Spinal nerves Flashcards
How many spinal nerves are there?
31 total 8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal
What layers in the vertebral disc herniate?
nucleus pulposus (soft central disc) herniates through the annulus fibrosus (outer ring) usually occuring posterolaterally at L4-L5 or L5-S1
In adults the spinal cord extends to the lower border of …. vertebrae
L1-L2
the subarachnoid space extends to lower border of S2 vertebra.
Where is a lumbar puncture performed?
Performed between L3-L4 or L4-L5
“to keep the cord alive tap between three and five”
Describe the layout of the dorsal column
Fasciculus gracilis (lower body) is medial
Fasciculus cuneatus (upper body) is lateral.
What spinal levels will the intermediate horn be found within?
T1-L2/3
What does the dorsal column translate?
Ascending Pressure, vibration, touch, proprioception
What does the lateral spinothelamic tract translate?
Ascending Pain and temperature
What does the anterior spinothelamic tract contain?
Ascending Crude touch and pressure.
What does the lateral corticospinal tract translate?
This is a descending tract translating voluntary motor movement.
What dos the anterior corticospinal tract translate?
Voluntary motor.
Describe the cross of the dorsal column
Enters dorsal root ganglion and travels up ipsilaterally to the nucleus cuneatus where it crosses (medulla) and ascents conralaterally to medial lemniscus.
Describe the cross of the spinothalamic tract
Alpha delta and C pain fibers enters spinal cord and crosses in the ipsilateral gray matter (spinal cord)
Dessucates at the anterior white commissure ascends contralaterally.
Describe the lateral corticospinal tract
This is a descending tract.
UMN Descends ipsilaterally and crosses in the anterior horn. the LMN then leaves the spinal cord and travels to the NMJ.
Describe a lower motor neuron lesion
Everything is lowered (less muscle mass, less muscle tone, less reflexes, downgoing toes)
Fasciculations will be present.
Describe an upper motor neuron lesion
Everything up
Tone, DTRs and upgoing toes.
Atrophy present.
Spastic paralysis and clasp knife spasticity
When would you see a spastic paralysis?
UMN lesion
When would you see a clasp knife spasticity?
UMN lesion
How does polio virus lead to paralysis?
Destruction of the anterior horns.
Tabes dorsalis
Caused by tertiary syphilis
Degeneration of the dorsal columns and roots.
Impaired sensation and proprioception with progressive sensory ataxia.
(cannot feel the legs) associated with charcot joints and prostitutes pupils.
How does vitamin B12 effect the spinal cord?
Subacute combined degeneration of dorsal columns, lateral corticospinal tracts, and spinocerebellar tracts.
Leads to ataxic gait, parasthesia, impaired position and vibration sense.
Brown Sequard syndrome
Hemisection of the spinal cord resulting in:
Ipsilateral UMN signs below the level of the lesion.
Ipsilateral loss of tactile, vibration, proprioception sense below the lesion.
Contralateral pain and temp loss.
At what spinal level would a patient present with horners syndrome?
If a lesion occurs at T1 patient might present with it due to damage of the oculosympathetic pathway.
