Home

electromyografie

Electromyography (EMG) is a diagnostic technique for evaluating and recording the electrical activity produced by skeletal muscles and the nerves that control them. EMG helps diagnose neuromuscular disorders, assess muscle function, and guide rehabilitation. In practice, EMG can be performed with surface electrodes that measure activity from broad muscle regions (surface EMG) or with fine needles inserted into a specific muscle (intramuscular or needle EMG). Nerve conduction studies (NCS) are commonly performed together with EMG to test the integrity of peripheral nerves.

During needle EMG, a clinician inserts a needle electrode into muscle and records motor unit action potentials

Interpretation: Findings can indicate denervation, reinnervation, myopathy, or neuropathy. For example, abnormal spontaneous activity at rest

Applications: diagnosis of radiculopathy and peripheral neuropathies, motor neuron disease, myopathies, and neuromuscular junction disorders; assessment

Limitations and safety: needle EMG can cause transient discomfort and carries minor risks of bleeding or infection;

during
rest
and
during
voluntary
contraction.
Surface
EMG
records
the
summed
electrical
activity
of
many
motor
units,
often
used
to
study
movement
patterns
in
research
and
sports
medicine.
Data
are
analyzed
for
timing,
amplitude,
frequency
content,
recruitment
patterns,
and
the
presence
of
spontaneous
activity
such
as
fibrillations
or
positive
sharp
waves.
suggests
nerve
injury;
decreased
recruitment
and
large,
polyphasic
motor
unit
potentials
imply
chronic
reinnervation;
reduced
amplitude
indicates
myopathic
disease.
However,
EMG
results
must
be
interpreted
in
the
context
of
symptoms
and
other
tests.
of
muscle
function
in
rehabilitation,
ergonomics,
and
sports
medicine;
neurophysiological
research
and
biofeedback.
surface
EMG
can
be
affected
by
skin
impedance,
adipose
tissue,
and
cross-talk
from
nearby
muscles.
EMG
interpretation
requires
trained
clinicians
and
is
one
component
of
a
broader
clinical
assessment.