Spinal Cord Flashcards by Brandon Edmondson

Name the vessels in clockwise manner

post. spinal arteries
ant. spinal artery
Aorta
segmental artery
radicular artery

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Name the vessels in clockwise manner

basilar artery
ant. spinal artery
post. spinal artery
radicular arteries
artery of admakiewicz
vertebral artery

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what do the post spinal arteries perfuse? How many are there?

post 1/3 of spinal cord

2 of them

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what does the ant spinal artery perfuse? how many are there?

anter 2/3 of spinal cord

1 ant spinal artery

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what supplies veritical blood supply to spinal cord?

ant and post spinal arteries

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what supplies horizontal blood supply to spinal cord? How many are there?

6-8 radicular arteries

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where is the anterior spinal artery perfusion inconsistent? why is this important?

inconsistent flow in thoracolumbar region. this is important because it makes thoracolumbar region highly dependent on radicular flow

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What supplies blood to ant and post spinal arteries in the cervical region?

vertebral arteries

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what supplies blood to the ant and post spinal arteries in the thoracolumbar region?

radicular / lumbar arteries

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what is the artery of adamkiewicz adn it’s significance?

largest and most important radicular artery. it perfuses ant spinal cord in thoracolumbar region.

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what is another name for the artery of adamkiewicz?

great radicular artery

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where does the artery of admakiewicz commonly originate? Where else might it originate and how likely is this?

on left side between T11-T12

in 75% of population originates between T8 and T12

in 10% of population originates between L1-L2

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what creates “watershed” areas of the spinal cord? what does this mean?

ant and post spinal arteries run the entire length of the spinal cord, but not all levels receive horizontal blood supply. So these areas have a single blood supply and are vulernable to ischemia.

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another name for ant. spinal cord syndrome

beck’s syndrome

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what causes ant spinal cord syndrome

aortic clamp above level of artery of adamkiewicz can lead to ischmeia of lower portion of ant. spinal cord

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classis signs and symptoms of ant. spinal cord syndrome (becks syndrome)

flaccid paralysis of Lower Extremities
bowel and bladder dysfunction
loss of temp and pain sensation

preserved touch and proprioception

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what are the associated spinal pathways associated with each symptom of ant. spinal cord syndrome?

LE paralysis: cortical spinal tract
bowel/bladder dysfunction: autonomic fibers
loss of temp and pain: spinothalamic tract

preserved temp and proprioception: dorsal column

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Name the spinal tracts in clockwise fasion starting with the right upper puruple tract

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What is a ganglion

collection of cell bodies outside of CNS

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gray matter is subdivided into what?

10 laminae

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which laminae are sensory? dorsal or ventral?

1-6 (dorsal gray matter)

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which laminae are motor? dorsal or ventral?

7-9 (ventral gray matter)

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where is laminae 10?

surrounds central canal of spinal cord

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what are the two sensory spinal tracts?

dorsal column - medial lemniscal system (DC-MLC)

antero-lateral system

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what sensation does DC-MLC transmit?

fine touch proprioception vibration pressure (fine degree of intensity) two pint discrimination

how many neurons in the DC-MLC and antero-lateral systems?

both are 3 order neuron systems

where does DC-MLC cross to contralateral side?

it ascends ipsilateral side and crosses in the medulla

is DC-MLC fast or slow?

fast

what sensations does antero-lateral system transmit?

pain temp crude touch itch tickle sexual sensation

is antero-lateral system slow or fast?

slower than DC-MLC system

can antero-lateral system do 2 point discrimination?

where does antero-lateral system cross to contralateral side?

2nd order neurons cross to contralateral side then ascend via either lateral spinothalamic tract or ant. spinothalamic tract

lateral spinothalamic tract carries which sensations?

pain and temp

ant. spinothalamic tract carries which sensations?

crude touch and pressure

What is the most important motor pathway in the body?

Corticospinal tract

what is another name for corticospinal tract?

pyramidal tract

what does corticospinal tract transmit?

voluntary fine motor control to limbs coordination of posture

all other motor tracts besides corticospinal tract are?

extrapyramidal

what do lateral corticospinal tract fibers innervate? where do they cross to contralateral side?

limbs cross to contralateral side in the medulla

what do ventral corticospinal tract fibers innervate? where do they cross to contralateral side?

innervate axial muscles descent on ipsilateral side and cross to contralateral side in cervical or upper thoracic region

what are the two pathways within the corticospinal tract?

lateral and ventral corticospinal tracts

where are upper motor neurons within the corticospinal tract?

