CN deficits Flashcards
CN1- function
sense of smell, nerves traverse the cribiform plate and enter the olfactory placode
Only sensory nerve that doesn’t synapse in the thalamus
CN1- disorders
anosmia can be caused by fracture of the cribiform plate or tumor
what may leak if there is a fracture to the cribiform plate
CSF
CN 2- function
vision
CN2- disorders
papilledema- inc ICP or Foster Kennedy tumor
Optic neuritis
papilledema
takes along time to lose vision but atthe end vision loss is sudden and permanant
can be caused by inc ICP
Optic Neuritis
Associated with MS,
lose ventral vision but peripheral vision is fine
visual loss is sudden but most likely will recover
CN III- function
Extraoccular muscles except SO and LR
pupillary sphincter
accommodation
CNIII - pathology- appearance and causes
ptosis, pupil is fixed and dilated, down and out
caused by aneurysm of PC of IC artery, uncal herniation, or diabetic neuropathy
CN IV- fx
innervates SO
CN IV- pathology
eye is deviated up and in
pt will have have diplopia esp when they walk down stairs
caused by pontine lesion
CN V- function
muscles of mastication and heating
sense of touch and pain from face, nasal/ oral mucosa, and teeth
CN V- pathology
trigeminal neuralgia- tic doulerous- pain affects one or more of the 3 divisions of the trigeminal nerve, often triggered by touch
Treatment of CN V pathology
anticonvulsants ie phenytoin or carbamazepine
Surgery if drugs fail
CN VI- function
innervates abducens muscle- lateral gaze
CN VI- pathology
eye is deviated medially
horizontal diplopia
Causes of CN VI pathology
tumor- pontine glioma
diabetes
CN VII- function
branchiomotor for facial muscles, playsma and stapedius
taste from ant 2/3 of tongue
skin sensation from external auditory meatus and back of ear
secretory to lacrimal gland and mucous membrane of nose and mouth
CN VII- pathology
bells palsy- paralysis of U and lower facial muscles- cant close eye ultimately recover function often preceded by pain behind the ear some taste impairment tx is prednisone in 1st week
Common cause of Bells Palsy
HSV
CN VIII- function
hearing
balance
CN VIII pathology
deafness- conductive or sensorinureal
vertigo- labyrinthe dz Menieres disease. hearing loss gets worse with each attack until totally gone.
acoustic neuroma
Minieres disease
sudden attacks of vertigo (whirling sensation and nausea) with decreased hearing
How is Vertigo tx
Antihistamines can help during an attack
Acousic neuroma
benign tumor arising fro the vestibular nerve
CN IX- function
cutaneous senseation from skin behind hte hear
taste, touch, and pain from post 1/3 of tongue, post pharynx and euxtachian tube
baroreceptors from carotid sinus
CN IX- pathology
glossopharyngeal neuralgia- paroxysmal pain in throat esp when swallowing, tx with phenytoin or carbamazepime, surgery.
CN X- function
touch and pain to skin on back of ear and post wall or external auditory meatus
GVA- to pharynx, larynx, trachea, esophagus, thoracic, and abdominal viscera.
scattered taste buds and epiglottis
preganglionic fibers to terminal PNS ganglia for innervating thoracic and abdominal viscera
branchiomotor fibers to voluntary striated muscles of larynx and pharynx
CN X- pathology
pharyngeal branch injury–> dysphagia
recurrent laryngeal injury –> hoarseness
what is CN X stimulation used for
tx epilepsy
CN XI- function
joins vagus to innervate intrinsic muscles of larynx
SCM and Trap
CN XI- pathology
winging scapula
CN XII- function
skeletal muscle of the tongue
CN XII- pathology
rarely injured
unilateral injury causes fibrillation and atrophy of affected side of the tongue. Tongue protrudes toward paralyzed side
CN of forebrain
I, II
CN of midbrain
III, IV
CN of Pons
V, VI, VI, VII, VIII
CN of medulla
IX, X
