CN III, IV, VI

Question 1

Location of CN II and IV

Answer 1

-lie in the midbrain just ventral to the superior & inferior colliculi respectively

Question 2

Location of CN VI

Answer 2

-lies in the caudal one half of the pons

Question 3

Edinger-Westphal Nucleus

Answer 3

• associated with CN III nucleus

- parasympathetic supply to the constrictor muscles of the iris

Question 4

Dorsal Nuclei of CN III

Answer 4

-serve the inferior rectus muscle

Question 5

Intermediate Nuclei of CN III

Answer 5

-serves inferior oblique muscle

Question 6

Medial Nuclei of CN III

Answer 6

-serves superior rectus

Question 7

Ventral Nucleus of CN III

Answer 7

-serves the medial rectus

Question 8

Central Caudal Nucleus of CN III

Answer 8

-serves the levator palpebrae superioris muscle

Question 9

The Trochlear Nucleus

Answer 9

-serves the superior oblique

Question 10

The Abducens Nucleus

Answer 10

-serves the lateral rectus

Question 11

Where does CN VI exit?

Answer 11

-pontomedullary junction

Question 12

Tarsal Muscle

Answer 12

• innervation: sympathetic by CN III
• autonomic elevation of eye lid, sympathetic innervation of pupil dilator muscles, & parasympathetic innervation of the pupil constrictor & ciliary muscles

Question 13

Ciliary Muscle

Answer 13

-changes in lens shape as the eye are converged (accommodation)

Question 14

Medial & Lateral Rectus

Answer 14

Medial: CN III
Lateral: CN VI
-move the eye globe towards the nose (adduction) or away from the nose (abduction)

Question 15

Super & Inferior Rectus

Answer 15

• CN III

- eye ball up or down

Question 16

Inferior Oblique Muscle

Answer 16

• CN III

- extorsion

Question 17

Superior Oblique Muscle

Answer 17

• CN IV

- intorsion

Question 18

Levator Palpebrae

Answer 18

• CN III

- raise eyelid (voluntary)

Question 19

Superior Tarsal Muscle (Muller’s)

Answer 19

• sympathetic nerve

- raise eyelid (involuntary)

Question 20

Sympathetic Innervation of Pupil & Tarsal Muscle

Answer 20

• Primary neurons lie in the hypothalamus, travel through lateral brainstem, synapse with secondary neurons in intermediolateral gray area of the spinal cord at C8-T2 level
• Secondary neurons send axons out the ventral root to synapse in paravertebral sympathetic gangila chain onto tertiary neurons
• Tertiary neurons send axons to travel along internal carotid artery within carotid sheath & enter vault with internal carotid artery
• join nasociliary nerve to innervate the superior tarsal muscle & the long & short ciliary nerves to innervate the dilatory muscle of the pupil

Question 21

Medial Longitudinal Fasciculus

Answer 21

-connect CN III with CN V(

Question 22

Diplopia

Answer 22

-double vision