Electromyography is a diagnostic method that allows you to assess bioelectrical activity of muscles, on the basis of which it can be concluded about the functional state of the nerve that innervates the damaged muscle. This study will help specialist determine the location and extent of the lesion, the severity and nature of muscle and peripheral nerve damage.

Essence of Procedure

This study is carried out using a special apparatus - an electromyograph. Today it is a whole computer system that records the biopotentials of muscles, amplifies them, and then evaluates the data obtained.
Electrodes register muscle potentials and transmit them to an electromyograph. The device amplifies the signal and sends it either to a computer monitor in the form of an image, or to an oscilloscope for subsequent recording on paper.

There are certain norms for the electrical activity of the muscles, indicating their satisfactory function. If the electromyogram readings go beyond these norms, they speak of a disease of the muscle itself or of the peripheral nerve that innervates it.

Types of Electromyography

Depending on the type of electrodes, electromyography is divided into surface (global) and local.
When performing local electromyography, electrode in the form of a thin needle is inserted percutaneously into the thickness of the muscle. This is an invasive technique that is used to study the function of individual muscle elements.
Each type of procedure has its own indications, so the question of which of them should be used is decided individually by the attending physician. Both types of electromyography are often prescribed simultaneously.

How is Electromyography Performed?

The study can be carried out both in a hospital setting and on an outpatient basis. During it, patient is in a comfortable sitting, half-sitting or lying position. Specialist treats the skin areas that will be in contact with the electrodes with antiseptic and applies electrodes connected to an electromyograph on the muscle to be examined. During the insertion of the needle electrode into the muscle, patient feels a mild pain.

At the beginning of the study, the potentials of the relaxed muscle are recorded, after which patient is asked to slowly strain it and at this time the impulses are also recorded.

The resulting record - electromyogram - is assessed by a specialist in the diagnostic room, and then transmits the conclusion to patient or directly to the attending physician.

Often, electromyography is used in conjunction with a similar study of nerve function - electroneurography. These diagnostic methods complement each other and allow specialist to see the complete picture of a particular disease.

Thus, this study is an important instrumental method for diagnosing a patient's health or disease.