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93 Cards in this Set

  • Front
  • Back
Which nerves go through the superior orbital fissure?
Occulomotor, trochlear, opthalmic (V1) and abducent
Which nerves go through the cavernous sinus?
occulomotor and trochlear go along the lateral wall
The abducent (stupid nerve) goes right along beside the internal carotid artery
What signs are there of an occulomotor nerve palsy? (5 things)
- no LPS --> droopy eyelid = ptosis
- no sphincter --> dilated pupil = (mydriasis) also, don't get pupillary reflex contraction, but consensual response will be fine
- lateral and down squint (only have LR and SO)
- no accommodation (because the ciliaris muscle isn't working)
What is ptosis?
Droopy eyelid
What is mydriasis?
dilated pupil
Why is trochlear the 'weird nerve'?
- Subtle effects when it's damaged
- Crosses over in the periphery
- Comes from the back
What happens if you have trochlear nerve damage?
Won't have SO --> eye will be slightly extorted --> they tilt their head. Might be elevated a bit
Also, they will have problems looking down from the adducted position --> difficult going down stairs etc
Why is abducent the dumb nerve?
It goes through the cavernous sinus right next to the ICA = dangerous
And it crashes into the sphenoid - also dangerous
What happens if abducent is damaged?
Don't have the LR --> medial squint = esotropia
Where is the abducent at risk of getting damaged?
When it crashes into the sphenoid
And next to the ICA - eg if there's excessive vasodilation of the artery or if there's a pathology in the artery
Where do the three trigeminal nerves all exit the skull?
V1 - superior orbital fissure
V2 - foramen rotundum then inferior orbital fissure
V3 - foramen ovale
What nerve is sensory to the ear?
V3
What nerve is sensory to the eye?
V1
Where do all the facial nerve fibres come out of?
Where do just the motor fibres go through?
And where does the chorda tympani go through?
All - internal acoustic meatus
the motor fibres go through the stylomastoid foramen
the chorda tympani goes through the petrotympanic fissure
What are the two 'streams' of parasymp fibres from the facial nerve?
- PpG --> oral and nasal cavity kinda area and the lacrimal gland
- chorda tympani - goes down to the tongue and sub glands via the V3 nerve ie it hitches a rid
Where does the chorda tympani go?
It hitches a ride on V3 and gives parasympathetic innervation to the front 2/3 of the tongue as well as to the sub glands via the submandibular ganglion
What does a nystagmus indicate? Which side says what?
Nystagmus is sign of vestibulocochlear nerve problem
(The vestibular part of it)
The side of the beating nystagmus = side of the lesion
What two nerves are carried by V3?
Glossopharyngeal and the facial
What is glossopharyngeal nerve motor to?
Only one muscle = stylopharyngeus
What is the glossopharyngeal nerve sensory to?
The oropharynx, back of the tongue, baroreceptors in the carotid bodies and the middle ear cavity (internal part of the tympanic membrane)
What is the innervation of the tympanic membrane?
outer part = V3 and C2-3
Inner = glossopharyngeal
Where does parotid gland get its parasympathetic innervation from?
The glossopharyngeal nerve via the otic ganglion
What is the gag reflex?
Tests glossopharyngeal (sensory to the back of the throat)
and vagus (motor) and their interconnections
What does the pharyngeal branch of the vagus innervate?
Motor to pharyngeal muscles except cricopharyngeal and all the palate muscles except TVP
motor to the laryngopharynx
What does the superior laryngeal branch of vagus innervate?
- motor to the cricopharyngeus and cricothyroideus
- taste to epiglottis --> after taste
- sensory and para to mucus mems of the larynx above and including the vocal cords
What is sensory and para innervation to mucus mems of the larynx above and including the vocal cords?
Superior laryngeal branch of vagus
What does the recurrent laryngeal branch innervate?
- Motor - all larynx muscles except cricothyroideus
- sensory and para to muc mems BELOW vocal folds
What happens if there's a problem with the vagus? just focusing on H+N (probably lots of stuff elsewhere)
dysphonia and dysphagia
plus uvula sags to the good side (because of palatoglossus)
What happens if you have a hypoglossal nerve palsy?
