Midterm - Cranial Nerve Flashcards
Amosmia
Complete loss of sense of smell
Hyposmia
Diminished sense of smell
Loss of sense of smell is commonly (bilateral/unilateral)
Bilateral
What does anosmia that is new on onset and unilateral suggest?
Intracranial mass
Dysosmia/ Parosmia
Difficulty identifying odors (considered idiopathic)
Phantosmia
Hallucination of an odor when none present (implies a problem in the olfactory cortex)
What does CN II do?
Sensory only: vision and afferent portion of pupil constriction
What is the degree of Nasal and temporal Peripheral vision of the horizontal field
Nasal : 60 Temporal: 90-110
What is the degree of superior and inferior peripheral vision of the vertical field
Superior: 50 Inferior: 70
Globally narrowed visual fields can be cause by
Primary open angle glaucoma (high pressure in the eye damages the optic nerve)
If the widest diameter of visual field in the better eye is less than or equal to 20 degrees
Legally blind
Hemianopsia
Loss of 1/2 of the visual field
Chiasmal tumor (pituitary tumor) pressing on the optic chiasm causes
Bitemporal hemianopsia
Homonymous hemianopsia
Loss of 1/2 of the same side of the visual field in each eye
What can cause homonymous hemianopsia?
Complete loss of nerve function at the - right optic tract or a - complete right optic radiation defect (often due to stroke)
Quadrantinopsia
Blindness in 1/4 of the visual field
What causes quadrantinopsia?
Partial lesion of the optic radiation on one side - usually due to a stroke in the parietal lobe
The loss of the superior 1/4 of the left visual fields (due to injury to the inferior part of the right optic radiation)
Homonymous left superior quadrantinopsia
Normal pupillary light reflex direct response
Pupil with the light source constricts
Normal pupillary light reflex consensual response
Constriction of the pupil in the eye opposite from the light source
