10-30 L3 Cranial nerves Flashcards
Olfactory hallucinations
damage to the primary cortical olfactory area in the temporal lobe (masses or seizures)
Anosmia/hyposmia
Fractures of the floor of the anterior cranial fossa involving the cribriform plate
-CSF Rhinorrhea
tumors, abscesses, meniniomas: compression of olfactory bulb or tract
Anomalous trichromatism
- protanomaly
- deuteranomaly
- tritanomaly
Anomalous trichromatism: defective color vision
- protanomaly: R cones abnormal
- deuteranomaly: G cones abnormal
- Tritanomaly: B cones abnormal
Dichromatopsia
- protanopia
- deuteranopia
- tritanopia
dichromatopisa: defect in matching colors, b/c instead of 3 wavelengths you have 2.
- protanopia: R cones absent
- deuteranopia: G cones absent
- Tritanopia: B cones absent
What’s the most common form of color blindness?
Anomalous trichromatism: deuteranomaly
What is the path of the visual field from the upper half
Upper visual field–>lower retina–> loop of meyer–>lingual gyrus
Damage to the visual system can be caused by?
defects in the development (anophthalmia, cyclopia) vascular problems (diabetes, occlusion) trauma to the face or head
Anophthalmia
abscess of one or both eyes
Cyclopia
failure of the embryonic prosencephalon to properly divide the eye in to two cavities.
Papilledema
increased intracranial pressure
Glaucoma
excessive intraocular pressure
Cataract
loss of transparency of the lens
Monocular blindness
damage to the optic nerve results in the loss of input from the ipsilateral eye only
-the pt. will complain of blindness in that eye.
What happens to the visual field if the chiasm is compromised (pituitary tumor).
if the medial aspect of the chiasm is compromised decussating axons are affected leading to loss of visual input from the nasal hemiretinas in both eyes
(bitemporal hemianopsia)
What happens to the visual field if the lateral aspect of the chiasm is damaged? (e.g. lesion due to an aneurysm)
Input from the temporal retinal half of the ipsilateral eye is lost, this results in loss of the ipsilateral nasal visual field.
What happens to the visual field if a lesion of Meyer’s loop (anterior part of the temporal
results in a homonymous superior quadratic anopsia.
What happens to the visual field when damage to the optic tracts, lateral geniculate nucleus, optic radiation, or visual cortex?
results in loss of input from the contralateral visual fields of both eyes.
Any cortical lesion is going to have what distinctive feature?
Macular sparing
Cochlear or spiral ganglion consists of cells located where?
In the spiral configuration at the periphery of the modiolus.
Where does high and low freq occur in the cochlea?
high freq. (base of the cochlea)
low freq. (apex of the cochlea)
Where will a lesion resulting in deafness occur?
a lesion up to and including the cochlear nuclei will result in deafness
What happens when an interruption of the lateral lemniscus occurs?
decreased ability to localize sound
Name the different types of conductive hearing loss (4-DODO)
Damage to the tympanic membrane
Occlusion of the auditory canal (cerumen impaction)
Disruption of the operation of the ossicular chain
Otitis media
Cerumen impaction
wax in the ear
Otitis media
an inflammation of the middle ear cleft
Disruption of the operation of the ossicular chain (FOD)
- Fluid accumulation (Otitis media)
- Otosclerosis
- Disarticulation
Name the different types of sensorineural hearing loss (2-DP)
- Disorders affecting the cochlea
- Problems in the transmission of information along the auditory pathways.
Disorders affecting the cochlea (4- HOMP)
- Hydrops
- Ototoxis agents
- Meniere’s disease (fluid build up in the modiluosu)
- Presbycusis (getting old)
Problems in transmission of information along the auditory pathways
lesions to cranial n VIII
Review slide
What are the 3 tracks leaving the vestibular nuclei (counter rotation of the eye).
- abducens nucleus (6) opposite
- oculomotor nucleus (3) same
- abducens nucleus same side to go to (oculomotor nucleus opp, and LR same)
Damage to the vestibular apparatus causes what?
- dizziness, falling to the side of the lesion, abnormal eye movements
- Benign paroxysmal vertigo (BPV)
Acoustic neuroma (schwannoma)
Facial n component
weakness of muscles of facial expression
lost of taste (anterior 2/3 of the tongue)
Lack of stimulation of salivary, mucosal and lacrimal glands on affected side (7th n)
Acoustic neuroma (schwannoma)
Vestibular component
dizziness, nausea, disorder of balance
Acoustic neuroma (schwannoma)
cochlear component
tinnitus, ipsilateral deafness
Meinere’s disease (SAUL)
- Severe vertigo, vomiting, ataxia
- Auditory and vestibular symptoms
- Unilateral deafness and tinnitus
- Lesion affecting the production of the endolymph
Motion sickness (Kinetosis)
- occurs when there is discrepancy between vestibular and visual inputs
- Symptoms include dizziness, vomiting, sweating
Acute alcohol intoxication
Alcohol infiltrates the cupulae
results in illusions of movement in response to certain orientations of the head.
Which of the CN are SA?
CN II, III, VII (2/3 anterior taste), VIII (balance, hearing), IX (taste around the epiglottis)
