Anatomy - Cranial Nerves Flashcards
(54 cards)
1
Q
Three nerves for the eye
A
- Oculomotor (III)
- Trochlear (IV)
- Abducent (VI)
2
Q
Oculomotor nerve course
A
- from brainstem, in between the two pillars
- lies upon circle of willins
- to cavernous sinus (on lateral wall)
- through superior orbital fissure
- gives off motor nerves
- parasympathetic goes through ciliary ganglion
3
Q
Through which foramina does the oculomotor nerve exit?
A
Superior orbital fissure
4
Q
What ganglion does the parasympathetic part of oculomotor go through
A
Ciliary Ganglion
5
Q
What does the parasympathetic fibers of the oculomotor nerve innervate
A
- Ciliaris
- sphincter pupillae
6
Q
What do the motor fibers of the oculomotor nerve innervate
A
- Most muscles of the eye except SO and LR
- LPS
- MR
- SR
- IO
- IR
7
Q
Clinical issues with the oculomotor nerve
A
- hemmorage near circle of willis, aneurysms
- pupil dilation: mydriasis
- no pupillary reflex
- no accomodation
- lateral squint: down-out
- diplopia: double vision
- ptosis: because LPS is damaged
8
Q
Trochlear nerve course
A
- only cranial nerve that crosses to the other side in the periphery
- goes through cavernous sinus on lateral wall
- exits skull through the orbital fissure
- along the superior eyelid
9
Q
What type of fibers does the trochlear nerve have
A
- only motor
10
Q
What fissure does the trochlear nerve exit by
A
- Superior orbital fissure
11
Q
What does the trochlear nerve innervate
A
- Superior oblique
12
Q
Clinical issues for the trochlear nerve
A
- rise in intracranial pressure
- slight lateral squint (extortio) - patients may try to correct this by tilting their head to one side. This is because the inferio oblique is rising the eye and SO cant contradict it
- weak eye depression when adducted
- diplopia
13
Q
Abducent nerve course (VI)
A
- stupid
- down then hits sphenoid bone, goes back up
- goes through cavernous sinus next to internal carotid
- exits via superior orbital fissure
- innervates lateral rectus
14
Q
What fissure does the abducent nerve use to exit the skull?
A
- the superior orbital fissure
15
Q
What does the motor fibers of abducent nerve innervate?
A
- lateral rectus
16
Q
What type of fibers does the abducent nerve have?
A
- motor only
17
Q
Clinical issues with abducent nerve
A
- carotid dilation, pathology, rICP
- medial squint: esotropia: diplopia
18
Q
Two cranial nerves for the face area
A
- Trigeminal (V)
- Facial (VII)
19
Q
Trigeminal nerve three parts
A
- ophtalmic: V1
- Maxillary: V2
- Mandibular: V3
V1 and V2 are purely snesory
V3 is sensory but has a motor component
20
Q
Trigeminal nerve course
- where does the trigeminal nerve exit?
- where does it form a swelling
- Where does V1 go through?
- Where does V2 go through?
- where does V3 go through?
A
- Exit midbrain through Merkel’s cave
- forms a swelling over the petrous temporal bone and then fibers separate
- V1 through superior orbital fissure
- V2 through foramen rotundum
- V3 through foramen ovale
21
Q
What is the sensory innervztion of V1
A
- scalp
- forehead
- sinus
- eyelids
- nose
- nasal cavity
- eye
- HEAD BLOOD VESSELS
- MENINGES (particularly dura)
22
Q
What is the sensory innervation of V2
A
- upper teeth
- palate, sinus
- cheek
- upper lip
- nose
- nasal cavity
- oral cavity
- pharynx
23
Q
What is the sensory innervation of V3
A
- Lower teeth,
- tongue
- lower lip
- chin
- jaw
- ear
24
Q
What is the motor innervation of V3
A
- Mastication muscles
- TVP
- Tensor tympanic
- mylohyoid
- ant digastric
25
Clinical issues of trigeminal
- sensory face loss: neuralgia, shingles
- mastication issues: jaw deviation
- headaches: artery dilation/pathology, visceral issues, rICP
26
Facial nerve course
- where does it exit?
- where does the ganglion form
- what structures does it pass
- exits via internal acoustic meatus
- forms a swelling at facial sensory gnaglion and then first division
- second division after tympanic cavity
27
First division of facial nerve:4 courses
1) parasympathetic fiber goes above petrous temporal bone, through trigeminal ganglion. Synapse into pterygopalatine ganglion and post-ganglionic fiber go to lacrimal gland
2) motor fiber to stapediues
3) sensory fibers to ear, auricle
4) some parasympathetic and motor fibers continue
28
Second division of facial nerve
- what fissures do motor fibers and parasympathetic fibers go through?
