Spinal Cord anatomy and conditions Flashcards
Motor Conditions
Amyotrophic lateral sclerosis
Poliomyelitis
ALS area affected?
affects both upper (corticospinal tracts) and lower motor neurons
results in a combination of upper and lower motor neuron signs
Do UMN innervate ipsilateral or contralateral muscles
contralateral
Do LMN innervate ipsilateral or contralateral muscles
ipsilateral
Why do lower motor neurone signs occur the way they do?
loss of trophic effect on muscles
What are the LMN signs?
weakness
wasting
fasciculation
hypotonia
hyporeflexia
Why do upper motor neurone signs occur the way they do
Occur due to hyper excitability of inputs to anterior horn cells
What are the UMN signs
weakness - extensor weakness in upper limbs and flexor weakness in Lower limbs
no wasting
hypertonia, spasticity
hyperreflexia
loss of fine motor movement
pronator drift
extensor plantar response
clonus
What are the ddx for LMN lesions
ventral horn pathology - MND, post-polio
peripheral nerve pathology
NMJ pathology
Muscular pathology
What are the dx for UMN lesions
Vascular: stroke
Inflammatory: MS, MND
Neoplastic: Tumour
Degenerative: Parkinson’s
Infective: Post-meningitis
Extra: drugs
What are the descending tracts?
MOTOR:
Dorsal and ventral CORTICOSPINAL TRACTS
are the corticospinal tracts contralateral or ipsilateral?
ipsilateral as they decussate in the brainstem
What is the function of the corticospinal tract?
transmit motor axons from the motor cerebral cortex to the spinal spinal cord
What are the ascending tracts?
SENSORY:
dorsal columns
spinothalamic tract (lateral and ventral)
What is the function of the dorsal columns?
Transmit deep touch, joint position and vibration to the parietal cortex
Are the dorsal columns ipsilateral or contralateral?
ipsilateral - decussate in the brainstem
What is the function of the spinothalamic tract?
transmits pain, temperature and light touch to the thalamus
Is the spinothalamic tract ipsilateral or contralateral?
contralateral
decussates at the spinal level
What clinical syndrome would arise from a cord transection at C3?
Neurogenic shock
Respiratory insufficiency
Quadriplegia
Anaesthesia below the affected level
Loss of bladder/bowel sphincter tone
Sexual dysfunction
Horner’s syndrome
What clinical syndrome would arise from a cord transection at T10?
Paraplegia
Anaesthesia below the affected level
Loss of rectal / bladder sphincter tone
Sexual dysfunction
What clinical syndrome would arise from a cord hemisection / BROWN SEQUARD
Ipsilateral reduced power (corticospinal tract), vibration and proprioception (posterior or dorsal column)
contralateral reduced pain / temperature and light touch (spinothalamic tract).
What is the most common cause of a brown sequard syndrome?
Penetrating injury or facet dislocation in a RTA
What is the effect of a posterior cord lesion (loss of dorsal tract)
tingling, numbness, electric shock like syndrome
clumsiness
on examination: sensory ataxia, loss of positional sense, vibration sense and 2-point discrimination below the level of the lesion
Brown-sequard syndrome