle electrode through the skin into the muscle. The electrode on the needle picks up the electrical activity given off by your muscles. This activity appears on a nearby monitor and may be heard through a speaker.After placement of the electrodes, you may be asked to contract the muscle. For example, by bending your arm. The electrical activity seen on the monitor provides information about your muscle's ability to respond when the nerves to your muscles are stimulated.A nerve conduction velocity test is almost always performed during the same visit as an EMG. The velocity test is done to see how fast electrical signals move through a nerve.Nerve conduction velocityNerve conduction velocity (NCV) is a test to see how fast electrical signals move through a nerve. This test is done along with electromyography (EM...ImageRead Article Now Book Mark Article How to Prepare for the Test No special preparation is usually necessary. Avoid using any creams or lotions on the day of the test.Body temperature can affect the results of this test. If it is extremely cold outside, you may be told to wait in a warm room for a while before the test is performed.If you are taking blood thinners or anticoagulants, inform the provider performing the test before it is done. How the Test will Feel You may feel some pain or discomfort when the needles are inserted. But most people are able to complete the test without problems.Afterward, the muscle may feel tender or bruised for a few days. Why the Test is Performed EMG is most often used when a person has symptoms of weakness, pain, or abnormal sensation. It can help tell the difference between muscle weakness caused by the injury of a nerve attached to a muscle, and weakness due to nervous system disorders, such as muscle diseases. Normal Results There is normally very little electrical activity in a muscle while at rest. Inserting the needles can cause some electrical activity, but once the muscles quiet down, there should be little electrical activity detected.When you flex a muscle, activity begins to appear. As you contract your muscle more, the electrical activity increases and a pattern can be seen. This pattern helps your doctor determine if the muscle is responding as it should. What Abnormal Results Mean An EMG can detect problems with your muscles during rest or activity. Disorders or conditions that cause abnormal results include the following:Alcoholic neuropathy (damage to nerves from drinking too much alcohol) Alcoholic neuropathyAlcoholic neuropathy is damage to the nerves that results from excessive drinking of alcohol.ImageRead Article Now Book Mark Article Amyotrophic lateral sclerosis (ALS; disease of the nerve cells in the brain and spinal cord that control muscle movement) Amyotrophic lateral sclerosisAmyotrophic lateral sclerosis, or ALS, is a disease of the nerve cells in the brain, brain stem and spinal cord that control voluntary muscle movemen...ImageRead Article Now Book Mark Article Axillary nerve dysfunction (damage of the nerve that controls shoulder movement and sensation) Axillary nerve dysfunctionAxillary nerve dysfunction is nerve damage that can lead to a loss of movement or sensation in the shoulder.ImageRead Article Now Book Mark Article Becker muscular dystrophy (muscle weakness of the legs and pelvis) Becker muscular dystrophyBecker muscular dystrophy is an inherited disorder that involves slowly worsening muscle weakness of the legs and pelvis.ImageRead Article Now Book Mark Article Brachial plexopathy (problem affecting the set of nerves that leave the neck and enter the arm) Brachial plexopathyBrachial plexopathy is a form of peripheral neuropathy. It occurs when there is damage to the brachial plexus. This is a group of nerves that run f...ImageRead Article Now Book Mark Article Carpal tunnel syndrome (problem affecting the median nerve in the wrist and hand) Carpal tunnel syndromeCarpal tunnel syndrome is a condition in which there is excessive pressure on the median nerve at the wrist. This is the nerve that allows feeling a...ImageRead Article Now Book Mark Article Cubital tunnel syndrome (problem affecting the ulnar nerve in the elbow) Cubital tunnel syndromeUlnar nerve dysfunction is a problem with one of the nerves that travel from the shoulder to the