The structure and function of the descending tract Part 3 Flashcards
How is damage in the motor pathways located?
Symptoms indicate which pathway(s) have been interrupted
What does level damage dictate?
Severity of the symptoms
What does higher level damage of the motor pathways mean?
Closer to the brain
What does higher level damage of the motor pathways show?
Increased % body with motor deficit
What does damage to the trunk of upper neurons between the upper and lower limbs result in?
Paraplegia
Damage to what results in paraplegia
damage to the trunk of upper neurons between the upper and lower limbs
What is paraplegia
loss of motor function in the lower body and the lower limbs
What does damage to the trunk of upper neurons above the upper and lower than the brain result in?
tetraplegia
What is tetraplegia
Loss of voluntary movement in both upper limbs and upper body and lower limbs
What does lower level neuron tract damage result in (deficit)
Specific deficit
Where only a small region of muscles are affected while the rest functioning normally
What does higher level neuron tract damage result in ?
Release where there may be:
New patterns of activity
Normal function
Damage in spinal cord but normal lower motor neuoron function
What causes upper motor neuron syndrome?
Damage to the descending motor pathways at any point
What areas of the motor system are commonly damaged? Why?
Upper motor neurons
Large cortical areas or long pathways
How is the motor system arranged?
In a topogrophical arangement
What does topographical mean?
Where area is related t to physical position
What causes lower motor neuron syndrome?
Damage to the alpha motor neurons that innervate skeletal muscle
What does lower motor neuron syndrome affect?
Small group of muscles
What are the symptoms of upper motor neuron syndrome
Paralysis of movements Increased muscle tone (hypertonia) - maintenance of muscle mass and there is no muscle atrophy Hyperactive stretch reflexes Extensor plantar reflex (Babinski Sign) Reduction in superficial reflexes
What are the symptoms of lower motor neuron syndrome
Loss of innervation to the muscles
Paralysis of muscles
Hypotonia (loss of muscle tone) and atrophy of muscles- muscle wasting
Fasciculations and fibrillations
Loss of stretch reflexes but superficial reflexes are maintained
What elicits superficial reflexes
Gentle cutaneous stimulation
What elicits extensor plantar reflex
Sharp object across the plantar aspect of the foot
What is the name for abnormal extensor plantar reflex ?
Babinski reflex
What are the signs for the Babinski reflex
Fanning of the toes, extending of the toes towards the dorsal aspect of the foot
When is the babinski reflex seen as normal and why?
For children under two years as the corticospinal tract is not fully myelinated
