Disorders of the Spine Flashcards
inner fibres and outer fibres of the white matter of the spinal cord in each section are responsible for functioning where ( motor and sensory )
inner : Cervical functioning
middle : thoracic then lumber
outer : sacral
What are the 2 subsystems of the sensory pathway
1- Dorsal column system
2- spinothalamic tract
Where are the 3 neurons systems in the dorsal column system and spinothalamic tracts ( Explain pathways in detail )
Neurons transfer info from peripheral organ ( skin ) to cortex
1st neuron - located in dorsal root ganglion , travels up SC
2nd-
Dorsal system : 1st neurone reaches second neurone in medulla and 2nd neurone projects axon to cross over contralaterally then go towards thalamus
Spinothalamic : axon of 1st neuron enter posterior horn of grey matter where second neurone is , will crossover immediately in SC then travel to thalamus
3rd- located in thalamus contralateraly to dorsal root ganglion and axon goes to Cortex
What is the dorsal column system responsible for
Fine touch and proprioception of body
What is spinothalamic tract responsible for
pain and temperature sensation
What the divergence between the dorsal column system and spinothalamic tract
Dorsal column : 2nd neuron is in the medulla and cross over happens there
Spinothalamic : 2nd neuron is in the posterior horn of grey matter and cross over will happen there in the SC
What if a something is inactivating half of the SC ( hemisection of cord ) , on presentation what will be missing on the side of the lesion and what will be missing on the opposite Side
Side of lesion : missing fine touch and proprioception because dorsal column system doesn’t cross over till medulla
Opposite side : missing pain and temperature because spinothalamic tract in that lesion is responsible for other side
What are the 2 motor pathway systems
1- Pyramidal : starting from cortex and crosses over at the pyramidal decussation before the spinal cord
2- extrapyramidal : start from midbrain and crosses over at the midbrain
What is the function of the rubrospinal tract ? what happens if it is missing ?
To suppress the second motor neuron it meets in the spinal cord.
If missing then suppressing role won’t be there and spinal tone will be increased
Why does UMN lesion give you increased muscular tone
If there is a lesion to the rubrospinal tract that stops it’s suppressing role and thus muscle tone goes up
What is the difference between motor function in UMN lesion or LMN lesion
UMN : reduced power / missing power
LMN : reduced power/ missing power
What is another name for UMN
Central MN and first MN
What is another name for LMN
Peripheral MN , second MN
What is the difference between abnormalities in deep tendon reflexes in UMN lesion or LMN lesion
UMN : exaggerated , brisk , increased reflexogenic zone , polyclonal answers
LMN : weak / missing
What is the difference between pathological reflexes in UMN lesion or LMN lesion
UMN : Hoffman and Babinski present
LMN : missing
What is the difference between muscular tone in UMN lesion or LMN lesion
UMN : increased/spastic
LMN : decreased/missing
What creates the muscular tone and what suppresses it
Created by : 2 motor neurone / LMN
Suppressed by : rubrospinal tract / UMN / 1st neurone
What is typical for Parkinson’s increased muscle tone
Rigidity