Muscle Tone

Question 1

Normal postural tone

Answer 1

Continuous state of mild contraction or a state of preparedness in the muscle

Question 2

Normal postural tone characterised by

Answer 2

1. Effective stabilisation at axial and proximal joints
2. Ability to move against gravity and resistance
3. Ability to maintain limb in position
4. Balanced tone between balanced and antagonistic muscles
5. Easily shifting between stability to mobility and reverse
6. Allows postural adjustment to movement

Question 3

Muscle Tone

Answer 3

Degree of tension (contraction) in a skeletal muscle

Question 4

3 factors determining muscle tone

Answer 4

1. Elastic properties of connective tissue
2. Visco-elastic properties of muscle fibers
3. Motor unit activity

Question 5

Assessment of muscle tone influenced by

Answer 5

1. Speed
2. Effort
3. Emotional stress
4. Temperature
5. Fatigue
6. Position of head
7. Sensory stimulation

Question 6

What can be observed in Ataxia?

Answer 6

1. Decomposition of movement
2. Dysmetry
3. Disdiakokinesia
4. Intension tremor
5. Nystagmus
6. Heel-knee-shin test

Question 7

Causes of fluctuating muscle tone

Answer 7

1. Extra-pyramidal damage
2. Damage to spinal cord level and reflex arch
3. Chronic muscle atrophy
4. Psychogenic causes

Question 8

Extra-pyramidal damage

Answer 8

1. Tremors
2. Pill-rolling tremor
3. Senile tremor
4. Intention tremor
5. Athetosis
6. Myoclonus
7. Ballismus
8. Dystonia

Question 9

Abnormal muscle tone 1

Answer 9

Hyper-tonia

• Increased resistance to passive stretch and movement
• Hyperactive reflexes
• Changes in mechanical structures

Types :

1. Spasticity
2. Rigidity
3. Dystonia
4. Clonus
5. Spasms

Question 10

Abnormal muscle tone 2

Answer 10

Hypo-tonia
Associated with:
1. Weakness
2. Atrophy
3. Absent/ decreased reflex responses

Types :

1. Flaccidity
2. Hypotony
3. Ataxia

Question 11

Causes of abnormal muscle tone

Answer 11

Hyper-tonia

1. Secondary to CNS pathology (stroke, trauma)
2. Changes in ascending tracts inhibiting motor neurons

Hypo-tonia

1. Cerebellum pathology
2. Abnormality in lower motor neuron
3. Neuromuscular junction pathology
4. Muscle pathology

Question 12

Lower motor neuron lesions

Answer 12

1. Weakness(paresis)
2. Waisting(atrophy)
3. Flaccidity
4. Low muscle tone
5. Suppressed or absent reflexes

Question 13

Upper motor neuron lesions

Answer 13

1. Spasticity
2. Overactive stretch reflex
3. Hyperactivity of motor neurons (clonus)
4. Weakness of specific movement

Question 14

Upper motor neuron neural control

Answer 14

1. Motor cortex
2. Descending motor tracts
3. Anterior horn of spinal cord grey matter
4. Additional brain areas

Question 15

Lower motor neuron neural control

Answer 15

Motor unti:

1. Motor neurons
2. Motor nerve fibers
3. Spinal nerves
4. Muscle fibers it supplies