Which is the process of recording the electrical potential of skeletal muscles and nerves supplying them by inserting small needle electrodes into the muscles?

Appeared in: RRB Nsg. Superintendent-20 July 2019 (Shift-1)

Explanation

Electromyography (EMG) is the specific diagnostic test that measures the electrical activity of skeletal muscles.
The procedure involves inserting fine-needle electrodes directly into the muscle to record electrical potentials.
This recording helps in diagnosing diseases that affect muscles and nerves, such as muscular dystrophy, myasthenia gravis, and amyotrophic lateral sclerosis (ALS).
The question's description of inserting needle electrodes into muscles to record electrical potential directly matches the definition of an EMG.

Option A: ECT (Electroconvulsive Therapy) is a form of psychiatric treatment, not a diagnostic test for muscle electrical activity. It uses electrical currents to induce a seizure for therapeutic purposes.
Option B: EEG (Electroencephalogram) measures the electrical activity of the brain, not skeletal muscles. It uses electrodes placed on the scalp.
Option C: ECG (Electrocardiogram) measures the electrical activity of the heart, not skeletal muscles. It uses surface electrodes on the chest and limbs.

Visual 1: Diagram - A diagram illustrating the placement of a needle electrode into a skeletal muscle for an EMG, contrasted with surface electrode placement for an EEG and ECG. This helps clarify the key procedural difference.
Visual 2: Infographic - A comparative chart showing the target organ, purpose, and electrode type for EMG, EEG, ECG, and ECT.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Diagnostic neurophysiological procedures as background academic context rather than a clinical decision trigger.
A nurse's role in preparing a patient for an EMG includes explaining the procedure, reassuring the patient that the sensation is similar to an intramuscular injection, and informing them that the muscles may ache for a short time afterward.
The nurse must also check if the patient is on any anticoagulant medication, as the needle insertion carries a risk of bleeding.
What if? If the patient had a pacemaker, an ECG would be a relevant test to assess heart function, but an EMG would still be the correct procedure for muscle-related complaints, though caution would be needed depending on the muscle being tested in proximity to the device.

How to Approach the Question

First, break down the question to identify the key components: the action (recording electrical potential), the target tissue (skeletal muscles and nerves), and the method (inserting small needle electrodes).
Evaluate each option against these key components.
Option A (ECT) is a treatment, not a recording process. Eliminate it.
Option B (EEG) records from the brain, not muscles. Eliminate it.
Option C (ECG) records from the heart, not skeletal muscles. Eliminate it.
Option D (EMG) specifically involves recording electrical signals from muscles using needle electrodes. This matches all parts of the question.

Concept Tested & Keywords

Concept Tested: Diagnostic neurophysiological procedures
Stem keywords: electrical potential, skeletal muscles, nerves, needle electrodes
Lead-in keywords: Which is the process
Negative lead-in flag: false

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Practise the full RRB Nsg. Superintendent-20 July 2019 (Shift-1)

Attempt every question from this paper in a timed mock, then review the full solution for each one.