5.1 - Lesions of the Motor System Flashcards Preview

ESA 5 - Nervous System > 5.1 - Lesions of the Motor System > Flashcards

Flashcards in 5.1 - Lesions of the Motor System Deck (19):
1

Define a positive and negative sign of a neurological lesion?

Negative sign - Loss of function or capacity

Positive sign - Emergence of a feature e.g. tremor

2

Label the cerebellar functional divisions

3

What is the general function of each functional zone of the cerebellum?

vestibulocerebellum - Balance and ocular reflexes

spinocerebellum - Involved in Error correction

Cerebrocerebellum - Movement planning and motor learning, esp visually guided movements and coordination of muscle activation

4

Label the arteries that supply the cerebellum. From which arteries are these derived?

5

Which veins drain the cerebellum and where do these veins then drain into?

Superior and inferior cerebellar veins

drain into transverse and sigmoid sinuses

6

Give 3 common causes of cerebellar dysfunction

Tumours

Cerebrovascular disease

Genetic e.g. Friedrichs ataxia

7

Give 4 possible signs of damage to the cerebrocerebellum and spinocerebellum

ataxia, dysarthria and scanning speech, hypotonia, dysdiadochokinesia, inability to learn new movements

8

Give 2 signs of damage to the vestibulocerebellum

abnormal gait with a wide stance, and loss of balance

9

Label the anatomical divisions of the cerebellum

10

describe the embryonic development which leads to the cerebellum

Neural tube forms prosencephalon, mesencephalon, and rhombencephalon

Rhombencephalon splits into metencephalon (superior) and myelencephalon (inferior) - Metencephalon forms cerebellum

11

Give 6 signs of a UMN lesion

Hyperreflexia, hypertonia, spastic paralysis, babinski sign, myoclonus, choreas

12

What is a positive and negative sign of babinski?

Positive - abduction of toes and dorsiflexion of big toe

Negative - flexion of toes

13

What does a positive babinski mean?

UMN lesion in the corticospinal tract

14

Give 4 signs of LMN lesions

flaccid paralysis, denervation atrophy, areflexia / atonia, fasciculations

15

Explain why fasciculations occur in LMN lesions

deinnervation of muscles means nACHRs have become hypersensitive to any neurotransmitter substances or molecules even vaguely similar to ACh such as those found in the blood. Results in slight muscle contractions

16

In the case of LMN lesions, when is the damage irreversible?

If the cell body is damaged, no regeneration can take place.

17

How is  micturition affected by a LMN lesion in S2-S4?

Overflow incontinence - autonomous bladder

18

Describe what spinal shock is. Why does it occur?

When descending tracts damaged, there is a recovery period of 4 - 6 weeks where there is flaccid paralysis and areflexia in the affected limbs. This is then replaced with spasticity and hyperactive deep reflexes.

It occurs because the loss of reflexes is due to loss of motor influences exerted by descending fibres. As these fibres degenerate the intact connections in the reflex circuits become dominant and show themselves as upper motor neurone signs

19