Posture and Locomotion Flashcards Preview

MD1 Neuroscience > Posture and Locomotion > Flashcards

Flashcards in Posture and Locomotion Deck (28):
1

What is a decerebrate posture?

Upper and lower limbs extend

2

What are two postural signs of damage to the brainstem?

Decerebrate
Decorticate

3

What is a decorticate posture?

Upper limbs flex
Lower limbs extend

4

Which limbs does the rubrospinal tract contribute to in humans?

Upper limbs only

5

What limb movements does the reticular formation influence?

Extension of upper and lower limbs

6

Where is the reticular formation?

Pons and medulla

7

What limb movements does the red nucleus influence?

Flexion of upper limbs

8

Where is the red nucleus?

Midbrain

9

What is the role of higher cortical centres on the reticular formation and red nucleus in terms of limb movement control?

Inhibits their outputs

10

What position does a lesion above the midbrain cause, and why?

Decorticate
Remove inhibition to reticular formation and red nucleus
Lower limbs extend because of reticular formation influence
Upper limbs flex because
- Red nucleus has larger effect than reticular formation
- Flexors of upper limb stronger than extensors

11

What position does a lesion at the midbrain cause, and why?

Decerebrate
Remove inhibition to reticular formation
Cut red nucleus itself
Upper and lower limbs extend because of reticular formation influence

12

What is the Babinski sign?

Fanning of toes (upwards plantar flexion) rather than curling of toes in response to noxious stimulus on sole of foot

13

Up to what age is the Babinski sign normal?

12-24 months of life - until child gets good at walking

14

How are upper motor neuron lesions for cranial nerve lesions identified?

Pattern of loss, rather than LMN/UMN signs seen with spinal motor output

15

Which non-ocular lower motor neurons (cranial nerves) receive bilateral corticobulbar innervation?

All except those innervating lower face and tongue

16

Which motor neuron is affected if there is weakness in the inferior muscles of the face only on one side?

UMN on contralateral side

17

Which motor neuron is affected if there is weakness in all the muscles on one side of the face?

LMN on ipsilateral side

18

Why is only the lower half of the face affected when there is an upper motor neuron lesion?

Forehead receives bilateral input from cingulate motor area, and contralateral input from primary motor cortex
If UMN lesion on one side, input from cingulate motor area on contralateral side still present, so control of forehead remains
Rest of face receives only contralateral input from primary motor cortex, so if UMN lost > no input

19

What are the first movements that occur when you are going to abduct a leg?

Postural adjustments in anticipation of activity > move body weight to other leg

20

When pulling on a handle on a wall, what happens first?

In anticipation of change in position, calf muscles contract to stabilise body

21

When does locomotor activity become present?

Very early in life

22

Where is the pattern for locomotor activity?

Spine

23

Which muscle group bears weight?

Extensors - no weight bearing when you flex

24

When is useful work done?

During extension

25

How do decerebrate cats increase speed when treadmill speed is increased?

Only source of input from muscle sense
Spinal circuits tell muscles to speed up because of pattern of activation detected by muscle spindles

26

What are some abnormal gait patterns associated with CNS disorders?

Ataxic gait
Choreiform gait
Hemiparetic gait
Parkinsonian gait

27

What is an ataxic gait?

Unsteady, uncoordinated walk
Wide base
Feet thrown out
Come down first on heel then toes with double tap

28

What is a choreiform gait?

Irregular, jerky, involuntary movements in all extremeties

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