Neuroanatomy Lecture 4: Spinal Cord Flashcards
what does the Corticospinal/ pyramidal tract carry
voluntary motor
what does the Posterior/ dorsal column carry
main sensory:
touch, tactile localisation, vibration sense, proprioception
what does the Lateral spinothalamic tract carry
pain and temp
what part of internal capsule does corticospinal tract go through
posterior limb
what type of fibres do cranial nerves leave through
early through corticobulbar fibres
where do corticospinal fibres cross
decussation of pyramids
where do motor fibres leave if going to:
neck
upper limb
intercostal muscles
neck = cervical level to cervical plexus
upper limb = ventral horns of C3-T1 brachial plexus
intercostal = T1-L2
where do LMN of corticospinal tract sit
ventral horn
where do the first order neurons become second (i.e cross over) in POSTERIOR/ DORSAL COLUMN
medulla
what is the POSTERIOR/ DORSAL COLUMN called after it cross with 2nd order neuron
medial lemniscus
journery of POSTERIOR/ DORSAL COLUMN fibres x4
1st order neuron travels to medulla and synapses with 2nd after crossing
now is medial lemniscus synapses in thalamus
to become third order
3rd order travels to internal capsule then post central gyrus
whats the blue part called
what travels down in
crus cerebrii
cerebrospinal - motor
whats travels down the red bit
all sensory- spinithalmic and dorsal collumn
journey of spinothalmic tract
1st order synapses as soon as it enters spine
2nd order travels up to thalamus
3rd order from thalamus to internal capsule
internal capsule to post central gyrus
what tract is this
how can you tell
corticospinal tract
starts in multiple areas of brain
crosses in medulla
leaves through ventral horn
what tract is this
how can you tell
posterior/dorsal collumn
crosses at pyramids
leaves through dorsal collumn
what tract is this
how can you tell
lateral spinothalamic
crosses in spinal cord
stretch reflex pathway x6
- tendon gets stretched
- muscle fibres stimulated
- sensory neuron activated
- MONOsynaptic reflex arc
- muscle contracts
also:
4b. POLYsynaptic reflex arc inhibits antagonist muscle
flexor reflex pathway
- pain
- sensory neuron activated
- POLYsynaptic reflex arc
- flex and withdraw
4b. Crossed extensor response to other limb (only in legs)
what type of neurons do reflexes use
LMN
what do UMN neuron problems do to reflexes
exaggerate them
what type of neurons control muscle tone
LMN
how do UMN/LMN effect muscle tone
UMN increases tone
LMN decreases tone
what does a L UMN lesion at internal capsule cause x3
*R sided paralysis
*Hyper-reflexia
*Increased tone
what does L UMN lesion at upper cervical spinal cord cause
*L sided paralysis- crossed over by this point
*Hyper-reflexia
*Increased tone
what does a L LMN lesion cause
*L sided paralysis
*Absent reflexes
*Flaccid
when are symptoms contralateral
when lesion is above deccusation of pyramids
when are symptoms ipsilateral
when lesion is below deccusation of pyramids
what does brown-sequard syndrome effect x4
exact half of spinal chord- 1 ventral and dorsal horn of same side
so same side of lesion will loose motor and sensory
same side increased reflexes
with other side loss of pain and temp
symptoms of Brown-Sequard Syndrome of left side of C3
Left sided paralysis
Left sided loss of touch, vibration sense
Right sided loss of temperature and pain
Reflexes on left side exaggerated
what does damage to an UMN cause X5
hyperreflexia
hypertonia
spasticity
Positive Babinski sign
CLONUS