hand, called the ulnar nerve. It helps you move you...ImageRead Article Now Book Mark Article Cervical spondylosis (neck pain from wear on the disks and bones of the neck) Cervical spondylosisCervical spondylosis is a disorder in which there is wear on the cartilage (disks) and bones of the neck (cervical vertebrae). It is a common cause ...ImageRead Article Now Book Mark Article Common peroneal nerve dysfunction (damage of the peroneal nerve leading to loss of movement or sensation in the foot and leg) Common peroneal nerve dysfunctionCommon peroneal nerve dysfunction is due to damage to the peroneal nerve leading to loss of movement or sensation in the foot and leg. This conditio...ImageRead Article Now Book Mark Article Denervation (reduced nerve stimulation of a muscle) Dermatomyositis (muscle disease that involves inflammation and a skin rash) DermatomyositisDermatomyositis is a disease that involves muscle inflammation and a skin rash. Polymyositis is a similar inflammatory condition that also involves ...ImageRead Article Now Book Mark Article Distal median nerve dysfunction (problem affecting the median nerve in the arm) Distal median nerve dysfunctionDistal median nerve dysfunction is a form of peripheral neuropathy that affects the movement of or sensation in the hands. A common type of distal me...ImageRead Article Now Book Mark Article Duchenne muscular dystrophy (inherited disease that involves muscle weakness) Duchenne muscular dystrophyDuchenne muscular dystrophy is an inherited disorder. It involves muscle weakness, which quickly gets worse.ImageRead Article Now Book Mark Article Facioscapulohumeral muscular dystrophy (Landouzy-Dejerine; disease of muscle weakness and loss of muscle tissue) Facioscapulohumeral muscular dystrophyFacioscapulohumeral muscular dystrophy is a condition that causes muscle weakness and loss of muscle tissue that gets worse over time.ImageRead Article Now Book Mark Article Familial periodic paralysis (disorder that causes muscle weakness and sometimes a lower than normal level of potassium in the blood) Familial periodic paralysisHypokalemic periodic paralysis (hypoPP) is a disorder that causes occasional episodes of muscle weakness and sometimes a lower than normal level of p...Read Article Now Book Mark Article Femoral nerve dysfunction (loss of movement or sensation in parts of the legs due to damage to the femoral nerve) Femoral nerve dysfunctionFemoral nerve dysfunction is a loss of movement or sensation in parts of the legs due to damage to the femoral nerve.ImageRead Article Now Book Mark Article Friedreich ataxia (inherited disease that affects areas in the brain and spinal cord that control coordination, muscle movement, and other functions) Friedreich ataxiaFriedreich ataxia is a rare disease passed down through families (inherited). It affects the muscles and heart.ImageRead Article Now Book Mark Article Guillain-Barré syndrome (autoimmune disorder of the nerves that leads to muscle weakness or paralysis) Guillain-BarréGuillain-Barré syndrome (GBS) is a serious health problem that occurs when the body's defense (immune) system mistakenly attacks part of the peripher...ImageRead Article Now Book Mark Article Lambert-Eaton syndrome (autoimmune disorder of the nerves that causes muscle weakness) Lambert-Eaton syndromeLambert-Eaton myasthenic syndrome (LEMS) is a rare disorder in which faulty communication between nerves and muscles leads to muscle weakness....ImageRead Article Now Book Mark Article Multiple mononeuropathy (a nervous system disorder that involves damage to at least 2 separate nerve areas) Multiple mononeuropathyMultiple mononeuropathy is a nervous system disorder that involves damage to at least two separate nerve areas. Neuropathy means damage to a periphe...ImageRead Article Now Book Mark Article Mononeuropathy (damage to a single nerve that results in loss of movement, sensation, or other function of that nerve) MononeuropathyMononeuropathy is damage to a single nerve, which results in loss of movement, sensation, or other function of that nerve.ImageRead Article Now Book Mark Article Myopathy (muscle degeneration caused by a number of disorders, including muscular dystrophy) Muscular dystrophyMuscular dystrophy (MD) is a group of inherited disorders that cause muscle