Eye movements Flashcards
What are the six extra-ocular muscles?
Lateral Rectus Medial Rectus Superior oblique Inferior oblique Superior rectus Inferior rectus
Which extra-ocular muscles are innervated by the oculomotor nerve?
Medial rectus
Superior Oblique
Inferior Oblique
Inferior rectus
Which nerve innervates the superior oblique?
trochlear nerve
Which extra-ocular muscle is innervated by the abducens nerve?
Lateral rectus
What is duction?
Eye movement in one eye
What term describes simultaneous movement of both eyes in the same direction?
Version
What is vergence?
Simultaneous movement of both eyes in the opposite direction
What is convergence?
Simultaneous adduction (inward) movement in both eyes when viewing a near object
What is saccade?
Short fast, burst up to 900 degrees/second
Voluntary and involuntary
What are the four types of saccade?
Reflexive saccade to external stimuli
Scanning saccade
Predictive saccade to track objects
Memory guided saccade
What is smooth pursuit?
Sustains slow movement (up to 60 degrees/s)
Driven by motion of a moving target across the retina
-Involuntary
What is the function of the superior rectus?
Elevation of the eyeball
Adduction
What is the function of the inferior rectus?
Depression of the eyeball
Adduction
In what position are the vertical rectus muscles aligned?
When the eye is in an abducted position.
Anterior-posterior axis of the eye is aligned with the insertion of the vertical muscles
In what position will the superior rectus elevate the eye maximally?
Abducted position
What is the function of the lateral rectus?
Abduction of the eyeball
Moves eye toward the outside of the head
What is the function of the medial rectus?
Adduction of the eyeball
Attached on the nasal side of the eye, moves eye toward the middle of the head.
What is the function of the superior oblique?
Abducting, depression and internally rotating the eye.
What is the function of the inferior oblique?
Elevate and adduct the abduct
Which muscle raises the eyelid?
Levator palebrae superioris
Which nerve innervates the levator palpebrae superioris?
Oculomotor nerve
Which specific nerve innervates the superior rectus muscle?
The superior oculomotor nerve
Which specific nerve innervates the medial, inferior rectus and the inferior oblique?
Inferior oculomotor nerve
Which position is the lateral rectus muscle best tested?
In the abducted position
Which position is the medial rectus best tested?
In the adducted position
Which position is the superior rectus best tested in?
Elevated and abducted position
Which position is the inferior rectus best tested in?
Depressed and abducted position
Which position is the inferior oblique best tested in?
Elevated and adducted
Which position is the superior oblique best tested in?
Depressed and adducted
What is supraduction?
Elevation in one eye
What is supraversion?
Elevation in both eyes
What is infraduction?
Depression in one eye
Depression in both eyes is referred to as what?
Infraversion
What is dextroversion?
Eye movements to the right
Right abduction and left adduction
What is levoversion?
Right adduction and left abduction
Eye movements to the left
What is torsion?
Rotation of the eye around the anterior posterior axis of the eye.
Which extra-ocular muscles are not affected in a third nerve palsy?
Superior oblique and lateral rectus
What is the eye movements in a patient with third nerve palsy?
Down and out considering the lateral rectus abducts and the superior oblique depresses the eyeball - over action of the two unopposed muscles.
What happens to the eyelid in a third nerve palsy?
ptosis, drooping of the eye lid as the levator palpebrae superioris is affected.
Which nerve is affected in a sixth-nerve palsy?
Lateral rectus
What happens to eye movements in a sixth nerve palsy?
Affected eye is unable to abduct and thus deviates inwards.
What is nystagmus?
Refers to the oscillatory movement of the eye
What is an optokinetic nystagmus?
Smooth pursuit and fast phase reset saccade
Which eye reflex is useful when testing the visual acuity in pre-verbal children?
Optokinetic nystagmus reflex
Observes the presence of nystagmus movement in response to moving grating patterns of various spatial frequencies.
What is the optokinetic nystagmus reflex?
Opto-kinetic Nystagmus is a form of physiological nystagmus,
triggered by the presentation of a constantly moving grating pattern.
The eyes track along the grating motion,
with smooth pursuit up to a limit,
and resets the eye position to the centre,
with a burst of fast saccade motion.
This results in cycles of slow phase smooth pursuit,
alternating with fast phase reset saccade in the opposite direction.
