ANATOMY - cranial nerves Flashcards
what does the PNS consist of
12 pairs of cranial nerves
31 pairs of spinal nerves
autonomic nerves - sympathetic and parasympathetic
where does CNS change to PNS
rootlets of nerves from spinal cord (before they become spinal nerves etc)
differentials of a problem with someones smell (3)
CNI injury
epilepsy
frontal lobe tumour (olfactory tract is below frontal lobe)
CNI name
olfactory nerve
CNI function
smell
CNI modality
sensory
CNI test
cover 1 nostril and test strong smells
CNI brain connection
cerebellum - temporal lobe olfactory areas
CNI cranial foraminae
cribiform plate of ethmoid bone
which lobe does CNI travel inferior to
hence … lobe tumour may affect smell
frontal lobe
what structure is in between the olfactory receptor cells and the olfactory tract
is the nerve PNS or CNS in this location
olfactory bulb
PNS, become CNS in the olfactory tract
CNII name
optic nerve
CNII function
sight
CNII tests (5)
Snellen chart visual fields ishihara chart (for colour blindness) light reflexes fundoscopy
CNII brain connection
cerebellum - occipital lobe
CNII cranial foraminae
optic canal
what surrounds the optic nerve and what is the significance of this
meninges and CSF (= optic sheath)
increased intracranial pressure = travels along optic sheath = papilloedema
which nerve may be affected by increased ICP
optic nerve
is CNII optic nerve CNS or PNS
CNS because encased in meninges
what type of tumours are significant for CNII and why
pituitary tumours
optic chiasm is directly above the pituitary
after the optic tract where do the APs synapse
lateral geniculate nucleus (LGN) of the thalamus
after synapsing at the LGN (lateral geniculate nucleus) of the thalamus, where do APs go
note: think of what signals go to LATERAL nucleus
occipital lobe
what type of APs synapse at the lateral geniculate nucleus (LGN) of the thalamus
visual
what type of APs synapse at the medial geniculate nucleus (MGN) of the thalamus
auditory
within the occipital lobe, where do APs form optic nerve go
primary visual cortex
what is the sulcus (in the occipital lobe) called in which 2 gyri (above and below) received visual information
calcarine sulcus
where do APs from the right upper visual field go (within the occipital lobe)
left occipital lobe
gyrus inferior to calcarine sulcus
remember: everything is opposites (R and L, sup and inf)
on the gyri above/below the calcarine sulcus, where does the fovea/macula send its info to (posterior or anterior)
posterior edge
what is meyers loop
‘loops’ the SUPERIOR visual field info from the lateral geniculate nucleus to the sulcus inferior to the calcarine gyrus in the occipital lobe
what visual field defect is the result of pituitary tumour
bitemporal hemianopia
what visual field defect is the result of L optic nerve (in front of chiasm) injury
L monocular blindness
what visual field defect is the result of R optic tract (behind optic chiasm) injury
L homonymous hemianopia
if a visual field defect has macula sparing, where is the problem
primary visual cortex (in occipital lobe)
CNIII name
oculomotor
CNIII function (specific)
eye movement - inferior oblique, inferior rectus, medial rectus, superior rectus (NOT lateral rectus or superior oblique bc of SO4 LR6 AO3)
levator palpebrae superioris
CNIII modality
motor
CNIII connection to brain
midbrain
CNIII cranial formainae
superior orbital fissure (SOF)
goes through with CN IV, CNV1 and CN VI too (all the extraocular eye muscles)
CNIII test
‘H’ eye movements
what is the mnemonic for remembering the nerves supply extraocular eye muscles
SO4 LR6 AO3
what does the superior branch of CNIII supply (3)
superior rectus
levator palpebrae superioris
ie - the 2 superior things!