weakness and loss of muscle tissue, which get worse over time.ImageRead Article Now Book Mark Article Myasthenia gravis (autoimmune disorder of the nerves that causes weakness of the voluntary muscles) Myasthenia gravisMyasthenia gravis is a neuromuscular disorder. Neuromuscular disorders involve the muscles and the nerves that control them.ImageRead Article Now Book Mark Article Peripheral neuropathy (damage of nerves away from the brain and spinal cord) Peripheral neuropathyPeripheral nerves carry information to and from the brain. They also carry signals to and from the spinal cord to the rest of the body. Peripheral n...ImageRead Article Now Book Mark Article Polymyositis (muscle weakness, swelling, tenderness, and tissue damage of the skeletal muscles) PolymyositisPolymyositis and dermatomyositis are rare inflammatory diseases. (The condition is called dermatomyositis when it involves the skin. ) These disease...ImageRead Article Now Book Mark Article Radial nerve dysfunction (damage of the radial nerve causing loss of movement or sensation in the back of the arm or hand) Radial nerve dysfunctionRadial nerve dysfunction is a problem with the radial nerve. This is the nerve that travels from the armpit down the back of the arm to the hand. I...ImageRead Article Now Book Mark Article Sciatic nerve dysfunction (injury to or pressure on the sciatic nerve that causes weakness, numbness, or tingling in the leg) Sciatic nerve dysfunctionSciatica refers to pain, weakness, numbness, or tingling in the leg. It is caused by injury to or pressure on the sciatic nerve. Sciatica is a symp...ImageRead Article Now Book Mark Article Sensorimotor polyneuropathy (condition that causes a decreased ability to move or feel because of nerve damage) Sensorimotor polyneuropathySensorimotor polyneuropathy is a condition that causes a decreased ability to move and feel (sensation) because of nerve damage.ImageRead Article Now Book Mark Article Shy-Drager syndrome (nervous system disease that causes bodywide symptoms) Shy-Drager syndromeMultiple system atrophy- parkinsonian type (MSA-P) is a rare condition that causes symptoms similar to Parkinson disease. However, people with MSA-P...ImageRead Article Now Book Mark Article Thyrotoxic periodic paralysis (muscle weakness from high levels of thyroid hormone) Thyrotoxic periodic paralysisThyrotoxic periodic paralysis (TPP) is a condition with episodes of severe muscle weakness. It occurs in people who have high levels of thyroid horm...ImageRead Article Now Book Mark Article Tibial nerve dysfunction (damage of the tibial nerve causing loss of movement or sensation in the foot)Tibial nerve dysfunctionTarsal tunnel syndrome is a condition in which the tibial nerve is being compressed. This is the nerve in the ankle that allows feeling and movement...Read Article Now Book Mark Article Risks Risks of this test include:Bleeding (minimal) Infection at the electrode sites (rare)Open ReferencesReferencesChernecky CC, Berger BJ. Electromyography (EMG) and nerve conduction studies (electromyelogram) - diagnostic. 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, eds. Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022 :chap 36.AllVideoImagesTogElectromyography - illustration Electromyography is a test that measures muscle response to nervous stimulation. A needle electrode is inserted through the skin into the muscle. Each muscle fiber that contracts will produce an action potential. The presence, size, and shape of the wave form of the action potential produced on the oscilloscope, provides information about the ability of the muscle to respond to nervous stimulation.ElectromyographyillustrationElectromyography - illustration Electromyography is a test that measures muscle response to nervous stimulation. A needle electrode is inserted through the skin into the muscle. Each muscle fiber that contracts will produce an action potential. The presence, size, and shape of the wave form of the action potential produced on the oscilloscope, provides information about the ability of the muscle to respond to nervous stimulation.Electromyographyillustration Tests for Electromyography ElectromyographyRelated Information Polymyositis - adult(Condition)Carpal tunnel syndrome(Condition)Amyotrophic lateral sclerosis (ALS)(Condition)Muscular dystrophy(Condition)Myasthenia gravis(Condition)Alcoholic neuropathy(Condition)Axillary nerve dysfunction(Condition)Becker muscular dystrophy(Condition)Brachial plexopathy(Condition)Cervical spondylosis(Condition)Carpal tunnel syndrome - InDepth(In-Depth)Back pain and sciatica - InDepth(In-Depth) Review Date: 5/2/2022 Reviewed By: Amit M. Shelat, DO, FACP, FAAN, Attending Neurologist and Assistant Professor of Clinical Neurology, Renaissance School of Medicine at Stony Brook University, Stony Brook, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, timeliness, or correctness of any translations made by a third-party service of the information provided herein into any other language. © 1997- A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited. © 1997- All rights reserved. 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ElectromyographyEMG; Myogram; ElectromyogramElectromyography (EMG) is a test that checks the health of the muscles and the nerves that control the muscles. How the Test is Performed The health care provider inserts a very thin needle electrode through the skin into the muscle. The electrode on the needle picks up the electrical activity given off by your muscles. This activity appears on a nearby monitor and may be heard through a speaker.After placement of the electrodes, you may be asked to contract the muscle. For example, by bending your arm. The electrical activity seen on the monitor provides information about your muscle's ability to respond when the nerves to your muscles are stimulated.A nerve conduction velocity test is almost always performed during the same visit as an EMG. The velocity test is done to see how fast electrical signals move through a nerve.Nerve conduction velocityNerve conduction velocity (NCV) is a test to see how fast electrical signals move through a nerve. This test is done along with electromyography (EM...ImageRead Article Now Book Mark Article How to Prepare for the Test No special preparation is usually necessary. Avoid using any creams or lotions on the day of the test.Body temperature can affect the results of this test. If it is extremely cold outside, you may be told to wait in a warm room for a while before the test is performed.If you are taking blood thinners or anticoagulants, inform the provider performing the test before it is done. How the Test will Feel You may feel some pain or discomfort when the needles are inserted. But most people are able to complete the test without problems.Afterward, the muscle may feel tender or bruised for a few days. Why the Test is Performed EMG is most often used when a person has symptoms of weakness, pain, or abnormal sensation. It can help tell the difference between muscle weakness caused by the injury of a nerve attached to a muscle, and weakness due to nervous system disorders, such as muscle diseases. Normal Results There is normally very little electrical activity in a muscle while at rest. Inserting the needles can cause some electrical activity, but once the muscles quiet down, there should be little electrical activity detected.When you flex a muscle, activity begins to appear. As you contract your muscle more, the electrical activity increases and a pattern can be seen. This pattern helps your doctor determine if the muscle is responding as it should. What Abnormal Results Mean An EMG can detect problems with your muscles during rest or activity. Disorders or conditions that cause abnormal results include the following:Alcoholic neuropathy (damage to nerves from drinking too much alcohol) Alcoholic neuropathyAlcoholic neuropathy is damage to the nerves that results from excessive drinking of alcohol.ImageRead Article Now Book Mark Article Amyotrophic lateral sclerosis (ALS; disease of the nerve cells in the brain and spinal cord that control muscle movement) Amyotrophic lateral sclerosisAmyotrophic lateral sclerosis, or ALS, is a disease of the nerve cells in the brain, brain stem and spinal cord that control voluntary muscle movemen...ImageRead Article Now Book Mark Article Axillary nerve dysfunction (damage of the nerve that controls shoulder movement and sensation) Axillary nerve dysfunctionAxillary nerve dysfunction is nerve damage that can lead to a loss of movement or sensation in the