Cranial Nerves lll, lV, and Vl with vocab Flashcards
What is the primary function of the medial longitudinal fasciculus (MLF)?
coordinate eye movements
A common lesion of the MLF could be caused by what disease that in turn affects CN lll, lV, and Vl?
MS
With a lesion of the MLF the patient wont be able to laterally gaze but will have no abnormaility noted on convergence, why is this?
lateral gaze requires both CN lll and Vl whereas convergance only requires function of CN lll bilaterally
What do the 2 separate supranuclear pathways for eye movement control?
- Frontal Lobe =
- Occipital Lobe =
- Saccadic (rapid/darting) eye movement
- smooth or following eye movements
What is a nystagmus?
involuntary eye oscillations
Disease of which CN will have parasympathetic manifestations such as eyelid ptosis and corectasia?
CN lll
Disease of which CN will cause difficulty for the patient when looking down and in??
CN lV
Disease of which CN will the cause the inability to laterally deviate the eye on the same side (ipsilateral) lesion?
CN Vl
Disease of CN ll Will diminish what?
pupilloconstriction Bilaterally
What would cause the pupil to be in fixed dialation?
Loss of diencephalon or midbrain function
(bilaterally would indicate patient is brain dead)
What does paralysis of the superior tarsal muscle cause?
Ptosis
What is cormiosis?
pupilloconstriction
What does denervation of the sweat glands cause?
Facial anhydrosis (lack of sweating)
What is a sympathetic hypofunction, often due to lesions of the neck proximal to the carotid artery bifurcation that compresses acending sympathetic fibers?
Horners syndrome
What are the symptoms of Horner’s Syndrome?
- ptosis
- pupillo constriction (cormiosis)
- Facial anhydrosis on the ipsilateral side of the head
- Ipsilateral facial vasodialation
Lesions along the sympathetic pathway distal to the bifurcation of the common carotid arteries will cause only what symptoms if occuring along the internal carotid pathway?
pupilloconstriction (cormiosis) and ptosis
Lesions along the sympathetic pathway distal to the bifurcation of the common carotid arteries will cause only what symptoms if occuring along the external carotid pathway?
Vasodilation and anhydrosis
What is Enophthalmos?
inward sinking of the eyeball and the eye socket
What is a satisfactory way to assess sympathetic function in the head and face?
elicit the ciliospinal reflex
What is the ciliospinal reflex
Pinching of the skin on the patients neck and observing for brisk BILATERAL pupillodilation
Legal blindness is a __________ issue
Medical blindness is a failure to _________ _________ ___________
legal
perceive light stimulus
What does confrontation test?
Peripheral vision
What CN is thought to be the most notably conflicting with proprioceptive inputs when a nystagmus is present?
Vlll
What is the Marcus-Gunn Phenomenon
apparent pupillodilation with light introduction
(pupil consticts less than the other pupil when introduced to the same light stimulis, no actual dialation) found with swinging flashlight test
If the cup is greater than half the disc size what may this indicate specifically?
increased interocular pressure (glaucoma expected)
What do the following findings indicate?
- Blurred nerve fibers and cup
- tortuous, engorged veins and loss of venous pulsations at dic margin
- obliteration of physiological cup
- disc elevation and edema
Papilledema (swelling of optic disc)
What percent of the population has been described as having a pseudopapilledema and what ethnicity is MC?
5% (usually in blond caucasians)
Inflammation of the optic nerve or disc has similar ophthalmoscopic characteristics to papilledema, how can you tell the difference?
papilledema wont have pain and is benign and usually self resolving
If a fundiscopic exam inflammation appears to be behind the portion of the optic disc, the fundus looks normal but the patient has visual loss what is this called?
acute retrobulbar neurits
Venous engorgement along with a light reflection off of the artery and may appear shiny (silver-wiring) may indicate what?
arteriosclerosis
How can you evaluate the macula during a ophthalmascope exam?
have patient look directly into the light (insead of 15 degree angle towards the eye you took for evaluation of the other structures of the eye)
What are a collection of degenerative deposits that often appear in the fundus of elderly people?
Drusen Bodies
