Electromyography Flashcards
Define Electromyography. 3 parts.
A diagnostic test that assesses the health of the muscles and the nerves controlling the muscles. (when is the muscle contracting? provides assurance it’s working)
A tool used by kinesiologists for research of muscle function.
A tool used by PTs to facilitate or inhibit muscle contraction.
How is EMG or Myogram performed?
A needle electrode is inserted through the skin into the muscle or a surface electrode is placed on the skin overlying a muscle. The electrical activity of the muscle detected y this electrode is displayed on an oscilloscope or may be heard through a speaker.
Define a muscle fiber.
Aka muscle cell…When adequately stimulated by a motor neuron (or an outside simulus like an electric stim machine), will produce an action potential (bioelectric current) along/through its various membranes.
How do action potentials relate to EMG?
Action potentials can be detected with machines sensitive to electric current. For example, and ECG detects electrical activity in cardiac muscle cells. An ECG is an EMG of the heart. (aka a voltmeter)
Define a Motor Unit
A motor neuron and all the muscle cells it innervates.
What happens during an EMG after the electrodes have been placed?
The Subject will contract the muscle. The presence, size and shape of the wave form (action potential) produced on the oscilloscope provides information about the ability of the muscle to respond.
Why is the test performed?
EMG is most often used when people have symptoms of weakness and examination shows impaired muscle strength. It can be used to differentiate primary muscle conditions from muscle weakness caused by neurologic disorders.
Why my it be needed for a kinesiologist?
For use in kinesiology studies to detect relative muscle activity during functional or sport activities (research).
What is Denervation?
Loss of a nerve. The nerve begins to degenerate. Diabetes can cause this.
What is Carpal Tunnel Syndrome?
Median nerve malfunctions and there is numbness and tingling of the palm of the hand.
What is Amyotrophic Lateral Scerosis?
ALS. Lou Gherig’s disease.
What is Duchenne Muscular Dystrophy?
Found in young children. Child displays weakness. Usually signaled by the child walking hand of the legs.
What is Polymyositis?
Many muscle inflammation. Disease/autoimmune disorder.
What is Myasthenia gravis?
Condition in which the neuromuscular junction is bad. The receptors are blocked by antibodies that the person is producing. Autoimmune disease.
What is an indwelling electrode?
Invasive needle. the needle is inserted through skin and into muscle to allow greater specificity in terms of muscle region, motor unit studies and allows access to deeper muscles.