plus PS to sphincter papillae and ciliary muscles
what does the inferior branch of CNIII supply (3)
inferior rectus
inferior oblique
medial rectus
what does CNIII palsy look like
down and out eyeball (only superior oblique and lateral rectus are working)
CNIV name
trochlear
CNIV function
eye movements - superior oblique, pulls eye down (and in)
CNIV modality
motor
CNIV test
‘H’ eye movements
CNIV brain connection
midbrain
dorsum of brain stem (diff from the others as all anterior)
CN IV cranial formainae
superior orbital fissure (SOF)
along with CN III, CNV1 and CNVI
how might someone with CN IV palsy present
head tilt - to compensate
which CN arises form the dorsum(back) of the brainstem
CN IV
which CN has the longest course, croses over etc = easily broken
CN IV
CNV name
trigeminal
div1 - ophthalmic
div2 - maxillary
div3 - mandibular
CNV function
sensory to face
motor- muscles of mastication
CNV modality
both sensory and motor
CNV brain connection
pons
CNV cranial foraminae
CNV1 - superior orbital fissure (SOF)
CNV2 - foramen rotundum
CNV3 - foramen ovale
CN V1 function
sensory - face above eyelids and bridge of nose, superior nasal cavity, cornea
CNV2 function
sensory - face between eyelids and crease of lips, ala of nose, maxillary teeth, inferior nasal cavity
CNV3 function
sensory - face between crease of lips and jaw line (under jaw line and angle of mandible = great auricular nerve C2, 3), anterior 2/3 of tongue, mandibular teeth
motor - muscles of mastication (massester, temporalis, medial pterygoid, lateral pterygoid), tensor veli palatine, tensor tympani
what is the sensory supply to the nasal cavity
V1-superior and anterior
V2-inferior and posterior
what nerve gives sensory spply to angle of mandible
C2,3
which nerve gives sensory supply to anterior 2/3 of tongue
CNV2
what is the nasociliary branch a branch of
CNv1
what is the significance of the nsociliary branch of V1 in singles
shingles can present with hutchisons sign (rash on tip of nose) THEN eye problems (corneal supply of V1)
what notch odes CNV2 travel through that means it is susceptible to trauma damage
infraorbital notch
which foramen is somatic sensory only
foramen rotundum
which part of the face has dual nerve supply
forehead
if there is an upper motor neurone (UMN) lesion in the nerves supplying the face, what will this present as
unilateral sensory loss but forehead sparing (as the forehead has a dual nerve supply so if one is cut off, there is still the nerve from the other side of the brain supplying it = not symptomatic)
if there is a lower motor neurone (LMN) lesion in the nerves supplying the face, how will this present
unilateral sensory loss INCLUDING the forehead (as even though the forehead has a dual nerve supply, in a LMN both nerves that supply the same sid of the forehead have met and hence there will be no sensation in that side of the forehead)
CNVI name
abducens
CNVI function
eye movements - lateral rectus (LR6)
CNVI modality
motor
CNVI test
‘H’ eye movements
CNV test
touch 6 areas of face (V1, V2, V3 bilaterally) with cotton wool, pin and tuning fork (for temp/vibration)
get them to open and close jaw with your hand on temporalis muscle (over temporal bone)
get them to open jaw with your hand underneath to give resistance (testing lateral pterygoid)
CNVI brain connection
pons-medulla junction (most medial, CNVII and CNVIII come off here too)
CNVI cranial foraminae
superior orbital fissure (SOF)
along with CNIII, CNIV and CNV1
which nerves pass through the cavernous sinus
CNIII, CNIV, CNIV, CNV1 and CNV2
which CN comes off the ponto-medullary junction most medially
which others come off here
CNVI
CNVII
CNVIII
which part of the temporal bone does CNVI (abducens) travel over
petrous part
CNVI palsy presentation
horizontal diplopia
CNVII name
facial
CNVII function
motor - muscle of facial expression, stapes bone in ear
chorda tympani branch - PS to sublingual and submandibular salivary glands
CNVII modality
both - sensory and motor
CNVII test
puff out cheeks
close eyes tightly
smile
which CN is closely associated with CNVII
comes off same place in brain and goes through same cranial foraminae
CNVIII (vestibulocochlear)
both come of ponto-medullary junction
both go through the internal acoustic meatus
which cavity does CNVII pass behind (and give off 1 branch to)
ear cavity
gives off a branch to supply to stapes bone
after going through the internal acoutics meatus and passing behind the ear cavity (in the facial canal), which foramen does the facial nerve (CNVII) go through
stylomastoid foramen
what are the 5 terminal branches of CNVII (after its given off branch to stape and chorda tympani branch)
what do they do
temporal zygomatic buccal mandibular cervical
pneumonic - two zannibar buy motor car
supply muscles of facial expression
muscles of facial expression (4)
