Movement Pathways and centres

Question 1

Name the upper motor neurons

Answer 1

• Corticospinal= Cortex to spine (spinal nerves

- Corticobulbar= Cortex to brainstem (cranial nerves)

Question 2

What are the functions of upper motor neurons

Answer 2

• Influence lower motor neurone activity
• Modify local reflex activity
• Superimpose more complex patterns of movement- co-ordination action of LMN for different spinal nerves, different muscle groups

Question 3

How do UMN pass through the corticospinal pathway?

Answer 3

1) Cerebral cortex
2) Precentral gyrus
3) Internal capsule (post limb/genu)
4) Cerebral peduncles
5) Pons
6) Pyramids (decussation)
7) Lateral corticospinal tract

Question 4

What would happen if the corticospinal tract was damaged?

Answer 4

• Initially: flaccid paralysis of opposite limbs, loss of reflexes
• After several days/week: motor function recovers but hypertonia
• Long term: Spasticity, hyperreflexia, permanent inability to carry out fine movements of hands & feet

Question 5

Where do the descending fibres of the body and face pass in the internal capsule?

Answer 5

face=genu

body= posterior limb

Question 6

What runs in the lateral corticospinal tract?

Answer 6

-L= Legs, arms, trunk

Question 7

Describe the corticobulbar pathway

Answer 7

• Influences LMN cranial nerve motor nuclei
• Fibres originate laterally within pre-central gyrus
• Innervation of LMN mainly bilateral

Question 8

How does the hypoglossal nerve differ from other cranial nerves

Answer 8

Only served by contralateral nucleus

Question 9

If there is a lesion at the level of the stylomastoid foramen where will there be paralysis?

Answer 9

Ipsilateral face

Question 10

Are the fibres of the facial nerve bilateral or unilateral?

Answer 10

Upper= bilateral
Lower= contralateral

Question 11

What would be seen in the face if there was a lesion at the level of the internal capsule?

Answer 11

Paralysis of lower face on contralateral side e.g haemorrhage