An EMG study is often used by doctors to determine whether there is peripheral nerve damage, particularly on an individual’s spine. You can have neuropathy in your fingers, and hands, or feet that starts or originates in the spine.
When a disc is damaged, bulged, protrusion, extrusion, or herniation it extends out to the neuroforamen which causes foraminal stenosis. The disc then pushes out to an area where the nerve is exiting from the spinal cord. When the disc touches the nerve it causes symptom to the extremities.
The most common type of that injury is called sciatica, sciatic pain is a very specific problem. Sciatica is when the L5S1 nerve root is affected, people generally get symptoms at the back of their legs. They can test to see if there is a problem, each individual nerve that exits the spinal cord controls a different part of the body. Because our body works on electrical impulses, the testing of those electrical impulses can show if there’s damage.
Doctors use the EMG electromyography to insert small needles and then test the latencies of the way the electricity is firing inside the body. By doing that they can make sure the nerve is being affected. If the nerve is being affected, they will see changes in the test panels. The EMG is a very important tool that doctors use to diagnose these issues. The one thing you need to know about EMGs is that they’re not a fail safe. The problem with the EMG study is that they do provide a number of false negatives. If a person having sciatic pain in a very particular moment and EMG is taken. Then the EMG will show positive. If the symptom stop and the same person is provided with EMG, then the EMG may show negative. The EMG only tests pyramidal nerves, which are the ones that are coming out of the spinal cord. The same symptoms can arise when a person has a disc injury that is actually pushing up against the cord. So if the hands and legs are numb, then the EMG will actually be negative even though they are having the symptoms. This is because it doesn’t test for cord compression, just for pyramidal or exiting nerve compression.