CN VI: Abducens Nerve

Question 1

What type of axon?

Answer 1

General somatic efferent

Question 2

What is the function of VI?

Answer 2

Lateral rectus muscle (ipsilateral)

Question 3

Where does VI leave the brainstem?

Answer 3

Caudal pons

Question 4

What happens with an injury to VI?

Answer 4

Affected eye deviates medially (medial strabismus)

Question 5

What is the function of the MLF (medial longitudinal fasciculus)?

Answer 5

Allows coordination of head and eye movement

Question 6

What does the MLF connect?

Answer 6

Nuclei of CN III, CN IV, and CN VI

Question 7

What happens with an injury to the nucleus of VI?

Answer 7

Medial strabismus (eye leans medially)

Trouble gazing to the side of lesion with both eyes because no internuclear neurons for eye coordination

Question 8

What happens with a lesion to the MLF?

Answer 8

Eyes cannot coordinate so could have one eye moving laterally while other cannot know to move medially

Question 9

Scanning:

Answer 9

Horizontal: PPRF
Upward: MLF

Question 10

Track impulse for scanning/tracking.

Answer 10

Frontal eye field -> PPRF -> CN VI an III