Eye Movements Flashcards
Vertical gaze
Controlled by the Rostral nucleus of the medial longitudinal fasciculus (MLF).
Located in the midbrain
Horizontal gaze
Controlled by the Paramedian pontine reticular formation.
Located in the Pons
MLF connecs
III, IV and VI CN nuclei
MLF is
Medial long fasciculus
Why does MLF connect the III, IV and VI CN nuclei?
To coordinate eye movements
Double vision is caused by
Damage in a cranial nerve innervating a muscle.
Cerebellar problems.
(If it persists with a single eye = psychiatric)
Superior rectus movements
Supradduction + adduction
Lateral rectus movements
Abduccion
Inferior rectus movements
Infradduction + adduction
Moves the eye down
Inferior oblique movements
Supradduction + adduction
Medial rectus movements
Adduction
Superior oblique movements
Infradduction + adduction
Rotates the eye
Moves the eye down + lateral
Elevation of the eyelids
Tarsal muscle (S innervation)
Levator palpebrae superioris muscle (III CN)
Horner syndrome cause
Damage of Tarsal muscles or its innervation
Horner’s syndrome manifestations
Ptosis (dropping of the upper eyelid)
Myosis (small pupil size) as we lose sympathetic tone
Enophthalmos (posterior displacement of the eye, retracted)
Damage to III CN or to Levator palpebrae muscle manifestations
Ptosis
Midriasis
Weakness in muscles innervated by the III CN
Differences between III CN damage and Horner syndrome
III vs Horner
Pupillary size: large (midriasis) / small (miosis)
Response to light: depressed / normal
Eye movements: weakness in muscles innervated by III CN / normal
Who gives the tone (pupils larger/smaller)?
Sympathetic system
Who controls the reaction to light?
Parasympathetic system
(reaches the eye by exiting Edinger-Westphal nucleus in midbrain along with the III CN. Its effect is to cause miosis)
Dilated pupil can be caused by
Peripheral damage to nerve, not urgent (expected symptom)
Brain hemorrhage or herniation, and as the pupil is contracted, this means it is advanced = very urgent! (III CN compressed)
Throchlear nerve damage symptoms
When they tilt their head towards the side of the lesion, the affected eye won’t tilt with the head as this is an effect of the superior oblique, and its not working properly.
Tilt towards the other side will be accompanied by normal eye rotation.
Movements controlled by the cortex
Smooth pursuit movements
Saccadic movements
Smooth pursuit movements - cortex regions
Frontal, parietal, temporal lobes (esp: parietal)
Smooth pursuit movements - movement
Voluntary
Smooth
Both eyes in = direction (exc: approaching smt to eye)
Precise and fast
Unconsciously, predictive
Saccadiac movements - cortex regions
Frontal lobe
Saccadiac movements - movement
We don’t look at faces as a whole -> patterns
Constantly moving the eyes (little tiny movements) to look at the different parts of the face
