Motor Function Flashcards Preview

Neurology > Motor Function > Flashcards

Flashcards in Motor Function Deck (33)
Loading flashcards...
1
Q

Which has more prominent muscle wasting, myopathies or neurogenic wasting (conditions where muscles have been denervated)

A

Neurogenic wasting

2
Q

Where do most fibres in the pyramidal tract decussate

A

Medulla - most fibres decussate here to form the lateral corticospinal tracts in the spinal cord

3
Q

What do fasciculations indicate

A

LMN lesion - generally proximal and severe, especially at anterior horn cell level

4
Q

A patient has wasting of the small muscles of the hand with wasting of the thenar eminence.

Where is the lesion

A

Proximal lesion - anterior horn cell, root (C8/T1), or plexus

5
Q

A patient has wasting of the small muscles of the hand but the thenar eminence is spared.

Where is the lesion

A

Peripheral nerve lesion - ulnar neuropathy

6
Q

A patient has wasting of the thenar eminence only.

Where is the lesion

A

Peripheral nerve lesion - median neuropathy

7
Q

What is the stretch reflex

A

Passive stretch of a muscle –> afferent impulses to spinal cord –> activates the motor neurone –> reflex contraction

This response causes normal muscle tone. Interruption of this reflex arc (eg. LMN damage) causes flaccidity

8
Q

What is the characteristic quality of hypertonia caused by UMN damage

A

Clasp knife rigidity

9
Q

What is the supinator catch

A

A miniature version of the clasp-knife effect - elicited by supinating and pronating the forearm. May be the only feature of a subtle UMN lesion

10
Q

What is pronator drift

A

The affected limb will pronate and drift downwards when arms outstretched, palms facing upwards and the eyes are shut.

A sign of mild upper limb UMN damage

11
Q

On a patient being told to raise their leg, no movement is made and no contraction is seen.

What is the grade of power using the Medical Research Council Scale

A

0 - no contraction

12
Q

A patient is able to raise their leg against resistance however they are easily overpowered.

What is the grade of power using the Medical Research Council Scale

A

4 - active movement against gravity and resistance

13
Q

A patient is able to raise their leg off the bed when asked however they cannot hold it their against resistance

What is the grade of power using the Medical Research Council Scale

A

3 - active movement against gravity

14
Q

Where is muscle weakness in a patient with motor polyneuropathy

A

Distal muscles

15
Q

What is meant by a “pyramidal distribution” of muscle weakness

A

Greater weakness of extensors than flexors in the upper limbs, and greater weakness of flexors than extensors in the lower limbs.

Caused by UMN weakness

16
Q

A patient has left sided ataxia (loss of coordination).

Where is the most likely location of the lesion

A

Left-sided cerebellar lesion

17
Q

What causes past-pointing

A

Dysmetria - Inability to judge distances

18
Q

How do the reinforcement manoeuvres work to elicit a reflex

A

They increase the sensitivity of stretch receptors throughout the body

19
Q

How do UMN lesions cause brisk reflexes

A

As a result of loss of supraspinal inhibition.

The same reason that UMN lesions cause increased tone

20
Q

What causes clonus

A

UMN lesions causing loss of supraspinal inhibition

21
Q

What is a pendular reflex associated with

A

Cerebellar disease - causing the reflex to swing back and forth

22
Q

What is a slow relaxing reflex associated with

A

Hypothyroidism

23
Q

In trying to elicit the Babinksi reflex, the patients big toe dorsiflexes and the other toes fan out.

What is this and what causes it

A

A positive Babinski reflex caused by a UMN lesion

24
Q

What gait is caused by spastic paraparesis

A

Scissoring gait - UMN lesion affecting both legs

25
Q

What condition may cause a scissoring gait

A

Spastic cerebral palsy

26
Q

What gait is caused by spastic hemiparesis

A

Circumduction gait - UMN lesion affecting one side of the body

27
Q

What condition may cause a circumduction gait

A

Stroke

28
Q

What gait is caused by bilateral foot drop

A

Steppage gait - LMN lesion affecting both legs

29
Q

What condition may cause steppage gait

A

Guillain-Barre syndrome
Herniated lumbar disk
MS

30
Q

What gait is caused by a cerebellar lesion

A

Broad-based, staggering gait - unable to walk heel-toe

31
Q

What are the features of Parkinsonian gait

A

Stooping posture
Rigid shuffling gait
No arm swing

32
Q

What conditions may cause a patient to have to support their head with their hand under their chin

A

Due to weakness of neck extension - relatively uncommon

Myasthenia gravis
Polymyositis
Motor neurone disease

33
Q

What causes truncal ataxia (if severe may mean the patient is unable to sit unsupported)

A

Damage to the cerebellar midline (vermis)