Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
60 Cards in this Set
- Front
- Back
What is the pneumonic for which cranial nerves are sensory, which are motor, and which are both?
|
Some say marry money but my brother says bad business marrying money
|
|
Most important CNs for us?
|
I-VIII
|
|
What is a fascicle?
|
The portion of the cranial nerve from the nucleus until it exits the brainstem.
|
|
What is an infranuclear disorder?
|
Any damage to a cranial nerve that is below the nucleus, either in the fascicle region or after it exits the brainstem and is a full fledged cranial nerve.
|
|
Which cranial nerves are not in the brain stem?
|
I (olfactory) and II (optic nerve)
|
|
What is unique about basal cells of CN I?
|
Basal cells in the basement membrane (epithelium) of the olfactory nerve produce new receptor cells ever 60 days. The only area in the entire CNS that regenerates cells.
|
|
What is the primary olfactory area?
|
Rhinencephalon (olfactory association area, hypothalamus, thalmus-orbitofronal cortex)
|
|
What is unique about the olfactory tract of CN I?
|
The only sensory nerve that has PRIMARY SENSORY NEURONS in the epithelium as RECEPTORS.
|
|
Problems associated with CN I
|
anosmia (difficulty smelling)
ageusia (difficulty tasting) |
|
Possible causes for CN I problems
|
Cold, allergy affects receptor
Viral cause affects receptor Trauma affects primary axon Neoplasm (tumor or aneurysm) can affect blub or tract. |
|
Symptoms of Frontal Lobe Dysfunction
|
Seizures
Mental Changes Depression or Euphoria Inappropraite language or behavior Nonfluent aphasia Confabulation |
|
Optometric Concerns with CN I
|
Optic Nerve Compression
Possible Eye Movement Anomalies Can get papilledema in one eye and optic atrophy in the other due to neoplasm in this area. Foster-Kenedy papilledema can occur because olfactory is right above the optic nerve. You would want to do a smell test, to determine if more frontal lobe problems are present. |
|
CN II
|
Optic Nerve (Visual Pathway)
|
|
Problems with CN II
|
Decreased Visual Acuity
Decreased Visual Field Afferent Pupillary Defect |
|
Use of neutral density filters for testing for APD
|
Similar to neutralizing phorias with a prism bar only you use a neutral density filter bar, put filters in front of good eye.
|
|
CN III
|
Oculomotor Nerve
|
|
What is unique about a palsy of CN III?
|
It presents as the most devastating picture of any EOM palsy.
|
|
Symptoms of CN III palsy
|
Eye won't go up, down, or in
Ptosis (brow up) Pupil dilated Often intorsion |
|
Causes of CN III palsy
|
Adults: equal distribution between, idiopathic, trauma, aneurysm, vascular, neoplasms
Kids: 50% congenital, but can be other, assume the worst and test from there. |
|
What 2 other things having to do with vision are controlled by CN III?
|
Accommodation and Convergence
|
|
Does CN III go through cavernous sinus?
|
Yes
|
|
What are the divisions of CN III and what structures do they innervate?
|
Superior Division: levator and superior rectus
Inferior Division: medial rectus, inferior rectus, inferior oblique. |
|
Where are the pupillary fibers located in CN III what is the significance?
|
Anteriorly, this means that pupil function is rarely spared when aneurysm is the cause of a sudden CN III palsy
|
|
What does aberrant regeneration mean? How does it relate to Cn III?
|
Aberrant regeneration is when nerves grow back incorrectly. Misdirection syndrome. Example, when CNIII nerve fibers are damaged and the IR fibers regrow to the levator.
|
|
What are the chemicals involved in regeneration?
|
Netrins, attractants, and repellants attract and repel growing nerves.
|
|
What should you think of first if you see lid-gaze dyskinesis (an abnormal amount of lid movement when looking left and right)?
|
Aberrant Regeneration
|
|
Causes of aberrant regeneration?
|
Congenital
Trauma Neoplasm Aneurysm SCARY- Neurologic emergency - Act quickly! |
|
How can an aneurysm damage fibers?
|
It can either put pressure on surrounding structures or it can burst and take nutrients from surrounding tissues.
