Spinal Cord 1 Flashcards
pertinent antatomical areas on posterior/dorsal surface of SC?
- posterior median sulcus
- posterior intermediate sulci
- posterior lateral sulci
pertinent anatomical areas on anterior/ventral surface of SC?
- anterior median fissure
- anterior lateral sulci
what travels in the groove of the posterior intermediate sulcus?
posterior spinal artery
what travels in the groove of the anterior median fissure?
anterior spinal artery
what is significant of the lateral (both anterior and posterior) sulci?
that is where the rootlets arise from
order of meninges outermost to inner
- dura
- potential space for hematomas that must be created - otherwise dura and arachnoid are attached
- arachnoid
- subarachnoid space (CSF)
- pia - only one that goes into fissure
denticulate ligament
- connects pia and arachnoid matter
- prevents movement from side to side
funiculus
- group of fibers that don’t have same function/purpose
- ex: the 3 divisions of what matter:
- posterior, lateral and anterior funiculus
fasiculus
group of fibers w/ the same purpose
rexed laminae
- 10 divisions of grey matter
- each is a distinct region
fasiculus proprius
band around the grey matter that allows for communication b/w one level of SC to another - like internal circuitry
anterior white commissure
- one of the most important commissures in SC
- “cross bar” of grey matter
blood supply to the SC
- vertebral arteries –>
- anterior spinal a.
- posterior inferior cerebellar artery –>
- posterior spinal a.
- segmental arteries –>
- redicular arteries (help supplement)
what is the large redicular branch at the thoracic vertral level (even w/ renal arteries)
artery of Adamkiewicz
what side is the artery of Adamkiewicz
left
caution with the artery of Adamkiewicz:
- supplies spinal cord level that controls lower extremeties
- if getting renal arteriogram there’s a risk for flooding it w/ contrast
- if occluded, could get paralysis
- avoid during contrast studies
grey matter in the dorsal horn
- small cells
- related to sensory processing and projections
grey matter in the ventral horn
- large cells
- projections to muscles of the body
rexed laminae that make up the posterior grey column
I-VI
essentially the dorsal horn
rexed laminae that make up the lateral grey column
VII and X
rexed laminae that make up the anterior grey column
VIII and IX
lamina II
substantia gelatinosa of Rolando
laminae III and IV
nucleus proprius
what lamina is involved w/ referred pain
lamina V
lamina V
- neck of dorsal horn
- neuron involved in sensory afferent stimuli from cutaneous, muscle and join mechanical and visceral receptors
- viscerosomatic pain signal convergence often occurs here (pain referral)
which lamina deals w/ fast pain, i.e withdrawal from painful stimulus?
lamina VI
lateral grey column, lamina 7 and 10, deal mainly with what?
- visceral related
- 7: intermediolateral nucleus that contains preganglionic sympathetics and parasympathetics
- 10: around central canal; visceral afferent sensations (how fast HR, how dilated blood vessels are, etc)
anterior grey column, lamina 8 and 9, are what kind of neurons?
- big motor neurons
- going to skeletal muscle
noted structure within lamina 9
- onuf’s nucleus in sacral region
- related to pelvic function
how to distinguish axon from dendrites in a motor neuron
- all are multi-polar and large
- multiple dendrites and 1 axon
- the axon is clear, the dendrites are not
what is the effect on myelin and subsequently staining from a stroke?
- stroke kills cell bodies and axons
- loss of axon myelin = loss of stain
- this is how our brains were mapped back in the day
What are the main ascending tracts?
- Dorsal column (2)
- lateral spinothalamic tract
- spinocerebellar tracts
What are the main descending tracts?
MAIN: lateral corticospinal tract
- it’s modulators:
- rubrospinal tract
- vestibulospinal tract
- tectospinal tract
- reticulospinal tract
what are the 2 dorsal column divisions?
- fasciculus gracilis
- fasciculus cuneatus
fasciculus gracilis
carries sensation from lower extremities
fasciculus cuneatus
carries sensation from upper extremities
what is the cut off spinal level for the two dorsal column tracts?
- T6
- below T6 is only gracilis
- cuneatus is C5-T1
dorsal column (overall) transmits what senses?
- specific touch
- pressure
- 2 point discrimination
- vibration
- proprioception
where does the dorsal column synapse?
- in the medulla
- it enters the SC, ascends, THEN synapses, then decussates
where is the lateral spinothalamic tract located?
within the lateral funiculus, it’s a large tract
What does the lateral spinothalamic tract transmit?
- pain
- temp
- crude touch
fibers of the spinothalaic tract
C fibers
where does the spinothalamic tract synapse?
at the level it enters the SC, then crosses
spinocerebellar transmits what?
- muscle tension
- limb position
- sensory receptors from joint capsules
- integration of balance and movement
- not brought to level of conciousness
lateral corticospinal tract
- from cortex to spinal cord
- main descending pathway for volitional movement (control of fine movements)
- modulated by additional pathways
rubrospinal tract
- path
- what does it modulate
- from red nucleus in mesocephalon to the SC
- modulates flexion of upper extremities
What happens when the rubrospinal tract goes uncontrolled (for ex. from an injury)
flexion (decorticate) posturing
vestibulospinal tract
- think vestibulocochlear n.
- related to balance
- controls anti gravity muscles (extensors)
what happens when the vestibulospinal tract goes uncontrolled?
extension (decerebrate) posturing
tectospinal tract
- from an area involved in visual pathways
- allows you to turn head to a visual stimuli
reticulospinal tract
- where
- fxn
- located b/w all different nuclei in the brain stem
- inhibits or excites depending on the brainstem level
what are the 3 prominent divisions in terms of white/grey matter organization in the SC?
- cervical enlargement
- lumbar enlargement
- sacral section
cervical enlargement
high density of motor neurons going to upper extremities give large ventral horn
lumbar enlargement
high density of motor neurons going to lower extremities gives large ventral horn
sacral SC region
- little white matter
- lg amount of grey matter (going to UG and pelvic diaphragm)
Describe a cross section of the low cervical SC
- can distinguish gracilis and cuneatus (tells you it’s above T6)
- lg. ventral horn (upper extremities)
- lg. white matter area
Describe a cross section of the low thoracic SC
- lack of cuneatus
- only gracilis
- tiny dorsal horn
- small ventral horn
what significant structure is found in a section of the thoracic SC?
clarke’s column
clarke’s column
related to spinocerebellar tract - relay for proprioception
Describe a cross section of the low lumbar SC
- small amount of white matter
- large ventral horn
- big dorsal horn
Describe a cross section of the mid sacral SC
- very little white matter
- relatively great amount of grey matter
- big dorsal and ventral horn
significant structure found in the sacral SC?
lateral horn from the interomediolateral cell column
what does the interomediolateral cell column contain?
ANS neurons: S2, S3, S4 parasympathetics
