Lecture 16

Question 1

What are the 2 exceptions of the Corticobulbar pathway axons?

Answer 1

1) There is only a crossed supply to the lower part of the facial motor nucleus
2) Hypoglossal Nucleus’s Genioglossus Muscle control region

Question 2

What is the general rule for corticobulbar tract innervation of cranial nerve nuclei?

Answer 2

Bilateral innervation (both hemispheres control both sides of most cranial nerve motor nuclei)

Question 3

How is the lower part of the facial nucleus (CN VII) innervated?

Answer 3

Contralaterally only

Question 4

What clinical sign results from a unilateral cortical lesion affecting CN VII?

Answer 4

Weakness of the contralateral lower face with sparing of the forehead

Question 5

How is the hypoglossal nucleus (CN XII) primarily innervated?

Answer 5

Primarily contralaterally

Question 6

What clinical sign results from a unilateral cortical lesion affecting CN XII?

Answer 6

Tongue deviates toward the weak (contralateral) side when protruded

Question 6

Describe Exception 2

Answer 6

Lower Face part is innervated by the contralateral hemisphere
- Left lower face is innervated by right hemisphere
- Right lower face is innervated by left hemisphere

Question 7

What side does the tongue curve towards when paralysed?

Answer 7

Tip of the tongue curves towards the paralysed muscle side

Question 8

What is the function of the Genioglossus muscle?

Answer 8

Pulls the tongue out
- 2 Genioglossus muscles (Left and Right )