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Flashcards in 3. Muscle Fnx and Analysis Deck (26)
1

“Primary mover”
– Often considered as functional muscle group
• “elbow flexors”
– responsible for the initiation and execution of a
specific action at a joint

Agonists –

2

oppose or reverse the action of
the prime mover

• Antagonists –

3

assist the prime mover in its
actions

• Synergists –

4

Describe the concept of Recipricol Inhibition

Skeletal muscle functions usually includes pairs of muscles
• Depending on the muscle function one of the
pair muscles work as the agonist muscle and
the other the antagonistic muscle

5

For maximal muscle efficiency, speed and control
muscle pairs will:

– Increased tone in preparation for full activation
(getting the slack out)
– antagonist muscle prepares to slow down/ stop the
intended function
– The muscle pair need to coordinate their contractions to
avoid muscle injury

6

In neurologically intact patients, ________
reciprocal inhibition contributes to antagonist
suppression during movement

group Ia-mediated

7

When an individual axon is depolarized, an
_______l propagates down the nerve.

action potential

8

• Depolarization of all the fibers in a motor unit
creates an electrical potential called.

motor unit action potential (MUAP)

9

serves as the foundation for electromyography.

Analysis of the MUAPs (size, complexity, firing frequency) and assessment of baseline electrical signal at rest

10

How do we assess muscle function
clinically?

Manual muscle testing
• Motion analysis
• Electromyography

11

nerve compression, hereditary or acquired diseases, or
myopathy can be diagnosed via:

Electromyography and Nerve Conduction Studies

12

________ studies test motor, sensory, mixed
nerves

Nerve conduction

13

__________ tests skeletal muscle fibers
• Standard needle electromyography mostly tests type I
muscle fibers

Electromyography

14

MUAPs generated by contraction of an individual
muscle can be recorded by using

a surface or needle electrode

15

This information can be used to monitor that muscle’s activity during a certain action and to assess the integrity of the muscle and the nerves supplying it.

MUAPs from individual muscle contraction

16

Nerve conduction studies are a component of
electromyography. These studies assess

the integrity of the peripheral nervous system.

17

Number of muscles fibers innervated by a
single axon/motor neuron = innervation ratio

Description of motor unit

18

– Varies widely between muscles
– Low for fine motor
• Extraocular muscles
– High for gross motor
• Soleus

Motor unit

19

Size principle

During motor unit recruitement, larger MUs are recruited later

20

Lesion of the upper motor neuron in the central
nervous system occur in the Brain or Spinal cord. Cause what type of signs

Overactivity or “Positive Signs”
– Hyperreflexia
– Spasticity
• Underactivity or “Negative Signs”
– Weakness
• No inherent muscle atrophy

21

Overactivity or “Positive Signs”
– Hyperreflexia
– Spasticity
• Underactivity or “Negative Signs”
– Weakness
• No inherent muscle atrophy

UMN lesion

22

Velocity-dependent increase in tonic stretch reflex
(muscle tone)
• Hyperexcitability of the stretch reflex
• One component of the upper motor neuron
syndrome
• Decreased reciprocal inhibition

Spasticity

23

Intra-muscular injections can be used to reduce
focal muscle overactivity
• Affects both intrafusal and extrafusal muscle
• May affect nociceptor pathways via C and A
delta fibers and substance P as well

Botulininum Toxin

24

• Can be used to block salivary and sweat gland
• Used to treat numerous disorders: dystonia,
spasticity, ophthalmologic, GI/GU, dermatologic
and pain.

Botulininum Toxin

25

Mech of Botulininum Toxin

Gets internalized and cleaves SNAP 25

26

Needle EMG test

Type I fibers