shoulder.ImageRead Article Now Book Mark Article Becker muscular dystrophy (muscle weakness of the legs and pelvis) Becker muscular dystrophyBecker muscular dystrophy is an inherited disorder that involves slowly worsening muscle weakness of the legs and pelvis.ImageRead Article Now Book Mark Article Brachial plexopathy (problem affecting the set of nerves that leave the neck and enter the arm) Brachial plexopathyBrachial plexopathy is a form of peripheral neuropathy. It occurs when there is damage to the brachial plexus. This is a group of nerves that run f...ImageRead Article Now Book Mark Article Carpal tunnel syndrome (problem affecting the median nerve in the wrist and hand) Carpal tunnel syndromeCarpal tunnel syndrome is a condition in which there is excessive pressure on the median nerve at the wrist. This is the nerve that allows feeling a...ImageRead Article Now Book Mark Article Cubital tunnel syndrome (problem affecting the ulnar nerve in the elbow) Cubital tunnel syndromeUlnar nerve dysfunction is a problem with one of the nerves that travel from the shoulder to the hand, called the ulnar nerve. It helps you move you...ImageRead Article Now Book Mark Article Cervical spondylosis (neck pain from wear on the disks and bones of the neck) Cervical spondylosisCervical spondylosis is a disorder in which there is wear on the cartilage (disks) and bones of the neck (cervical vertebrae). It is a common cause ...ImageRead Article Now Book Mark Article Common peroneal nerve dysfunction (damage of the peroneal nerve leading to loss of movement or sensation in the foot and leg) Common peroneal nerve dysfunctionCommon peroneal nerve dysfunction is due to damage to the peroneal nerve leading to loss of movement or sensation in the foot and leg. This conditio...ImageRead Article Now Book Mark Article Denervation (reduced nerve stimulation of a muscle) Dermatomyositis (muscle disease that involves inflammation and a skin rash) DermatomyositisDermatomyositis is a disease that involves muscle inflammation and a skin rash. Polymyositis is a similar inflammatory condition that also involves ...ImageRead Article Now Book Mark Article Distal median nerve dysfunction (problem affecting the median nerve in the arm) Distal median nerve dysfunctionDistal median nerve dysfunction is a form of peripheral neuropathy that affects the movement of or sensation in the hands. A common type of distal me...ImageRead Article Now Book Mark Article Duchenne muscular dystrophy (inherited disease that involves muscle weakness) Duchenne muscular dystrophyDuchenne muscular dystrophy is an inherited disorder. It involves muscle weakness, which quickly gets worse.ImageRead Article Now Book Mark Article Facioscapulohumeral muscular dystrophy (Landouzy-Dejerine; disease of muscle weakness and loss of muscle tissue) Facioscapulohumeral muscular dystrophyFacioscapulohumeral muscular dystrophy is a condition that causes muscle weakness and loss of muscle tissue that gets worse over time.ImageRead Article Now Book Mark Article Familial periodic paralysis (disorder that causes muscle weakness and sometimes a lower than normal level of potassium in the blood) Familial periodic paralysisHypokalemic periodic paralysis (hypoPP) is a disorder that causes occasional episodes of muscle weakness and sometimes a lower than normal level of p...Read Article Now Book Mark Article Femoral nerve dysfunction (loss of movement or sensation in parts of the legs due to damage to the femoral nerve) Femoral nerve dysfunctionFemoral nerve dysfunction is a loss of movement or sensation in parts of the legs due to damage to the femoral nerve.ImageRead Article Now Book Mark Article Friedreich ataxia (inherited disease that affects areas in the brain and spinal cord that control coordination, muscle movement, and other functions) Friedreich ataxiaFriedreich ataxia is a rare disease passed down through families (inherited). It affects the muscles and heart.ImageRead Article Now Book Mark Article Guillain-Barré syndrome (autoimmune disorder of the nerves that leads to muscle weakness or paralysis) Guillain-BarréGuillain-Barré syndrome (GBS) is a serious health problem that occurs when the body's defense (immune) system mistakenly attacks part of the peripher...ImageRead Article Now Book Mark Article