Eye Basics, Movements and Visual Fields

Question 1

Outline the actions of the different eye muscles controlled by CNIII?

Answer 1

Superior Rectus: Up
Inferior Rectus: Down
Middle Rectus: Adduction

Inferior Oblique: Extorsion, elevation and abduction
Superior Oblique: Intorsion, depression and abduction

Levator palpebrae superioris: Raises the eyelid

Iris: Constricts and dilates the pupil

Obliques love to abduct!

Question 2

Outline the actions of CNIV?

Answer 2

Trochlea nn: controls the superioir oblique

Superior Oblique: Intorsion, depression and abduction

Question 3

Outline the actions of CNVI?

Answer 3

Abducent nn: Controls lateral rectus which abducts

Question 4

Outline the visual pathway?

Answer 4

Optic nn
Optic Chaism
Optic tract (superior and inferior fibres together)
Geniculate nucleus (fibres have twisted Sup are now medial)
Superior retinal fibres run through parietal lobe.
Inferior retinal fibres run through the temporal lobe.
Join together and re twist to form the geniculocalcarine tract.
Travels to the occipital lobe broadman’s area 17.