Definition: an electromyogram (EMG) looks at the function of the nerve roots that leave the spinal column.
This is done by observing how electrical currents are transmitted from the nerves to the muscles.
The pressure on the nerves or damage to them changes how the muscles transmit the electrical current as they react to the information sent to them from the brain by the nerves.
By ordering this test to diagnose problems in the spine, it is combined with a test that shows the electrical signals that go from the body to the brain.
Why is it done?
In search of abnormal electrical signals in the muscles, the EMG can tell your doctor if a nerve is irritated or pinched.
For example, if a bulb is placed on the lamp and illuminated, it can be assumed that the wiring is OK, but if the bulb does not turn on, you might consider that something is probably wrong with the wiring.
The EMG can determine the state of the nerves that innervate the muscles, so your doctor may consider that these should be found pinching or compressing somewhere.
How is an Electromyogram done?
Small electrodes are inserted into the muscles of the legs, where the nerve that goes to each power is stimulated to observe then how long it takes the electrical signal to reach the strength and cause it to contract. The procedure takes about 2 to 3 hours to complete.
What are the limitations?
An Electromyogram does not show why there is a problem with the nerves in the spine or what is causing it. The test mainly looks at how your muscles react to the nerve problem, including determining that they can not be in the same place.
Another limitation of the EMG is that the test result may be expected when the nerve is damaged. This is called a “false positive,” The results of the tests look positive even though the nerve is negative.