Spinal Cord Flashcards
Name the vessels in clockwise manner
post. spinal arteries
ant. spinal artery
Aorta
segmental artery
radicular artery
Name the vessels in clockwise manner
basilar artery
ant. spinal artery
post. spinal artery
radicular arteries
artery of admakiewicz
vertebral artery
what do the post spinal arteries perfuse? How many are there?
post 1/3 of spinal cord
2 of them
what does the ant spinal artery perfuse? how many are there?
anter 2/3 of spinal cord
1 ant spinal artery
what supplies veritical blood supply to spinal cord?
ant and post spinal arteries
what supplies horizontal blood supply to spinal cord? How many are there?
6-8 radicular arteries
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
What supplies blood to ant and post spinal arteries in the cervical region?
vertebral arteries
what supplies blood to the ant and post spinal arteries in the thoracolumbar region?
radicular / lumbar arteries
what is the artery of adamkiewicz adn it’s significance?
largest and most important radicular artery. it perfuses ant spinal cord in thoracolumbar region.
what is another name for the artery of adamkiewicz?
great radicular artery
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
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.
another name for ant. spinal cord syndrome
beck’s syndrome
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
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
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
Name the spinal tracts in clockwise fasion starting with the right upper puruple tract
What is a ganglion
collection of cell bodies outside of CNS
gray matter is subdivided into what?
10 laminae
which laminae are sensory? dorsal or ventral?
1-6 (dorsal gray matter)
which laminae are motor? dorsal or ventral?
7-9 (ventral gray matter)
where is laminae 10?
surrounds central canal of spinal cord
what are the two sensory spinal tracts?
dorsal column - medial lemniscal system (DC-MLC)
antero-lateral system
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?
no
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?
C7
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?
no
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?
no
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