frontalis (on forehead)
orbicularis occuli (around eyes)
orbicularis oris (around mouth)
elevators of lips
which condition affects CN VII
bells palsy
what cant someone with bells palsy do
puff out cheeks, close eyes tightly, smile etc
CNVII palsy
which salivary gland is not supplied by chorda tympani branch of CNVII (though the nerve passes over it)
parotid gland
which glands does chorda tympani branch of CNVII supply
sublingual and submandibular salivary glands
which branch of CNVII passes over the tympanic membrane
what is the clinical significance of this
chorda TYMPANI
damage to tympanic membrane = may result in loss of taste/salivation
CNVIII name
vestibulocochlear nerve
CNVIII function
vestibular branch - balance
cochlear branch - hearing
CNVIII test
rinnes and weber
CNVIII cranial foraminae
internal acoustic meatus
CNVIII brain connection
ponto-meduallry junction (with CNVI and CN VII)
what are the 2 branches of CNVIII
cochlear
vestibular
where does the info that travels in the vestibular branch of CNVIII arise
semi circular canals (anterior, posterior and lateral)
CNIX name
glossopharyngeal nerve
CNIX modality
both - sensory and motor
CNIX brain connection
medulla
CNIX function
sensory - pos 1/3 tongue, pharynx,
motor - stylopharyngeus
CNIX brain connection
medulla (medial to CNX)
which nerve supplies sensory to posterior 1/3 of tongue
CNIX glossopharyngeal
CNIX test
gag reflex
which nerve supplies eustachian tube and middle ear cavity (think about anatomy of eustachian tube)
CNIX glossopharyngeal
bc eustachian tube connects middle ear cavity to pharynx
which nerve is significant in referred pain between throat and ear
CNIX glossopharyngeal
bc of connection between 2 cavities via eustachian tube
CN X name
vagus
CNX function
supplies lots of things between palate and midgut
CNX cranial foraminae
jugular foramen
CNX modality
both sensory and motor
CNX test
say ‘ahhhhh’
swallow sip of water
hoarse voice?
cough
within which sheath does the vagus nerve run
in relation to the other things in sheath, where does it run
carotid sheath
posterior to common carotid artery and internal jugular vein
how do you differentiate between the vagus nerve CN X and the cervical ganglia in the carotid sheath
cervical ganglia have bulges
what is the first branch of the vagus nerve
what do they supply
superior laryngeal nerves
larynx cricothyroid muscles (all other larynx muscles supplied by inferior laryngeal)
what does the superior laryngeal nerve split into
internal and external superior laryngeal nerves
what is the first branch of the vagus nerve
what does it supply
superior laryngeal nerves
larynx cricothyroid muscles (all other larynx muscles supplied by inferior laryngeal)
what does the internal superior laryngeal nerve supply
mucosa above the vocal cords (bc mucosa is INTERNAL)
what does the external superior laryngeal nerve supply
cricothyroid muscles of larynx (bc muscles are EXTERNAL)
what does the inferior laryngeal nerve supply
all laryngeal muscles apart from the cricothyroid eg vocal cord muscles! important clinically
mucosa below the vocal cords
what is the anastomosis between the inferior laryngeal nerve and the internal superior laryngeal nerve called
galens anastomosis
where does the right vagus travel after being right to the oesophagus
posterior to oesophagus
laRP
where does the left vagus travel after being left to the oeosphagus
anterior to the oesophagus
LArp
where does the right recurrent laryngeal branch of the vagus go under
subclavian artery
where does the left recurrent laryngeal branch of the vagus go under
arch of aorta
what does the recurrent laryngeal branch of the vagus turn into
inferior laryngeal nerve (supplies half of larynx alongside the superior laryngeal nerve)
how does recurrent laryngeal nerve damage present
change in/loss of voice (bc they control the vocal cords)
hoarseness if unilateral
aphonia if bilateral
CNXI name
spinal accessory nerve
CNXI modality
motor
CNXI function
trapezius and sternocleidomastoid muscles
CNXI test (2)
shrug shoulders
rotate head
CNXI cranial foraminae
jugular foramen
CNXI brain connection
spinal cord
what is the route of the spinal accessory nerve
arises from cervical spine
enters cranial cavity via foramen magnum
exits cranial cavity via jugular foramen
CNXII name
hypoglossal
CNXII modality
motor
CNXII function
extrinsic and intrinsic tongue muscles (apart from palatoglossus)
CNXII test
stick out tongue
say ‘ahhh’
CNXII cranial foraminae
hypoglossal canal
which nerve supplies palatoglossus (diff form other tongue muscles)
CNX vagus
which nerve supplies palatoglossus (diff form other tongue muscles)
CNX vagus
pneumonic for names of cranial nerves in order
oh oh oh to touch and feel virgin girls vagina and hymen
pneumonic for modality of cranial nerves in order
some say money matters but my brother says big boobs matter most