Atrophy of tongue on that side
And if you ask them to stick out their tongue, it will deviate to the good side
Motor to tongue muscles?
Hypoglossal
except glossopharyngeus = vagus (think of it as a pharyngeal muscle)
Motor to palate muscles?
Vagus except TVP - V3
Parasympathetic innervation of naso oro and laryngo pharynx?
Naso - facial via PpG
Oro - glossopharyngeal
Laryngo - vagus
Parasympathetic to the tongue?
Facial via submandibular ganglion
Hitched a ride with V3
Taste to the tongue
Anterior 2/3 = facial (hitched a ride with V3)
and posterior = glossopharygneal
Sensory to the tongue
Anterior - V3
Posterior - glossopharyngeal
Sensory to naso, oro and laryngo pharynx?
Naso - V2
Oro - glossopharyngeal
Laryngo - vagus
Sensory to the nasal cavity and sinuses?
V1, V2 and olfactory nerve
Motor innervation to geniohyoid
C1 via hypoglossal
Motor innervation of omohyoid
C1-3
Motor innervation of muscles of mastication
V3
What are the four cranial parasymp ganglia?
PpG
Otic
Ciliary
Submandibular
What is the journey of III?
III = occulomotor
Comes out of the midbrain, travels through circle of Willis (anastomose) then through lateral wall of cavernous sinus. It enters orbit through the SOF and is motor to all the eye muscles except LR and SO and parasymp to sphincter pup and ciliaris
Where is III at particular risk of getting damaged?
When it goes through the circle of Willis - ie if there's a cerebral aneurysm etc
What does III provide parasymp innervation to?
Sphincter pupillae and ciliaris muscles
Synapse at ciliary ganglion
What innervates the sphincter pupillae
Parasymp innervation (rest)
By III = occulomotor
via ciliary ganglion
What is mydriasis
pupil dilation
what is ptosis
droopy eyelid
What happens if you have an occulomotor nerve palsy?
- Pupil dilation ie mydriasis and lose pupil reflex (consenual will be fine but the affected side won't constrict)
- no accommodation (ciliaris)
- droopy eyelid ie ptosis because no LPS
- lateral squint - down and out
What does III innervate?
MOTOR to all eye muscles except LR and SO
PARA to ciliaris and sphincter via ciliary ganglion
Damage to which nerve causes ptosis?
Ptosis = droopy eyelid ie no LPS
Due to problem with occulomotor (III)
What is the journey of trochlear nerve?
It exits brainstem from the back and crosses over in the periphery
Travels through the cavernous sinus
Goes through superior orbital fissure then travels on top of the common tendinous ring and innervates the SO
Which nerve is the "weird" one and why
Trochlear (IV)
Weird because:
1. Only cranial nerve to leave from the back (dorsal)
2. Crosses over in periphery (effects will be contralateral)
3. Problems are subtle and hard to diagnose
Problem with IV -> what will be the clinical signs?
Damage to trochlear results in subtle changes
SO normally depresses, intorts and abducts. They'll have problems looking down in the adducted position (eg stairs, reading). Eye might be slightly extorted and raised
What is the journey of VI?
Leaves the pons, heads down towards medulla then turns back around, crashes into the sphenoid bone
Then goes through cavernous sinus right next to internal carotid artery
Through SOF to the LR
Which is the "stupid" nerve?
VI ie abducent. Has a stupid course - crashes into sphenoid and then travels very close to ICA in cavernous sinus - can easily get damaged
Which nerves travle through the cavernous sinus?
III, IV - on lateral wall
VI - right near the ICA
What happens if VI is damaged?
Won't be able to look laterally ->eye is medial ie esotropia
What is esotropia?
eye is medial
Where is VI at risk of getting damaged?
- When it crashes into sphenoid and when it travels next to it it's at risk of increases in intracranial pressure
- near internal carotid - could be damaged by vasodilation or other ICA pathologies
What are the three branches of the trigeminal nerve 's names?
1 = opthalmic
2 = maxillary
3 = mandibular
What is V1 sensory to?
Top of the head + meninges and cranial arteries
Which of teh cranial nerves is involved in sensing headaches?
Trigeminal branch 1 because it's sensory to meninges and cranial arteries
What does V1 exit skull through?
