129 - Spinal Cord Compression Flashcards Preview

Year 1 > 129 - Spinal Cord Compression > Flashcards

Flashcards in 129 - Spinal Cord Compression Deck (67):

What are the 5 components of a spinal reflex arc?

  1. Sensory receptor
  2. Afferent path to CNS
  3. Synapse within the CNS
  4. Efferent path from the CNS
  5. Effector



Which side of the spinal cord does sensory information enter?

The dorsal root


Which part of the spinal cord does motor information leave?

The ventral root


What are the main musculoskeletal sensory receptors?

  • Muscle spindles
  • Golgi tendon organs
  • Joint receptors


Apart from musculoskeletal receptors, what other sensory receptors may be involved in the spinal reflex?

  • Nociceptors
  • Temperature
  • Pressure
  • Light 
  • Sound



What is the primary receptor involved in the myotatic reflex?

Muscle spindle


What subgroup of neurones are utiliesed in the afferent pathway of the mytatic reflex?

Group 1a


What group of neurones are used to carry the motor information of the myotatic reflex?

Alpha motor neurones


What is the name given to a muscle when it is the effector muscle and contains the muscle spindle?

Homonymous muscle


What cell acts as an inhibitory regulator of the myotatic reflex arc?

Renshaw cells acting on the alpha motor neurones


What reflex uses golgi tendon organs?

Inverse myotatic reflex


What neurone group is activated in the inverse myotatic reflex?

Group 1b neurones



What happens to the homonymous muscle when the inverse myotatic reflex is activated?

The alpha motor neurones are inhibited and therefore the muscle is not activated.


When is the inverse myotatic reflex activated?


During prolonged contraction or stretching of a muscle


What is the function of gamma motor neurones?

Contraction of the muscle spindle to regenerate tension within it


What are the sensory organs involved in the flexion (withdraw) reflex?

Nocicepters (free nerve endings)


What groups of neurones are involved in the transmitting of pain sensation in the flexion reflex?

  • Group 3 - myelinated
  • Group 4 - unmyelinated


What class of motor neurone is involved in the flexion reflex?

Alpha motor neurones


What is the main difference between the myotatic and withdraw reflex?

  • Myotatic reflex is mono-synaptic, involving one group of muscles
  • Withdraw reflex is polysynaptic, involving several groups of muscles to produce the withdrawal


What 4 areas of the CNS are required for voluntary movement?

  1. Cerebral cortex
  2. Brainstem
  3. Descending tracts of the spine
  4. Ascending tracts of the spine


What is the corticospinal tract of the spine involved with?

Control of fine movements


Describe the pathway of the corticospinal pathway

  • Arises from the cerebral cortex
  • Passes through medullary pyramids
  • Terminates in the spinal cord


How is the corticospinal tract organised?

It is arranged somatotopically into the cortical homunculus


Which structures do the neurones of the corticospinal tract pass through between the cerebral cortex and medullary pyramids?

  • Cerebral cortex
  • Corona radiata
  • Internal capsule
  • Crus cerebri in the midbrain
  • Pons
  • Medulla


What is the fate of the majority of the neurones of the corticospinal tract on the medulla?

The decussate onto the contralateral side to descend in the lateral corticospinal tracts


What neurones constitute the anterior corticospinal tract?

Those neurones that do not decussate in the medulla


Which areas of the brain do fibres of the corticospinal pathway arise from?

  • Primary motor cortex
  • Primary somatosensory area
  • Premotor and supplementary motor areas
  • Posterior parietal cortex



What test is used to show damage to the corticospinal tract?

Babinski sign


What happens in a positive babinski test?

  • Extension of the great toe
  • Rest of toes fan out



What are the functions of the primary somatosensory cortex (parietal)?


  • Recieve ascending information from the thalamus
  • Hold sensory homunculus
  • Send descending fibres to sensory regions
  • Filter irrelevant sensory information


What symptom may present itself if there is damage to the primary somatosensory cortex?

Agraphesthesia (difficulty recognising letters or number drawn in the skin)


What are the functions of the premotor area (frontal)?


  • Planning of intended movements
  • Movements that require visual guidance


What is the main function of the supplementary motor area?

Coordination of voluntary movements


What is the function of areas 5 & 6 of the posterior parietal cortex?

Integration of attentional information



What is a symptom of damage to the posterior parietal area?

