Disorders of Spine Flashcards
What way are the sensory fibres arranged within the spinal cord?
Fibres carrying cervical information are closest to the dorsal horn
then thoracic, then lumbar then sacral around around edge of the cord
What way are the motor fibres arranged within the spinal cord?
Descending fibres carrying information to cervical area closest to anterior horn
then thoracic, lumbar then sacral
sacral found most medially
What are the two sensory systems?
dorsal column system
spinothalamic tract
How many neurones are needed in each sensory systems?
- always use three neurones
- the first coming from dorsal root ganglion
- last neurone always in thalamus (contralateral side of dorsal)
Describe the Dorsal column tract?
- neurone enters through dorsal root ganglion
- travels immediately up dorsal column
- reaches medulla where second neurone synapses
- second neurone crosses over and travels to thalamus
- third = thalamus > cortex
What type of information is carried by the Dorsal column tract?
Fine touch and proprioception
Describe the difference in spinothalamic tract compared to DCT?
- first neurone synapses with second neurone in the dorsal horn of spinal cord
- second neurone crosses immediately
- synapses with third neurone in thalamus which travels to cortex
What type of information is carried by the spinothalamic tract?
Pain and temperature
How many neurones are involved in each motor pathway?
Two
Describe the motor pathway?
- first neurone starts in pyramidal cells in cortex
- travels through internal capsule and brainstem
- at end of brainstem crosses over
- enters spinal cord where it will synapse with second neurone in ventral horn
What are the two descending motor pathways?
Lateral corticospinal tract
rubrospinal tract
What information does rubrospinal tract carry?
- motor information to the toe
- works by suppressing the second neurone (which is why toe curls if damage to rubrospinal)
What other words can be used to describe the upper and lower motor neurone lesion?
Upper = central or first
Lower = peripheral or second
What motor changes will occur with a UMN or LMN lesion?
reduced/ missing power
What muscular tone changes will occur with a LMN and UMN lesion?
LMN - Decreased muscular tone
UMN - Increased (spastic)
How does muscular tone change in Parkinsons’s?
get rigid muscular tone
What does spastic tone mean?
- if continuously contract muscle will eventually collapse muscle so for example drop arm
What commonly occurs to deep tendon reflexes in UMN or LMN lesions?
UMN - Exaggerated, increased reflexogenic zone and polyclonal answers
LMN - Weak/missing
What is polyclonal answer?
get multiple responses from one stimulation of reflex
What is increased reflexogenic zone?
if you stimulate area near reflex will still get a response
What pathological reflexes (shouldn’t be present) are present in UMN lesion?
Hoffman - flick finger middle finger will result in grasping motion of other fingers (Pos response)
Babinski - move finger up from bottom of sole of foot to top and toe will curl upward instead of down
What pathological reflexes are present in LMN lesion?
none will display neither hoffman or babinski
What are the spine enlargements?
1) cervical enlargement (C5-C8) - second neurone (where first neurone is travelling to reach) for the arms
2) Lumbar enlargement - second neurone for legs
What are the possible causes of spinal injury?
- trauma
- herniated disc
- tumour
- infection
What neurones are affected by high cervical (C1-C4) injury?
quadriplegia + sensation loss depending on which spinal cord segment affected e.g. C4 innervates shoulders and lower neck
first neurone affected which means second neurone will also not receive signal
What problems will a high cervical injury cause?
1) quadriplegia
2) sensation loss in dermatome of affected vertebrae
3) bladder retention / constipation
4) breathing problems
Why is there breathing problems with high cervical lesions?
2nd neurone in thoracic region is for intercostal muscles
signal going to the 2nd neurone is stopped at cervical region so unable to breath with intercostal muscles (can still breath with diaphragm but even diaphragm partially impaired)
What neurones will be injured by a low Cervical injury (C5-T1)?
In lower limbs first neurone affected not second neurone
In upper limbs both first and second neurones damaged
What problems occur with low cervical injury?
- weakness in upper limbs (flaccid not spastic)
- Decreased tone upper limbs
- lower limbs weakness (spastic)
- bladder and bowel impairment
- lose sensation in dermatome of spinal cord segment affected
What is the difference in problems occurring in high and low cervical injury?
- breathing problems only in high cervical
- low cervical will cause flaccid weakness in upper limbs
What problems occur with thoracic (T2-T12) injury?
- breathing problems (only breathe with diaphragm not chest)
- lower limb paralysis (spastic)
- bowel and bladder impairment
When is paralysis spastic and when is it flaccid?
spastic when second neurone intact (2nd neurone still fires increasing tone)
flaccid when both first and second neurone affected
What problems can occur in lumbar enlargement injuries (L1-S1)?
- lower paraplegia (flaccid)
- bowel and bladder impaired
- lose sensation in corresponding dermatomes
What problems can occur in injuries of Cauda Equina and S2?
- upper limbs intact
- can have flaccid weakness of lower limbs
- impairment of bowel and bladder (peripheral)
- sensation lose in corresponding dermatome (saddle region)
- loss of anal tone
When will there be peripheral impairment of bladder and bowel and when will there be central?
Peripheral only in S2 and cauda equina injury (leaking of bladder/bowel)
rest of spine will result in central
What is the cauda equina?
axons of second neurone
What is Brown Sequard syndrome?
- injury involves only one side of cord (hemicord lesion)
- half of body will then be affected
- symptoms depend on location of lesion
In brown sequard syndrome which symptoms will be ipsilateral and contralateral?
ipsilateral (side of lesion) - paralysis - deep sensation - proprioception Contralateral (opposite) - pain - temperature
Which spinal cord vertebrae correspond with which spinal cord segments?
(most are slightly offset so C8 segment is not at C8 vert)
C4-C6 = +1 (corresponding seg is one higher)
C7-T5 = +2
T6-T11 = +3
T12 = +4
L1 = conus medullaris
L2-S2 = Cauda equina
