Other Motor Pathways Flashcards
where does the rubrospinal tract start
red bodies of midbrain
where in the spinal cord does the rubrospinal tract synapse
lateral aspect of the ventral horn
where does the vestibulospinal tract start
vestibular nuclei in medulla
where does reticulospinal tract start
reticular formation in medulla
function of rubrospinal tract
involuntarily flexes UE and extends LE when lat corticospinal tract doesnt work
function of medial vestibulospinal tract
automatic positioning of the head with changes in posture with respect to gravity
function of lateral vestibulospinal tract
automatic changes in body required to keep balance
function of reticulospinal tract
automatic changes in posture with gait movements
decorticate posturing
flexion of UE and ext of LE
which pathway facilitates decorticate posturing
rubrospinal tract
what are the three voluntary motor pathways
lateral corticospinal tract
anterior corticospinal tract
corticobulbar tract
is MS a disorder of the UMN or LMN
UMN
is Lou Gehrig’s disease a disorder of the UMN or LMN
LMN
atrophy
shrinkage of muscle due to loss of LMN innervation
fasciculation
involuntary muscle contractions (twitches) that are visible, but not strong enough to move a joint
what causes fasciculations
damage to LMN
muscle membrane becomes irritable and action potentials occur at random
damage to LMN leads to (increase/decrease) in muscle stretch reflex
decrease
damage to UMN leads to (increase/decrease) in muscle stretch reflex
increased
why is muscle stretch reflex increased with damage to UMN
less UMN inhibition to LMN, therefore LMN closer to threashold
positive Babinski’s sign
toes fan out when bottom of foot is scratched
what does a positive Babinski’s sign indicate
UMN problem
what is tone
resistance felt by an examiner when she moves a patient’s limb through its ROM
how is tone determined in body
- balance between excitatory and inhibitory stim to LMN
- state of muscle spindle
how is tone measured
examiner initiates an action potential in Ia neuron by passively stretching muscle
-tone is the resistance felt by examiner
tone is (increased/decreased) with UMN problems
increased
tone is (increased/decreased) in LMN problems
decreased
spasticity
weakness with increased tone and increased muscle stretch reflexe
positive Babinski’s sign
spasticity is a result of (UMN/LMN) injury
UMN
amyotropic lateral sclerosis
destruction of LMN & UMN
