The document provides information about electromyography (EMG), including: 1. EMG measures muscle electrical activity in response to nerve stimulation by inserting small needles into muscles. Electrodes detect activity which is displayed as waves. 2. It is used to detect neuromuscular abnormalities and indicates conditions like nerve damage, inflammation, or muscle disease. Abnormal results can show damage to axons or myelin sheaths. 3. The procedure involves inserting needles into a muscle to be tested and having the patient contract their muscle while electrical activity is measured. Normal results show no activity at rest while abnormal results show spontaneous activity or irregular contraction patterns.

1. Presenter- Guided by-
Dr. Twinkle Joshi Dr. Vaishali Kuchewar
PG Scholar Prof, Dept. of Kayachikitsa
Electromyogram

2. Introduction
 Electromyography (EMG) measures muscle response or
electrical activity in response to a nerve’s stimulation.
 Measures electrical activity of muscle during rest, slight or
forceful contraction
 Normally - no electrical signals are produced at rest.
 Shows ability of the muscle to respond when the nerves are
stimulated.
 Detects neuromuscular abnormalities

3.  In the test, small needles (electrodes) are inserted through
the skin into the muscle.
 Electrodes detect electrical activity and display on the
oscilloscope in the form of waves.
 Audio-amplifier can be used to hear the activity .
 Commonly tested nerves-
Upper extremities- Radial, Ulnar nerve
Lower extremities- Peroneal, Tibial nerve

4. Indications
 Tingling, Numbness
 Muscle weakness, pain or cramps
 Brachial plexopathy
 Cervical spondylosis
 DMD, BMD
 Myasthenia gravis
 Carpal tunnel syndrome or peripheral neuropathies
 Amyotrophic lateral sclerosis or polio
 Herniated disk in the spine

5. Before the test
 Avoid caffeinated beverages, such as coffee, tea, etc 2-3 hrs
before testing.
 Stop using lotions or oils on skin
 Prior notification – pacemaker, blood-thinning medications
 Wear clothes that permit access to the area to be tested
 Remove jewelry,pins,glasses, hearing aids, or metal objects
 Nerve conduction study is done (measures flow of current
through a nerve before it reaches the muscle)

6. Sit/ lie down
locate the muscle to
be studied.
clean the skin
with antiseptic
solution
5 or more sterile
needles are inserted
into muscle
ground electrode is kept
under arm/leg
perform slight/full-
strength muscle
contraction
electrical activity is
measured &
displayed on
oscilloscope.
audio
amplifier
evaluates
appearance
and sound of
electrical
potentials
Procedure

7. Interpretation
 Amplitude: Height of the wave
 Conduction velocity (CV): speed at which electrical impulse
travels along the nerve.
 Duration: width of electrical wave.
 Conduction block: reduction of a signal in an anatomical
region, such as wrist due to carpal tunnel syndrome
 F reflex: impulse travels up to the spine and then back down
along the same fiber. It shows conduction along the motor
nerve(electrical echo)
 H reflex: impulse travels to the spinal cord via a sensory nerve,
then back along a motor nerve.

8.  Gives information about both motor and sensory
components of PNS.
 Shows whether the axon or myelin sheath is damaged by
a neuropathy.
 Myelin helps action potentials travel faster, and so in
problems of myelin (myelinopathy), conduction velocity is
decreased.
 In axon (axonopathy),fibers that are intact can conduct
signals at normal speeds, but there are fewer fibers,
which leads to a weaker signal and decreased amplitude.

9.  Normal EMG: When muscles are
at rest, they produce no or
very little electrical activity.
 Activity at rest:
 In diseases of peripheral nerves,
like carpal tunnel syndrome and
peripheral neuropathy, muscles
show spontaneous activity on their own, which indicates
altered nerve supply.
 It also points to inflammation or a muscle disease.
 Depicted as fibrillations and positive sharp deflections.

10.  Abnormal activity during contraction: “Recruitment pattern"
As muscle is contracted, nerve fibers signal more and more
bits of muscle (called motor units) to join in and help.
 In peripheral nerve diseases, the nerve is unable to connect to
many units.
 NCS results: Abnormal NCS result occurs due to
conduction block,
axonopathy (the nerve fiber is damaged), or
demyelination (damage to the outer insulating layer of
nerves)

11. Contra Indications
 Patients on anticoagulation or antiplatelet therapy.
 Paraspinal muscles are avoided in patients on
anticoagulation due to potential possibility of hematoma
formation adjacent to spinal structures.
 In overlying skin infection
 Limb affected with lymphedema
 Pacemakers, internal defibrillators

12. Complications
 Complications rare.
 Risk of bleeding, infection and nerve injury due to
needle electrode
 Muscle soreness
 Pain, tenderness, swelling, or pus at the needle
insertion sites.
 Pneumothorax

13. Thank you!

14. Thought of the day