Motor System Flashcards
What is the motor system split into?
Upper motor neurones (UMN)
Lower motor neurones (LMN)
Where are upper motor neurone cell bodies found?
Primary motor cortex
Where are lower motor neurone cell bodies found?
Brainstem
- CN III nuclei
- CN IV nuclei
- CN V nuclei
- CN VI nuclei
- CN IX, X, XI nuclei
- CN XII nuclei
Ventral horn of spinal cord
What state are LMNs in most of the time?
Inhibited state
What are signs of an upper motor neurone lesion?
Weakness
Hypertonicity
Hyperreflexia
Upgoing plantars
What are the signs of a lower motor neurone lesion?
Weakness Wasting Hypotonia Areflexia Fasciculations
What is the main tract of the motor system?
Lateral corticospinal tract
Describe the lateral corticospinal tract?
- Passes from primary motor cortex through the corona radiata
- Passes into internal capsule
- Enters brainstem through cerebral peduncles
- Decussates at the medullary pyramids
- Travels in the lateral corticospinal tract
- Synapses at the level
- Passes to distal muscle
Which tract is used for proximal muscle?
Ventral corticospinal tract
Draw out the facial nerve neurones
See notes
Where does the upper face receive innervation from?
Both sides
Where does the lower face receive innervation from?
Contralateral side
What happens when there is a lesion of the facial nerve UMN?
Paralysis of contralateral lower quadrant
What happens when there is a lesion of the facial nerve LMN?
Paralysis of ipsilateral half of face