Superior orbital fissure
What does V2 exit skull through?
Foramen rotundum
What does V3 exit skull through?
Foramen ovale
Which nerve is sensory to the ear?
V3
What happens if V3 is damaged?
Sensory loss in bottom half of face + ear
Problems with mastication. If you ask them to protrude jaw (pterygoids), jaw will move to the side with the lesion. masseter will be wasted as well
what is trigeminal neuralgia?
short sharp pains in V2 and 3 regions. often due to vasodilation of artery -> presses on the nerve
What do all the branches of the facial nerve pass through?
internal acoustic meatus
What does the facial nerve supply?
Motor - facial expression, stylohyoid and post body digastric
Parasymp - nasal/oral cavs, lacrimal gland, tongue and sub mandibular and sublingual glands
Sensory - ear and taste for ant 2/3 of tongue
What is parasympathetic to the tongue?
VII via submandibular
What nerve provides taste to anterior 2/3 of the tongue?
Facial
What is teh journey of teh motor fibres of VII?
All VII fibres go through the internal acoustic meatus
Then the motor fibres exit skull through the stylomastoid foramen. Travel through parotid gland to their targets (facial exprn, stylohyoid, post digastric)
What is Bell's palsy?
problem with motor branches of VII
What is VII parasympathetic to?
Useful to think of it in two groups: 1. PPG -> nasal cav and nasophar, palate and lacrimal gland
2. chorda tympani - gives its fibres to V3 which takes it to the tongue and submand/ling glands (via submand ganglion)
What does VIII travel through?
Internal acoustic meatus
What happens if VIII is damaged?
Sound issues probably
But importantly, problems with vestibular part -> vertigo, unsure on your feet, wide stance. AND eye movement isn't co-ordinated with head movement -> can't focus on target when head is moving and have beating nystagmus (beating = side of lesion)
What side does the beating nystagmus go to? What nerve is damaged?
Side of the lesion
Vestibulocochlear ie VIII
What nerves are tested by the gag reflex?
Sensory to oropharynx = glossopharyngeal
Motor = vagus
What does IX innervate?
Motor - stylopharyngeus (it's only motor innervation)
Sensory - carotid body, oropharynx, post tongue, middle ear cav and medial side of tymp mem
Para - gets a ride with V3 and goes to parotid gland via otic ganglion
Which nerves get carried by V3?
Facial and glossophar
What travels in the carotid sheath?
Common carotid artery
Internal jugular vein
Vagus nerve (not all of its branches though!)
What are the three branches of X that we should know and their innervations?
1. Pharyngeal branch - sensory to laryngophar. Motor to palate (except TVP->V3) and pharynx (except stylophar -> IX)
2. Superior laryngeal - sensory and para to mucus mem of larynx including and above vocal folds. taste - back of epiglottis, motor - cricothyroideus and cricophar
3. Recurrent laryngeal
Sensory and para to muc mems of larynx under fold. Motor to all larynx except cricothyroideus
What does recurrent laryngeal branch of X innervate?
Sensory and para to muc mems of larynx under vocal fold. Motor to all larynx except cricothyroideus
What does superior laryngeal branch of X innervate?
- sensory and para to mucus mem of larynx including and above vocal folds. taste - back of epiglottis, motor - cricothyroideus and cricophar
What does pharyngeal branch of X innervate?
sensory to laryngophar. Motor to palate (except TVP->V3) and pharynx (except stylophar -> IX)
What happens if you have damage to X?
- Dysphonia (if it's recurrent branch)
- Dysphagia ie difficulty with swallowing (mostly pharyngeal branch)
- 'Dyspalatia' ie no palatoglossus action -> uvula will sag to the good side
What is special about XI?
Not technically a cranial nerve - it comes from the spinal cord (C1-5)
What does XI innervate?
Trapezius and sternocleidomastoid
What happens if XI is damaged?
Can't shrug shoulders (traps) or turn head (SCM)
What opening / hole does XI travel through?
jugular foramen
What does XII innervate?
The tongue muscles except palatoglossus = vagus
What happens if XII is damaged?
Atrophy of the affected side of the tongue
If you poke out your tongue, it will deviate to the good side