Lecture 59 - Extraocular Movements Flashcards
Cranial nerve _____ is the only one that exits the brainstem Posteriorly AND it’s the only cranial nerve that _____ before leaving the brainstem.
CN IV
Decussates
CN _____ innervates the Constrictor Pupilae and the Ciliary muscles. This innervation is ________ (sympathetic or parasympathetic?) and runs on the outside of the nerve (first to be compressed if there’s something like an aneurysm).
CN III
Patients with a IV nerve palsy will show an eye that’s “up and out.” When the eye is Adducted, it will move _____ bc of unopposed action by the inferior oblique.
Toward which side, ipsilateral or contralateral to the lesion, will a patient tilt their head to compensate for this palsy?
Upward (remember the Superior Oblique moves the eye downward when Adducted)
Toward the Contralateral side
The MLF interconnects CN III and IV nuclei with the _______ and _______ nuclei, allowing for coordinated Horizontal gaze.
CN VI and CN VIII nuclei
The PPRF (Paramedian Pontine Reticular Formation) provides inputs from the Cortex to the _______ nucleus. This also facilitates coordinated horizontal gaze.
Aducens (CN VI)
Is it the Contralateral or Ipsilateral side of the cortex that inputs into the PPRF?
If there is a lesion in the Frontal Eye Field, what would the issue with eye movement be?
Contralateral
Issue would be with Volitional horizontal gaze to the Contralateral side
Oculovestibular reflex refers to eye movements when turning your head. How does it work?
Keep in mind adding Warm water to the ear simulates turning the head to that direction (cold water does the opposite).
When you turn your head, you’ll have FAST nystagmus toward the side you’re turning and SLOW nystagmus toward the opposite side.
The _____ (rostral or dorsal?) Interstitial nucleus of the MLF coordinates Downward gaze, while the _____ (rostral or dorsal?) Interstitial nucleus of the MLF coordinates Upward gaze.
Rostral
Dorsal
