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CN V, VII
CNpathies
Question | Answer |
---|---|
what does the CN V innervate? | muscles of mastication: temporalis, masseter, lateral/medial ptergoids other muscles: tensor tympani, veli palatini, mylohyoid, ant belly of digastric muscles |
what are the 3 exits of the CN V? | V1: superior orbital fissure V2: foramen rotundum V3: foramen ovale |
where does the CN V travel to? | go to pons, medulla or cervical spine secondary neurons go to VPM thalamus |
when sensory from the body, which thalamic nucleus does it go to? | VPL |
when sensory from face, which thalamic nucleus does it go to? | VPM |
if you lesion facial nucleus, what happens to facial sensation? | concentric rings of facial sensory loss |
how does trigeminal neuralgia act? | paroxysmal brief attacks of pain involving 1+ divisions of trigeminal n intense sharp, superficial stabbing precipitated from trigger zones |
how do you differentiate b/w classic and symptomatic trigeminal neuralgia? | classic: no d/o symptomatic: causative lesion other than vascular compression |
what are some facts about trigeminal neuralgia? | V2 most affected female >male peak age 60-70 unusual before age 40 |
what are common etiologies for trigeminal neuralgia? | MS ectopic loop meningioma bony deformity charcot-marie-tooth schwannoma AV malformation tortuous basilar primitive trigeminal a saccular aneurysm |
what's the tx for trigeminal neuralgia? | meds: carbamazepine, oxcarbazepine, baclofen, lamotrigine sx: gamma knife, microvascular decompression |
37 yo male presents w/ L face weakness and reduced taste. what tx? | prednisone only |
what muscles does CN VII innervate? | stylohyoid muscle post belly of digastric stapedius |
what's the func of the stapedius? | dampens sounds |
what portion of the tongue does CN VII handle taste for? | ant 2/3 |
what takes care of sensation of the posterior surface of the external ear and ear canal? | CN VII |
what are the parasympathetic actions of CN VII? | salivation and lacrimation |
what are the pathways of the facial n? | superior salivatory nucleu and tractus solitarius join to form the nervus intermedius the nervus intermedius joins the motor nucleus fibers in the internal auditory canal to form the geniculate ganglion then, branches come off |
what are the branches that come off of the geniculate ganglion? | greater petrosal n chorda tympani stapedius n branch to stylomastoid foramen |
what does the greater petrosal n branch to? | pterygopalatine ganglion: lacrimal gland and glands of nose, palate and sinus |
what does chorda tympani do? | lingual n: taste for ant 2/3rd tongue submandibular ganglion |
what does the branch of the CN VII innervate? | muscles of facial expression stylohyoid post belly of digastric ant/sup auricular muscle occipitalis |
what are symptoms of Bell's palsy? | pain behind ear hyperacusis facial weakness loss of taste |
what's the clinical course of Bell's palsy? | 2/3 recover spontaneously 85% improve in about 3 weeks |
what should the tx of Bell's palsy be? | NEJM (2007): prednisolone 25 mg BID no evidence of benefit w/ acyclovir Lancet (2008): prednisolone 60 mg x 5 d, 10 mg x 5. valacyclovir had no effect |
what is : repeated involuntary bilateral contractures of the orbicularis oculi muscles? | blepharospasm |
what are common causes of blepharospasm? | Meige syndrome MS MSA |
what is Meige syndrome? | idiopathic blepharospasm and oromandibular dystonia sustained grimacing around the mouth, platysma contraction and sustained neck flexion |
what is hemifacial spasm? | unilat involun hyperactive dysfunction insidious onset of painless, arrhythmic, tonic/clonic intermittent spasms |
what's the most common cause of hemifacial spasm? | lesions near cerebellopontine angle |
what happens if you have a supranuclear facial n lesion? | contralateral weakness of lower 2/3 of face |
what happens if nuclear/peripheral facial n lesion? | ipsi weakness of upper/lower face |
where is the CN VII nucleus? | pons |
hat innervation does the upper third of the face have? | bilat innervation by fibers from precentral gyrus |