Anosognosia - "denial of disability"


What is apraxia?

Inability to produce a specific motor act even though the sensory and motor pathways are intact


What is ideomotor apraxia?

A person cannot execute a specific movement upon request, but can recognise what the movement is. 

They may also spontaneously produce the movement


What is ideational apraxia?

The person cannot conceptualise the movement required for a specific task


What sensations are transmitted via the spinothalamic tract?

  • Pain
  • Temperature


What sensations are carried in the dorsal columns?

  • Soft touch
  • Prioprioception


What are the differences between upper and lower motor neurones?

Upper motor neurones:

  • Innervate lower motor neurones
  • Do not project directly onto muscles
  • Glutamatergic
  • Arise from the brain

Lower motor neurones:

  • Innervate skeletal muscle
  • Release acetylcholine at the NMJ
  • Alpha and gamma subtypes
  • Arise in the brainstem and spinal cord


What are the signs of a lower motor neurone lesion?

  • Hyporeflexia
  • Fasciculations
  • Muscle atrophy
  • Denervation



What are the causes of a lower motor neurone lesion?

  • Trauma
  • Viral infections such as polio


What are the classic signs of an upper motor neurone lesion?

  • Paralysis/ weakness of movement of affected muscles
  • Hyperreflexia
  • Hypertonia with spasticity
  • Positive babinski sign


What would you expect to see immediately following an upper motor neurone lesion?

  • Flaccid paralysis 
  • Hypotonia
  • Loss of myotatic reflex

The opposite of the long term effects


What is Brown-Sequard Syndrome?

Hemisection of the spinal cord


What happens to proprioception and 2 point discrimination on the ipsilateral and contralateral side in a Brown Sequard lesion?

Ipsilateral side:

  • Priprioception and 2 point discrimination lost below the level of the lesion

Contralateral side:

  • Proprioception and 2 point discrimination are unaffected


How does a Brown Sequard lesion affect temperature and pain sensation?

They are both lost on the contralateral side to the lesion.

This is usually 1 or 2 segments below the lesion


What type of motor neurone symptoms are seen with Brown Sequard syndrome?

  • Upper motor neurone symptoms seen below the level of the lesion on the ipsilateral side
  • Lower motor neurone symptoms seen at the level of the lesion on the ipsilateral side


What are the causes of Brown Sequard Syndrome?

  • Fracture dislocations of the vertebrae
  • Tumour
  • Missle wounds



Define dermatome

The area of skin supplied by the right and left dorsal roots of a single spinal root


What are the causes of weakness?

  • Damage to the motor pathway
  • Neuromuscular junction disease
  • Muscle disease
  • Arthritis or joint disease
  • Endocrine disorders
  • Systemic diseases
  • Fatigue



Define monoparesis

Weakness of 1 limb


Define paraparesis

Weakness of both legs


Define hemiparesis

Weakness of 1 side of the body


Define quadraparesis

Weakness of all 4 limbs


Define hemiplegia

Paralysis of 1 side of the body


Define paraplegia

Paralysis of both legs


What are the 3 classic signs of upper motor neurone damage to the lower crainal nerves?

  1. Dysarthric
  2. Slow tongue movements
  3. Brisk jaw jerk


Which part of the motor pathway is affected in Amyotrophic Lateral Sclerosis (Motor neurone disease)?

Upper motor neurones:

  • Corticospinal tract
  • Corticobulbar tract

Lower motor neurones:

  • Cranial nerve nuclei affecting speech and swallowing
  • Loss of anterior horn cells



What is the incidence of Amyotrophic lateral sclerosis?

2 in 100,000


What age does amyotrophic lateral sclerosis usually begin?

Around 55 years old


What drugs may produce myopathy?

  • Statins
  • Steroids
  • Anti-viral drugs
  • Chloroquine



What are the symptoms and histological signs of polymyositis?

  • Proximal muscle wasting
  • No rash
  • Inflammatory cell infiltrate in muscle fibres on histology


What are the symptoms and histological signs of dermatomyositis?

  • Rash over hands and face
  • Associated with malignancy in adults
  • Inflammatory cells surrounding blood vessels



What are the symptoms of inclusion body myositis?

  • Proximal leg muscle and long finger flexor weakness
  • Elderly



What are the symptoms of cauda equina?

  • Bilateral sciatica
  • Saddle and genital anaesthesia
  • Sphincter and sexual dysfunction