Flashcards in Muscle Function: Analysis and Demonstration Deck (24)
Primary mover; responsible for the initiation and execution of a specific action at a joint
Opposes or reverses the action of the prime mover
Assists the prime mover in its actions
Skeletal muscles function in pairs; one of the muscles works as the agonist muscle and the other the antagonist
Analysis of motor unit action potentials (MUAP) and assessment of baseline electrical signal at rest
Recorded using a surface or needle electrode
Can be used to monitor a muscle's activity during a certain action and to assess integrity of the muscle and nerves supplying it
What is a motor unit?
All the muscle fibers innervated by one nerve
The number of muscle fibers innervated by a single axon/motor neuron
-Varies widely between muscle
-Low for fine motor (extra ocular muscles)
-High for gross motor (soles)
What are some of the different kinds of muscle action potentials?
Motor unit action potential
Sensory nerve action potential
Compound muscle action potential
What is the size principle?
Motor units are recruited from smallest to largest size.
How can electromyography be used to diagnose disease?
Tests skeletal muscle fibers
Standard needle electromyography mostly tests type I muscle fibers
How can Nerve conduction studies be used to diagnose disease?
Tests motor, sensory and mixed nerves
What are the three types of contraction?
Limb is shortening
Limb is lengthening
No movement but still contracting
When you walk are there more eccentric or concentric contractions?
Name some agonists of wrist flexion.
Flexor carpi radialis
Flexor carpi ulnaris
Flexor digit profundus
Flexor digit sublimis
Name some antagonists of wrist flexion.
Extensor carpi radialis longus and brevis
Name some agonists of hip flexion.
Tensor fasciae latae
Name some antagonists of hip flexion.
What is upper motor neuron syndrome?
Lesion of upper motor neuron in the CNS
Overactivity -- hyperreflexia, spasticity
Underactivity -- weakness
No inherent muscle atrophy
What is spasticity?
Velocity-dependent increase in tonic stretch reflex (muscle tone)
What can be used to reduce focal muscle overactivity?
Effects intrafusal and extrafusal muscle
May affect nociceptor pathways via C and A delta fibers and substance P
Can also be used to block salivary and sweat gland