cranial nerves and testing

olfactory nerve function (CN I)

sensory

smell - tied to the limbic system

testing procedure for olfactory nerve

check patency of nasal passages

test each nostril separately

present non-irritating substance

anosmia

inability to smell

optic nerve (CN II) function

sensory - vision (afferent)

testing procedure for optic nerve - visual fields

cover one eye, pt looks at PT nose

bring fingering visual field at each quadrant — pt say when they see PT finger

testing for optic nerve - visual acuity

cover one eye

distant vision - 20 ft from Suellen chart
near vision - 14 ft from pocket chart

ocular fundi

examined with ophthalmoscope

you can actually see the retina

red saturation testing

test each eye separately for ability to distinguish colors

red desaturation

sign of subtle asymmetry in optic nerve function

anopsia/anopia

absent vision

optic nerve lesion is named how

in what the pt cant see

hemi-anopsia

cannot see half of their visual field

pupillary light reflex, pupillary accommodation response controlled by

CN II and III

testing procedure for pupillary light reflex

shine light into eyes and observe direct response of the eye being tested

normal response to pupillary light reflex

pupil constriction in response to light and consensual response of the opposite side

pupillary accommodation response testing procedure

have pt look at finger - move back and forth look for convergence

normal response for pupillary accommodation response

pupil constriction, convergence of eyes while fixation on an object moving toward eyes

perla

pupils equal and responsive to light and accommodation

how are CN III, CN Ivm and CN VI connected

through information from the medial longitudinal fasciculus

oculomotor nerve (CN III) function

lifts upper eyelid - levator palpebrae
constricting pupil - iris sphincter
accommodating eye - ciliary muscle 

what muscles does CN III innervate

superior rectus

medial rectus

inferior rectus

inferior oblique 

superior rectus function

moves eye upwards

medial rectus function

move eye medially

inferior rectus function

move eye down

inferior oblique function

torsion of the eye upward

what does CN IV innervate

superior oblique

superior oblique function

torsion of eye upwards

what does CN VI innervate

lateral rectus

lateral rectus function

move eye laterally

assess extraocular movements (EOM) testing procedure

pt head stationary and follow moving finger in all planes of movement

do both eyes together

ptosis

drooping of eyelid

trigeminal nerve (CN V) function

sensory and function

CN V sensory to

face

anterior 2/3 of tongue

mouth

nasal sinuses

supratentorial dura

CN V motor to

masseter

temporalis

medial and lateral pterygoid

tensor tympani

corneal reflex 

CN V and VII

facial nerve CN VII function

motor and sensory

CN VII sensory to

taste to anterior 2/3 of the tongue

small areas of sensation 

external auditory meatus

salivary glands

lacrimal glands

CN VII motor to

muscle of facial expression

stapedius and digastric 

testing procedure for CN VII motor

test upper and lower face muscles

raise eyebrows, smile, open eyes

function of vestibulocochlear nerve (CN VIII)

sensory - hearing and vestibular

provide information to maintain posture, muscle tone, and oculomotor control in response to head movements 

rinne test

air conduction compared to bone conduction

normal: air conduction heard better

conductive hearing loss with rinne test

bone conduction is hear louder

weber test

vibrating fork placed on head

normal: vibration heard equally on both sides

if conduction hearing loss is suspected have pt:

hum - it will be louder in affected ear

if sensorineural hearing loss suspected have pt:

hum - it will be quieter on affected side

conductive hearing loss caused by

abnormalities of the external auditory canal or middle ear

ex: ear wax

sensorineural hearing loss caused by

disorders of the cochlea or CN VIII

function of CN IX (glossopharyngeal nerve)

motor and sensory

motor function of CN IX

stylopharyngeus muscle - elevate pharynx during talking/swallowing

sensory function of CN IX

taste posterior 1/3 of tongue

sensation to middle ear

auditory meatus

pharynx

testing procedure for CN IX

taste of posterior tongue

gag reflex

CN IX and CN X

function of CN X (vagus nerve)

sensory and motor

sensory function of CN X

taste from epiglottis

pharynx

meninges

small area near auditory meatus

motor function of CN X

pharyngeal muscles - swallowing

laryngeal muscles - voice

testing procedure of CN X

pt open mouth - look for symmetrical elevation of soft palate

uvula should remain in midline

deviation towards intact side

CN XI (spinal accessory nerve)

contralateral innervation

formed by union or cranial and spinal root

function of CN XI

motor to SCM and upper trap

testing procedure of CN XI

MMT of SCM and upper trap

CN XII (hypoglossal nerve)

contralateral innervation

emerge at medulla

function of CN XII

motor or intrinsic muscle of tongue

testing procedure of CN XII

protrusion of tongue

deviation to the affected side 

“lick your wounds”

nerve memonid

oh

once

one

takes

the

anatomy

final

very

good

vacations

sure are

had

function memonic

some 

say

marry

money

but

my

brother

says

big

butts

matter

more