Movement of the Eyes and Reflexes

how many Extra-Ocular Eye Muscles do we have?

four rectus , 2 obliques

The cranial nerves that control the eyes are

interconnected within the brainstem by coordinating centers and fiber tracts

the eye muscles all originate from

the common tendinous ring

The rectus eye muscles all attach to their respective areas of the

sclera

all eye muscles (except for the lateral muscle & superior oblique ) are innervated by

oculomotor nerve (CN III)

the lateral rectus muscle is innervated by the

abducens (CN VI)

superior oblique muscle is innervated by

trochlear nerve (CN IV)

superior oblique muscle action

depression and intorsion

inferior oblique muscle action

elevates, abducts, extorsion

the oculomotor branches from

the superior colliculis of midbrain

the trochlear nerve branches from

the inferior colliculus of midbrain

abducens nerve branches from

the caudal lateral pons

The nerves that innervate the eyes communicate to coordinate movement via the

MLF (Medial Longitudinal Fasciculus)

vestibular cochlear (CN VIII) helps prevent

blurry vision when moving head to keep balance (medial and lateral rectus engaged)

eyes converge through

adduction by both medial rectus muscles to focus on near object

eyes diverge through

abduction by both lateral rectus muscles. shifts focus from near to far

levator papilary superioris keeps

eyelid up