Topic 9 & 10 Motor cortex, corticospinal tract, volintary movement , spacticity rigidity & tone

Question 1

What is meant by upper motor neuron syndrome

Answer 1

Results from a lesion to the descending corticospinal system

Negative signs

• weakness/loss of dexterity
• Loss of fractionated movement

• Positive 'signs'
– Spasticity'
– Hyperreflexia
-Increased DTR
-Clasp knife
– Clonus
– Babinski 
– Flexor and extensor spasms

Question 2

Lower motor neuron signs and symptoms

Answer 2

Negative signs

• Loss of/reduced volintary movement
• Loss of muscle tone
• Loss of reflexes

Positive signs
-Wasting/atrophy

Question 3

Define muscle tone

Answer 3

Continous and passive partial contraction of the muscles or the muscles resistance to passive stretch

The amount of tension in a muscle

Question 4

Define spasticity and rigidity

Answer 4

Spasticity
Velocity dependent increase in muscle tone resulting from hyperextensibility of stretch reflexes.

Rigidity
Non velocity dependent

Question 5

Define spasticity and rigidity

Answer 5

Spasticity
Velocity dependent increase in muscle tone resulting from hyperextensibility of stretch reflexes.

Rigidity
Non velocity dependent resistance to passive movement

Question 6

Define paresis

Define paralysis

Answer 6

Muscle weakness not related to atrophy. Inability to generate sufficient …

Question 7

Define Dystrophy

Define myopathy

Answer 7

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Question 8

Define fasiculation

Define fibrillation

Answer 8

These are symptoms of LMN injury

Fibrillation: Spontaneous twitching of individual muscle fibers.
When muscle fibers lose contact with their innervating axon but remnants of the axons near the muscle fibers remain. These individual axon fibers generate spontaneous action potentials causing individual muscle fiber’s to contract. Fibrillations are too small to be seen as a visible muscle contraction. They can only be detected with an electromyogram.

Fasciculations: visible spontaneous contractions involving small groups of muscle fibers.Damaged alpha motor neurons can produce spontaneous action potentials. These spikes cause the muscle fibers that are part of that neuron’s motor unit to fire.

Question 9

Describe the lower limb flexor synergy

Answer 9

Pelvic girdle: Elevation & retraction
Hip: Flexion, Abduction & external rotation
Knee:Flexion
Ankle: Dorsiflexion & inversion
Toes: Flexion

Question 10

Describe the lower limb extensor synergy

Answer 10

Pelvic girdle: Elevation & Retraction
Hip: Extension, adduction & Internal rotation
Knee:Extension
Ankle:Plantarflexion & Inversion
Toes: Flexion or extension