from cerebral cortex to ventral horn of spinal cord

how do upper motor neuron injuries present? Why?

contralateral spastic paralysis + hyperreflexia the inhibitory effects of upper motor neurons are blocked > overactivity manifest by paralysis and hypereflexia

what are two examples of upper motor neuron injuries

cerebral palsy and ALS

what does baniski reflex test?

integrity of corticospinal tract (-) test means tract is intact. toes curl down with firm pressure to underside of foot (+) test means corticospinal tract is damaged. upward extension of big toe with fanning of other toes when firm pressure applied to underside of foot.

how is baniski reflex affected with lower motor neuron injury?

baniski reflex is absent with lower motor neuron injuries

where are lower motor neurons found within the corticospinal tract?

ventral horn to NMJ

how do Lower motor neuron injuries present?

ipsilateral flaccid paralysis and impaired reflexes

acute spinal cord injuires most commonly occur from:

MVA, fall, assault, sports injury

what is most common site of SCI?

complete spinal cord injury damages what?

upper motor neurons

how does spinal cord injury present acutely vs after acute phase?

acutely: flaccid paralysis and loss of sensation below injury. (this includes loss of bowel and bladder function) after acute phase: spinal reflexes return > spasticity Neurogenic shock can also occur concurrently

neurogenic shock pathophys? symptoms? how is it differentiated from hypovolemic shock?

total sympathectomy below level of injury HoTN, bradycardia, hypothermia with pink warm extremities. Hypovolemic differences are tachycardia, cool clammy extremities

should you give fluids and pressors with neurogenic shock?

yes, they need both. be careful with fluids though, can cause fluid overload and pul edema especially after sympathectomy resolves

should you avoid Sux in acute SCI?

yes best to totally avoid. technically could maybe use the first 24hrs after injury, but fasciculations can make SCI worse so better to totally avoid.

M&M from SCI are mainly from blank and blank

ineffective alveolar ventilation and inability to clear pul secretions

what happens in chronic SCI and when does it develop? What does that put the patient at risk of developing?

develops after 1-3weeks body starts to heal itself but in a pathologic and disorganized way. spinal refelxes return below level of injury. These reflexes exist in an overactive state though because there is no inhibitory influence that would normally come from above. this put patient at risk for Autonomic hyperreflexia

what percent of patients with SCI above T6 develop AH?

85%

very rare to develop AH if SCI is below what level?

T10

common events that trigger AH

stimulation of hollow organs (bladder, bowel, uterus) bladder catheterization surgery (especially cystoscopy or colonoscopy) bowel movement cutaneous stimulation childbirth

what is the classic presentation of AH?

bradycardia with HTN and vasodilation above level of injury

blank is paramount when considering risk of AH

prevention is paramount

what kind of anesthesia is best for patient at risk of AH?

general or spinal

are epidurals okay for child birth with risk of AH?

okay but won't cover sacral nerve roots as well as a spinal would

how is AH HTN best treated?

remove stimulus deepening the anesthetic rapid acting vasodilators like clevidipine, nifedipine, or nitrates persistent HTN may require longer acting vasodilator

does adding lidocaine to cystoscope or foley catheter prevent AH?

is sux use okay in pt with or at risk of AH?

no, sux is Contraindicated

when can AH present during periop period that may be easily overlooked?

AH can present in PACU after anesthesia wears off, close monitoring is warrented.

What is amyotrophic lateral sclerosis (ALS)

progressive degeneration of both upper and lower motor neurons in corticospinal tract. astrocytic gliosis replace the affected motor neurons

s/s of upper motor invovlement in ALS

spasticity, hyperreflexia, loss of coordination

s/s of lower motor neuron involement in ALS

muscle weakness, fasiculations, atrophy

ALS often begins in the blank and spreads to blank

begins in the hands and spreads to other parts of body like tongue, pharynx, larynx, and chest

are occular muscles affected by ALS?

autonomic dysfucntion in ALS is evidenced by?

orthostatic HoTN and resting tachycardia

how is sensation affected by ALS?

sensation remains intact

what is the only medication shown to decrease mortality in ALS? Which class of medication is it?

riluzole nmda antagonist

what is the most common cause of death in ALS?

respiratory failure

what are the anesthetic mgmt considerations in ALS?

sux in contraindicated becasue of lethal hyper k from extrajunctional receptors associated with lower motor neuron injury ^ sensitivity to NDNMB bulbar m dysfunction puts patient at risk of pul aspiration chest weakness can lead to decreaed tidal volume and max minute ventilation. consider post op mechanical ventilation

What is Mass Reflex?

another name for autonomic hyperreflexia