X-rays
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	EMG

What is it?
An Electromyogram (EMG) is a test that uses small needle electrodes, which are inserted into the muscles of the back and/or neck, to determine if nerves serving those muscles are irritated or pinched in some way. The electrodes detect the smallest variation in electrical signals (stimuli), much like you would use a voltage meter to test the wiring system in your home or vehicle. If the porch light on your house were out, you would try to replace the light bulb. If that failed to shed light on the situation, you would most likely check into the wiring in that area of the home. Electromyography is based on a similar philosophy. Small electrodes inserted into a muscle are used to sense any response to electrical stimuli.

Why is it done?
An EMG is most commonly ordered when a patient displays weakness or a decrease in muscle strength. Of course, these symptoms can be the result of a primary muscle condition or, as the EMG will detect, a neurological condition. Electromyography is also effective at helping a doctor determine whether a nerve is degenerated (neuropathy) or compressed (radiculopathy).

What does it involve?
Because it involves placing small needles through the skin and into the muscle, an EMG may result in some minor discomfort for patients. In some cases, several electrodes may be inserted into the same muscle – the number of electrodes used depends on the size of the muscle being tested. Once the electrodes are in place, the patient is asked to contract the muscle, which produces an action potential (At rest or relaxed, muscle tissue is normally electrically inactive – a state that is referred to as resting potential). The presence, size, and shape of the waveform of the action potential produced as a result of the contraction – as observed visually on an oscilloscope or audibly through a speaker – provides a measurement of the muscle's ability to respond to nerve stimulation.

How should I prepare for it?
For an adult patient, taking an EMG requires no special preparation. Insertion of the electrodes may create some minor discomfort, similar to getting an intramuscular injection like those used to administer vaccinations. After the test, the muscles tested may feel tender and may even bruise. Infection and bleeding are potential complications with any injection.

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