|
|
What is the difference between diabetic CN III problems and compressive CN III problems?
|
Diabetics don't usually show signs of aberrant regeneration and pupils aren't involved. If you see a diabetic patient WITH aberrant regeneration and pupil invovlement it probably isn't the diabetes and you should act as if it's a neoplasm or aneurysm.
|
|
Optometric concerns with CN III
|
Efferent Anomalies
Many EOMs affected Diplopia Torsion possible |
|
CN IV
|
Trochlear Nerve
|
|
Causes of CN IV Palsy
|
Most commonly it's congenital or trauma
|
|
What happens with CN IV palsy
|
superior oblique palsy
|
|
Symptoms of CN IV palsy
|
-diplopia in down gaze an don horizontal direction
-head tilt -large vertical fusion amplitudes -history of intermittent diplopia when tired |
|
Where is the nucleus of CN IV?
|
In dorsal midbrain atop MLF, below periaqueductal gray matter at the level of the inferior colliculi.
|
|
Pathway of CN IV?
|
Fascicle travels dorsally from nucleus, a small portion is in the brainstem, it decussates in the anterior medullary vellum and controls the contralateral superior oblique.
|
|
What is unique about CN IV and what is the significance?
|
It is the longest CN and this makes it more susceptible to trauma.
|
|
In what order are cranial nerves affected by aneurysm?
|
CN III is BY FAR the MOST affected by aneurysm. Then CN IV and then CN VI.
|
|
The 2 most common causes of CN IV palsy?
|
Congenital and Trauma
|
|
One weird cause for CN IV problems?
|
Ear-Nose-Throat surgery sometimes causes damage to the trochlear pulley (nicks it)
|
|
Why would you review old photographs when you suspect a congenital CN IV palsy?
|
Because you will often see head tilt in all pictures, these people can't tell that their heads are tilted, everything looks perfectly upright.
|
|
Optometric Concerns with CN IV
|
Vertical Diplopia
Torsion Head Tilt |
|
CN V
|
Trigeminal Nerve
|
|
What kind of nerve fibers are in CN V?
|
Motor and Sensory (somatic)
|
|
Where is the motor nucleus of CN V? Where is the sensory nucleus?
|
Motor: Pons
Sensory: It's long and it extends from the pons through the medulla and into the spine. |
|
What are the divisions of the trigeminal nerve? Which divisions go through the cavernous sinus?
|
Ophthalmic*, Maxillary*, Mandibular.
*cavernous sinus |
|
Three major branches of ophthalmic division of CN V
|
Frontal Nerve: medial upper lid and medial forehead
Lacrimal Nerve: lacrimal gland, lateral upper lid, and conj Nasociliary Nerve: medial lid, side of nose, ethmoid, ciliary nerves, afferent corneal reflex |
|
How do you test the corneal reflex? Which nerve are we testing?
|
Have patient look up
Bring floss to touch lower cornea Switch ends for each eye They should blink (CN V goes back to VII nerve which causes lid to blink) |
|
What is Trigeminal Neuralgia?
|
Tic Douloureux
Severe, sharp, stabbing pain Worst possible Often triggered by specific stimuli Pain lasts less than 2 minutes |
|
Oragnization of CN V nerve receptors rostral to caudal
|
proprioception
light touch pain (deepest) |
|
Optometric concerns with CN V
|
Afferent portion of corneal blink response.
|
|
CN VI
|
Abducens Nerve
|
|
CN VI Nuclei?
|
Paired nuclei at level of pons and 4th ventricle
|
|
What are the 2 types of neurons contained in the CN VI nuclei?
|
ipsilateral to LR
contralateral through medial longitudinal fasciculus to medial rectus. |
|
What kind of palsy is most common cause of strabismus
|
CN VI
|
|
Where is CN VI most susceptible to trauma and inflammation?
|
Where is crosses the petrous bone
|
|
Optometric concerns with CN VI
|
Horizontal diplopia
Esotropia (CN VI Palsy) Common post stroke, trauma |
|
Causes of CN VI Palsy
|
Adults and Kids
Neoplasms, Trauma Idiopathic |
|
CN VII
|
Facial Nerve
|
|
What is unique about CN VII
|
It is the most frequently paralyzed
|