First aid neuroanatomy and physio part 2 Flashcards
Which nerves exit above the corresponding vertebra?
C1-C7
Which nerves exit below the corresponding vertebra?
Everyone below C7
Vertebral disk herniation
- nucleus pulposus (soft central disk) herniates though the annulus fibrosis (outer ring)
- usually occurs posterolaterally at L4-L5 or L5-S1
Where does the spinal chord end?
L1-L2
Where does the subarachnoid space extend to?
S2
Where do we do a lumbar puncture?
L3-L4 or L4-L5.
To keep the chord alive keep the needle between L3 L5
Spinal chord associated tracts orientation
Legs are lateral in lateral corticospinal and spinothalamic (anterior lateral) tracts
Dorsal columns are organized like you, hands at sides so arms on the outside and legs on the inside
Upper motor neuron signs
- weakness
- increased reflexes
- increased tone
- postive babinski
- positive spastic paralysis
- clasp knife spasticity
lower motor neuron signs
weakenss atrophy fasiculations decreased reflexes decreased tone increased falccid paralysis
Dorsal column tract
Ascending:
pressure, vibration, fine touch and proprioception
Sensory nerve ending –> cell body in doral root ganglion –> enter spinal cord asceds ipsilaterally in dorsal columns.
- synapses at ipsilateral nucleus cuneatus or gracilis in the medulla
- decussates in medulla and ascedns contralateraly in the medial reminisces
- synapses at VPL
- goes to sensory cortex
LAterial Spintholamic tract (anteriolateral)
pain and temp
sesory nerve fibers (Adelta and C) cell body in dorsal root ganglion –> enters spinal chord
-synapses on ipsilater reay matter
-decussates at the anterior white commisure
-ascends contralaterally
-synapses on VPL
-then heads to the sensory cortex
Lateral corticospinal tract
descending voluntary movement of contralateral limbs
so UMN cell body in the primary cortex –> descends ipsilateraly though the internal capsule, most fibers decussate at caudal medulla (pyramid decussation)–> descends contralateraly till cell body in anterior horn–LMN leaves spinal cord and synapses at the NMJ
Spinal cord lesion: Poliomyelitis and spinal muscular atrophy (wednig hiffmann disease)
- LMN lesion
- destruction of anterior horns!
- flaccid paralysis
Spinal cord lesion: MS
- due to demyelnation
- mostly white matter of cervical region in the dorsal columns, but random and asymmetric lesions
- scanning speech, intention tremor and nystagmus
Spinal cord lesion: AML
UMN and LMN
- no sensory deficts
- can be caused by a defect in superoxide dismutase 1
- anterior horns and cortiocalateral spinal tracts
presents with
fasiculations with eventual atrphy and weakenss of hands
treat: riluzole which decreased glutamate release
Spinal cord lesion: ASA occlusion
- spares dorsal columns and lissauer tract
- everything else
- note the upper ASA territory is watershed area as the artery of adamkiewicz supplies ASA below T8
Spinal cord lesion: Tabes dorsales
- tertiary syphillis
- degeneration of dorsal columns
- imparined sensation and proprioception and progressive sensory ataxia–> inability to sense or feel the legs–> poor coordination
assoc with charcot joins, shooting pain, argyll robertson pupuls
-postive romberg
What is Argyll Robertson Pupils?
- tertiary syphillis
- small bilateral pupils that further constrict to accommodation and convergence but NOT TO LIGHT
Syringomyelia
- syrinx expands and damges anterior white commisure of pniothalamic tract–> bilateral loss of pain and temperature sensation usually C8-T1
- assoc with Chiari I
- can expand and effect other tracts like the anterior horns
Vitamin B12 or Vitamin E deficiency
-subacute combine degerenation-demyelination of dorsal column and lateral corticospinal tracts and spinocerebellar tracts; ataxic gait, parenthesis, impaired postion and vibration sense
Poliomyelitis
- polio virus
- RNA virus
- Fecal oral
- replicates in the oropharynx and small intestine before spreading via bloodsteam to the CNS
- anterior horn destruction
- CSF increased wbc and slight increase in protein
werdnig hoffman disease spinal muscular atrophy
congenital degredation of anterior horns
- LMN
- floppy baby
- tongue fasiculations
- Autosomal recessive
- death by 7 months
Friedreich ataxia
Autosomal recessive trinucelotide repease disorder (GAA)
- chromosome 9 in the gene that encodes frataxin
- leads to impairment in mitochondrial functioning
- degeneration of multiple spinal cord tracts
- muscle weakness and loss of DTRs, vibratory sense, proprioception
- staggering ait, frequent falling, nystagmus, dysarthia, pes cause, hammer toes, hypertrophic cardiomyopathy
- kyphoscoliosis
Brown sequard syndrome
Hemisection!! of spinal chord
- ipsilateral UMP signs below the level of the lesion due to corticopisnal tract damage
- ipsilateral loss of tactile, virbration and proprioception 1-2 levels below the lesion due to damage of dorsal column
- contralateral pain and temperature loss below the level of the lesion due to damage of the spinothalamic tract
- ipsilateral loss of alllll sensation at the level of the lesion (pain and proprio have not crossed the commisue yet at the entrance level)
- ipsilateral LMN signs due to destruction of anteroir horn at the level
note if the lesion is above T1 –> horners
Horner syndrome
- ptosis
- anhidrosis (absence of sweating and flushing of affected side of face)
- miosis (pupil constriction)
lesion of spinal chord above T1 like:
pancoast tumor, brown seqaurd, late stage syringomyelia)
Why?
Oculosympathetic pathway:
hypothalamys to the intermediolateral column of the spinal chord, then to the superio cervical sympathetic ganglion then back upto the pupil, smooth muscle of eye lids and sweat glands of the forehead and face.
C2
posterior half of the skull (cap)
C3
high turtle neck shirt
C4
low collar shirt
T4
nipple
T7
xiphoid process
