Muscle Function: Analysis and Clinical Demonstration Flashcards
(42 cards)
What is manual muscle testing?
- testing the structural unit
- tests groups of muscles, not an isolated muscle
- agonist, antagonists, synergists
- check planes of movemnet and types of contraction
What are electromyography (EMG) and Nerve Conduction Studies
testing the functional unit
- detailed evaluation of muscle and nerve function/ innervation
WHat is an agonist?
a primary mover
- responible for the initiaon and execution of a specific action at a joint
- often considered as a function muscle group
what are muscle antagonists?
What are synergists?
antagonists-oppose or reverse the action of the primary mover
synergist-assist the prime mover in its actions
How do agonists and antagonist work together to facilitate joint movement?
Reciprocal Inhibition
- ensures smooth movement of a joint skeletal muscles function in pairs for maximal muscle efficiency speed and control and prevent injury
- agonist: increases tone for full activation
- antagonist: prepares to slow down/stop the intended function
Describe how reciprocoal inhibition works in a neurologically in tact person.
How about a neurologically compromised patient
- Ia afferent enters spinal cord, synapses on the alpha motor neuron and causes the agonist to contract
- at the saem time the other branch of the Ia afferent sunapses on the Ia inhibitory interneuron which synapse on the alpha motote neuron of the anatagonist, preventing the contraction of the antagonizing muscle group
- Neurologically compromised
- lack of reciprocal inhibition (lack of descending inhibition)
- causes spascitity
What are the 3 planes of movement?
- Frontal/Coronal
- divide body into anterior and posterior
- abduction, adduction
- divide body into anterior and posterior
- Sagittal
- divide body into right and left
- felxion/extension
- divide body into right and left
- Transverse/horizontal
- divide body into top/bottom
- internal and external rotation
- divide body into top/bottom
what are the agonist for shoulder abduction?
deltoid and surpaspinatus
antagonists for shoulder abduction? aka the adductors
latissimus dorsi
pectoralis major
teres major
what is a winged scapula
- spinal accessory nerve for trapezius injury. increased winging with abduction
- or if more prominent winging with flexion=long thoracic nerve/serratus anterior injury
How do you test for muscle integrity?
check plaes of movement
primary mover, antagonists, planes of movement
what are som eabnormalities that could be present when testing plnes of movement for dorsiflexion of ankle?
inversion or eversion could be prominent
different plane of movement coudl be utilized
they could be accomodating with other muscle groups!
Wat are the 3 types of contraction?
- Isotonic
- concentric
- muscle shortens
- eccentric
- muscle elongates
- concentric
- Isometric
- muscle length remains the same
wht type of contraction is capable of producing the greatest amount of force?
eccentric contractions
- require less metabolic energy
- with maximal contraction they can generate much higher tension levels when compared to concentric contractions
- up to 50% higher!
- important concept in rehab of tedinopathies
What kind of exercise should a 75 yo man who just had an MI avoid?
isometric! (planks) bc it can increase blood pressure
What kind of exercise would you want to do on a 20 yo with achilles tendinopathy?
- eccentric! they generate the most force. this stimulates collagen growth factors which will repair the damaged achilles tendon!
What is the purpose of electromopathy?
- certain disease processes such as nerve compression, hereditary or acquired diseases or myopathy will result in alteration of the normal recorded electrical signals and recruitment patterns
- these diseases can be diagnosed with EMG and NErve conduction studies
- EMG tests skeletal muscle fibers (type 1, slow twitch, muscle fibers)
- nerve conduction tests motor, sensory, mixed nerves (standard studies are evaluating Ia large myelinated nerve fibers)
WHat do EMGs test?
What do Nerve conduction studies test?
- EMG: skeletal muscle . fibers (mostly type 1, slow twitch, muscle fiber)
- nerve conduciton studies: motor, sensory, mixed nerves (standard studies are evaluating Ia large myelinated nerve fibers)
what is the functional element of the neuromuscular system?
A motor unit! (LMN)
anterior horn cell (LMN)
axon
NMJ
Muscle fibers
WHat is innervation ratio? what is it ssignificance?
the number of msucel fibers that belong to a ingle axon (innervated by a single axon)- important bc you dont need a ton of innervation for fine movemnts!
- varies widely between muscles
- low for fine motor: extraocular
- high for gross motor: soleus to stand on your toes
**high innervation ratio=greater force generated by that motor unit**
all muscle fibers innervated by one motor unit are ________
of the same muscl fiber type
When an individual axon is depolarized an action potential propagates down the nerve. what happens with depolarization of all fibers in a motor unit?
an electrical potential called a motor unit action potential (MUAP)
analysis of the MUAP (size complexity firing frequency) and assesment of baseline electrical signal at rest served as the foundation for electromyography
How do we record MUAPs of an individual muscle?
EMG- usuing a surface needle electrode
this infor can be used to monitor that muscle’s activity during a certain action and to asses the integrity of the muscle ans the nerves supplying it
What id Henneman size principle?
- the first motor unit is recruited at 5 Hz but to generate more force the firing rate and recruitment of more motor units must be increased
- patterns of recruitment indicate neuropathic (reduced) vs. myopathic (early) conditions
