Spinal nerves

Question 1

How many spinal nerves are there?

Answer 1

31 total 
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal

Question 2

What layers in the vertebral disc herniate?

Answer 2

nucleus pulposus (soft central disc) herniates through the annulus fibrosus (outer ring) usually occuring posterolaterally at L4-L5 or L5-S1

Question 3

In adults the spinal cord extends to the lower border of …. vertebrae

Answer 3

L1-L2

the subarachnoid space extends to lower border of S2 vertebra.

Question 4

Where is a lumbar puncture performed?

Answer 4

Performed between L3-L4 or L4-L5

“to keep the cord alive tap between three and five”

Question 5

Describe the layout of the dorsal column

Answer 5

Fasciculus gracilis (lower body) is medial

Fasciculus cuneatus (upper body) is lateral.

Question 6

What spinal levels will the intermediate horn be found within?

Answer 6

T1-L2/3

Question 7

What does the dorsal column translate?

Answer 7

Ascending Pressure, vibration, touch, proprioception

Question 8

What does the lateral spinothelamic tract translate?

Answer 8

Ascending Pain and temperature

Question 9

What does the anterior spinothelamic tract contain?

Answer 9

Ascending Crude touch and pressure.

Question 10

What does the lateral corticospinal tract translate?

Answer 10

This is a descending tract translating voluntary motor movement.

Question 11

What dos the anterior corticospinal tract translate?

Answer 11

Voluntary motor.

Question 12

Describe the cross of the dorsal column

Answer 12

Enters dorsal root ganglion and travels up ipsilaterally to the nucleus cuneatus where it crosses (medulla) and ascents conralaterally to medial lemniscus.

Question 13

Describe the cross of the spinothalamic tract

Answer 13

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.

Question 14

Describe the lateral corticospinal tract

Answer 14

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.

Question 15

Describe a lower motor neuron lesion

Answer 15

Everything is lowered (less muscle mass, less muscle tone, less reflexes, downgoing toes)

Fasciculations will be present.

Question 16

Describe an upper motor neuron lesion

Answer 16

Everything up
Tone, DTRs and upgoing toes.

Atrophy present.
Spastic paralysis and clasp knife spasticity

Question 17

When would you see a spastic paralysis?

Answer 17

UMN lesion

Question 18

When would you see a clasp knife spasticity?

Answer 18

UMN lesion

Question 19

How does polio virus lead to paralysis?

Answer 19

Destruction of the anterior horns.

Question 20

Tabes dorsalis

Answer 20

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.

Question 21

How does vitamin B12 effect the spinal cord?

Answer 21

Subacute combined degeneration of dorsal columns, lateral corticospinal tracts, and spinocerebellar tracts.

Leads to ataxic gait, parasthesia, impaired position and vibration sense.

Question 22

Brown Sequard syndrome

Answer 22

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.

Question 23

At what spinal level would a patient present with horners syndrome?

Answer 23

If a lesion occurs at T1 patient might present with it due to damage of the oculosympathetic pathway.