CN III, IV, VI Flashcards
Location of CN II and IV
-lie in the midbrain just ventral to the superior & inferior colliculi respectively
Location of CN VI
-lies in the caudal one half of the pons
Edinger-Westphal Nucleus
- associated with CN III nucleus
- parasympathetic supply to the constrictor muscles of the iris
Dorsal Nuclei of CN III
-serve the inferior rectus muscle
Intermediate Nuclei of CN III
-serves inferior oblique muscle
Medial Nuclei of CN III
-serves superior rectus
Ventral Nucleus of CN III
-serves the medial rectus
Central Caudal Nucleus of CN III
-serves the levator palpebrae superioris muscle
The Trochlear Nucleus
-serves the superior oblique
The Abducens Nucleus
-serves the lateral rectus
Where does CN VI exit?
-pontomedullary junction
Tarsal Muscle
- innervation: sympathetic by CN III
- autonomic elevation of eye lid, sympathetic innervation of pupil dilator muscles, & parasympathetic innervation of the pupil constrictor & ciliary muscles
Ciliary Muscle
-changes in lens shape as the eye are converged (accommodation)
Medial & Lateral Rectus
Medial: CN III
Lateral: CN VI
-move the eye globe towards the nose (adduction) or away from the nose (abduction)
Super & Inferior Rectus
- CN III
- eye ball up or down
Inferior Oblique Muscle
- CN III
- extorsion
Superior Oblique Muscle
- CN IV
- intorsion
Levator Palpebrae
- CN III
- raise eyelid (voluntary)
Superior Tarsal Muscle (Muller’s)
- sympathetic nerve
- raise eyelid (involuntary)
Sympathetic Innervation of Pupil & Tarsal Muscle
- 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
Medial Longitudinal Fasciculus
-connect CN III with CN V(
Diplopia
-double vision