Lambert-Eaton syndrome (autoimmune disorder of the nerves that causes muscle weakness) Lambert-Eaton syndromeLambert-Eaton myasthenic syndrome (LEMS) is a rare disorder in which faulty communication between nerves and muscles leads to muscle weakness....ImageRead Article Now Book Mark Article Multiple mononeuropathy (a nervous system disorder that involves damage to at least 2 separate nerve areas) Multiple mononeuropathyMultiple mononeuropathy is a nervous system disorder that involves damage to at least two separate nerve areas. Neuropathy means damage to a periphe...ImageRead Article Now Book Mark Article Mononeuropathy (damage to a single nerve that results in loss of movement, sensation, or other function of that nerve) MononeuropathyMononeuropathy is damage to a single nerve, which results in loss of movement, sensation, or other function of that nerve.ImageRead Article Now Book Mark Article Myopathy (muscle degeneration caused by a number of disorders, including muscular dystrophy) Muscular dystrophyMuscular dystrophy (MD) is a group of inherited disorders that cause muscle weakness and loss of muscle tissue, which get worse over time.ImageRead Article Now Book Mark Article Myasthenia gravis (autoimmune disorder of the nerves that causes weakness of the voluntary muscles) Myasthenia gravisMyasthenia gravis is a neuromuscular disorder. Neuromuscular disorders involve the muscles and the nerves that control them.ImageRead Article Now Book Mark Article Peripheral neuropathy (damage of nerves away from the brain and spinal cord) Peripheral neuropathyPeripheral nerves carry information to and from the brain. They also carry signals to and from the spinal cord to the rest of the body. Peripheral n...ImageRead Article Now Book Mark Article Polymyositis (muscle weakness, swelling, tenderness, and tissue damage of the skeletal muscles) PolymyositisPolymyositis and dermatomyositis are rare inflammatory diseases. (The condition is called dermatomyositis when it involves the skin. ) These disease...ImageRead Article Now Book Mark Article Radial nerve dysfunction (damage of the radial nerve causing loss of movement or sensation in the back of the arm or hand) Radial nerve dysfunctionRadial nerve dysfunction is a problem with the radial nerve. This is the nerve that travels from the armpit down the back of the arm to the hand. I...ImageRead Article Now Book Mark Article Sciatic nerve dysfunction (injury to or pressure on the sciatic nerve that causes weakness, numbness, or tingling in the leg) Sciatic nerve dysfunctionSciatica refers to pain, weakness, numbness, or tingling in the leg. It is caused by injury to or pressure on the sciatic nerve. Sciatica is a symp...ImageRead Article Now Book Mark Article Sensorimotor polyneuropathy (condition that causes a decreased ability to move or feel because of nerve damage) Sensorimotor polyneuropathySensorimotor polyneuropathy is a condition that causes a decreased ability to move and feel (sensation) because of nerve damage.ImageRead Article Now Book Mark Article Shy-Drager syndrome (nervous system disease that causes bodywide symptoms) Shy-Drager syndromeMultiple system atrophy- parkinsonian type (MSA-P) is a rare condition that causes symptoms similar to Parkinson disease. However, people with MSA-P...ImageRead Article Now Book Mark Article Thyrotoxic periodic paralysis (muscle weakness from high levels of thyroid hormone) Thyrotoxic periodic paralysisThyrotoxic periodic paralysis (TPP) is a condition with episodes of severe muscle weakness. It occurs in people who have high levels of thyroid horm...ImageRead Article Now Book Mark Article Tibial nerve dysfunction (damage of the tibial nerve causing loss of movement or sensation in the foot)Tibial nerve dysfunctionTarsal tunnel syndrome is a condition in which the tibial nerve is being compressed. This is the nerve in the ankle that allows feeling and movement...Read Article Now Book Mark Article Risks Risks of this test include:Bleeding (minimal) Infection at the electrode sites (rare)Open ReferencesReferencesChernecky CC, Berger BJ. Electromyography (EMG) and nerve conduction studies (electromyelogram) - diagnostic. 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, eds. Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022 :chap 36.