Neuro: 3.05 - Corticobulbar Tract And Review Of Brainstem

Front 1

What is the function of the Corticonuclear / Corticobulbar Tract?

Back 1

Controls muscles of head and face

Front 2

Where does the Corticonuclear Tract originate? Project to?

Back 2

- Origin: Precentral Gyrus
- Fibers pass with corticospinal tract fibers through corona radiata, internal capsule and cerebral peduncle

Front 3

Where do the Corticonuclear Tract fibers terminate?

Back 3

Brainstem motor nuclei:
- CN V (bilateral)
- CN VII (contralateral)
- CN XII (contralateral tongue)
Nucleus Ambiguus (bilateral)
- CN IX
- CN X (soft palate, pharynx, larynx)
Accessory Nucleus (bilateral)
- CN XI

Front 4

What happens if there is a lesion to the cortical or internal capsule?

Back 4

- Simultaneously affect corticospinal tract and corticonuclear tract
- Contralateral hemiplegia and CN VII and CN XII signs
- CN VII - contralateral loss of movement on lower half of face
- CN XII - tongue points toward CN XII that is receiving no input (actually pointing away from brain lesion)

Front 5

What is Pseudobulbar Palsy?

Back 5

Bilateral lesion of Corticobulbar/Corticonuclear Tract

Front 6

What are the symptoms of a bilateral lesion of the Corticonuclear tracts? Na,e?

Back 6

- Dysphagia - difficulty swallowing
- Dysarthria - difficulty articulating words
- Paresis of tongue - weakness
- Loss of emotional control - emotional incontinence
* Pseudobulbar Palsy (UMN lesion) - similar to Bulbar Palsy (LMN lesion) *

Front 7

What are the potential causes of Pseudobulbar Palsy?

Back 7

- Brainstem infarct
- ALS
- MS

Front 8

How can you distinguish between Bell's Palsy and a Corticonuclear Tract lesion?

Back 8

- Bell's: 1/2 of forehead can wrinkle - entire half of face cannot move (LMN lesion) - R picture
- Corticonuclear Tract Lesion: all of forehead can wrinkle - only 1/4 of face cannot move (UMN lesion) - L picture

Front 9

What is wrong with this man?

Back 9

- Corticonuclear Tract - UMN lesion
- Entire forehead can move because upper half of face receives bilateral innervation
- Lower part of face only receives contralateral innervation

Front 10

What is wrong with this man?

Back 10

- Bell's Palsy - CN VII / LMN lesion
- Only half of forehead can move because bilateral innervation has been cut in CN VII

Front 11

What happens to the tongue, if the Corticonuclear Tract (UMN) is lesioned?

Back 11

Tongue deviates away from lesioned side (but points to CN XII that is not receiving input)

Front 12

What happens to the tongue if CN XII (LMN) is lesioned?

Back 12

Tongue deviates toward side of lesion

Front 13

If a patient is having problems with eye movements, what part of the brainstem is probably affected?

Back 13

Usually midbrain

Front 14

If a patient is having problems with mastication, facial expression, salivation, lacrimation, etc., what part of the brainstem is probably affected?

Back 14

Pons

Front 15

If a patient is having problems with salivation, sneezing, respiration, etc., what part of the brainstem is probably affected?

Back 15

Medulla

Front 16

If a lesion in the brain is more medial, what is probably affected?

Back 16

Motor

Front 17

If a lesion in the brain is more lateral, what is probably affected?

Back 17

Sensory