Electromyography (EMG)


Electromyography is a test that measures and records the activity of contracting muscles in response to electrical stimulation. It checks the health of the muscles and the nerves that control the muscles. EMG is performed using an instrument called electromyogaph, to produce a record called an electromyogram.

Purpose of EMG

  • EMGs are useful in determining the presence of a neuromuscular disorder and neuropathies.
  • Helps to distinguish weakness due to neuropathy (functional or pathologic changes in the peripheral nervous system) from weakness due to other causes.
  • It helps differentiate muscle disease from motor neuron dysfunction.

How EMG is performed

  1. A very thin needle electrode will be inserted through the skin of the patient to the muscle. The electrode on the needle picks up the electrical activity given off by the muscles. Muscular activity is monitored on a nearby apparatus with a screen and may be heard through a speaker.
  2. Once the electrodes are already in placed, the client is asked to contract the muscle such as by bending his or her arm. The electrical activity seen on the monitor provides information about the muscle’s ability to respond when the nerves on the muscles are stimulated.
  3. Along with EMG a nerve conduction velocity is usually performed.

Before the Procedure

No special patient preparation is required. However, it would be best to do the following:

  1. Explain the procedure to the patient.
  2. Instruct the patient to avoid using any creams or lotions on the day of the test.
  3. Body temperature can affect the results of this test. It is important to tell the patient that if it is extremely cold outside, he or she should wait in a warm room for a while before the test is performed.
  4. Prepare the patient for the discomfort of needle insertion. Inform the patient that he or she will experience a sensation similar to that of an intramuscular injection as the needle is inserted into the muscle.
  5. Notify the client that the muscles examined may ache for a short time after the procedure.

After the Procedure

  1. If the patient is having this test in a doctor’s office, he or she will be sent home following the procedure without any restriction of activities.
  2. Some patient may have minor aches and pains from the testing.


1. Bleeding (minimal)

2. Infection at the electrode sites (minimal risk)

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Daisy Jane Antipuesto RN MN

Currently a Nursing Local Board Examination Reviewer. Subjects handled are Pediatric, Obstetric and Psychiatric Nursing. Previous work experiences include: Clinical instructor/lecturer, clinical coordinator (Level II), caregiver instructor/lecturer, NC2 examination reviewer and staff/clinic nurse. Areas of specialization: Emergency room, Orthopedic Ward and Delivery Room. Also an IELTS passer.

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