What the study looks at
A fine needle electrode is placed in a muscle. The recording looks at how the muscle behaves when the needle is inserted, whether the muscle is quiet at rest, and how motor units fire when the patient contracts. Those findings describe the muscle and the motor nerve that supplies it.
Muscles are chosen to answer the referring question. A study for a suspected radiculopathy samples a different set of muscles than a study for a single entrapment or a suspected muscle disease. There is no single list that fits every patient.
How the visit is performed
The patient is asked to relax, then to tighten the muscle gently. The needle is in place only briefly for each muscle. People usually describe a short ache or pressure, not a shock. The electrical stimulus patients sometimes expect belongs to the nerve conduction portion of the visit, which uses surface electrodes on the skin.
When you schedule, mention a bleeding disorder, anticoagulation that is a concern for your patient, marked swelling, or a skin infection over a muscle that might be examined, so the study can be planned safely.
Atlas brings the EMG instrument and a technician to your office.
Why a practice orders it
Physicians use EMG when weakness, numbness, pain, or atrophy might come from a nerve root, a plexus, a peripheral nerve, the neuromuscular junction, or the muscle itself. The pattern across muscles can help localize the problem. Combined with nerve conduction studies, EMG is often more informative than either study alone.
The tracing is interpreted with the exam. An EMG does not replace imaging or the physician’s diagnosis, and a normal study does not erase a convincing clinical finding.