- what is the ganglion that the parasympathetic fibers synapse to, and where do post-ganglion neurons go to?
- after the first division: goes through tympanic cavity and then further divide
- Motor fibers continue down over mastoid process through stylomastoid foramen and parotid gland
- parasympathetic fiber go through petrotympanic fissure and take advantage of chorda tympani (lingual nerves to send fibers to V3 lingual) - synapse into submandinbular ganglion and post ganglionic fibers innervate submandibular gland and sublingual gland. This is also the path for taste nerves that go to anterior 2/3 of tongue
29
What do the fibers of facial nerve innervate?
- parasympathetic
- sensory
- taste
- motor
- Parasympathetic: lacrimal gland, submandibular/sublingual gland
- Sensory: ear
- Taste: anterior 2/3 of tonghe
- motor: muscles of facial expression + stapedius, stylohyoid, post digastric
30
Clinical issues with facial nerve
- intracranial: sensory/visceral issues ( + hyperacusis), Motor (bell's palsy): middle ear infection/shingles
- extracranial: motor (Bell's palsy): Parotid tumour/infections/ mastoid trauma
31
NErve that innervates ear
- Vestibulo cochlear
32
Cochlear nerve: function
- Sensory: hearing, frequency maps
33
Cochlear nerve: Clinical issues
- abscess/tymour, internal acoustic meatus, inner ear damage
- hearing loss: Rinne and Weber test to distinguish between sensorineural and conductive
- tinnitus
34
What foramina does the vestibulocochlear nerve use to exist brainstem?
- internal acoustic meatus
35
VEstibular nerve function
- sensory
- balance
- posture: position, movement
- ocular (head eye together, stable retinal moves)
36
Clinical issues with vestibular nerve
- Posture: balance loss, unsteady (without eyes)
- ocular: no eye-head moves, nystagmus
- visceral issues: vertigo, vomit, nausea
- will always fall towards sign of lesion
37
Innervation of mouth 3 nerves
- glossopharyngeal
- vagus
- hypoglossal
38
Glossopharyngeal nerve (IX) course
- foramen to leave brainstem
- swelling
- 5 branches off
- leave brainstem through jugular foramen
- swelling at glossopharyngeal sensory ganglion
- 1st branch off: parasympathetic fiber to parotid gland and sensory fiber to middle ear
- 2nd branch off: sensory fiber to carotid body
- 3rd branch off: motor nerve to stylopharyngeus
- 4th branch off: sensory and taste to posterior 1/3 of tongue
- 5th branch: sensory to oropharynx
39
Parasympathetic fibers of glossopharyngeal
- above which bone?
- synapse to which ganglion?
- what do postganglionic fibers innervate
- go above petrous temporal bone
- synapse into otic ganglion
- post ganglionic fiber go to parotid gland
40
Sensory fibers of glossopharyngeal nerve
- oropharynx
- posterior 1/3 of tongue
- carotid body
41
Taste fibers of glossopharyngeal nerve
- posterior 1/3 of tongue
42
- Motor fibers of glossopharyngeal
- stylopharyngeus
43
CLinical issues of glossopharyngeal
- sensory-visceral issues
- no gag reflex
- rare
44
What foramina does the vagus nerve use to exit midbrain
- jugular foramen
Then form vagus sensory ganglion
45
Divisions of vagus nerve: sensory
- one to aorta/baroreceptors
- two separate fibers to vocal folds (posterior and superior)
- laryngopharynx
- thorax/ upper GIT
46
Taste fibers of vagus
- to larynx
47
- parasynmpathetic fibers of vagus
- go through carotid sheath with IJV and CCA an then synapse into thorax/abdomen ganglia
- post ganglioninc fiber innervate thorax and upper GIT
48
Motor branches of vagus nerve
- pharyngeal plexus (middle constrictor)
- muscles of palate (except TVP)
- muscles of pharync (except stylopharyngeus)
- Cricothyroideus and cricopharyngeus
- all laryngeal muscles except cricothyroideus
49
Clinical issues with vagus nerve
- sensory-visceral issues
- dysphonia: recurrent laryngeal is damaged - cant contract cricothyroideus
- dysphagia: problem swallowing because constrictors are not working
- dyspalatia; problems with palate
50
Hypoglossal nerve: course
- exit midbrain through hypoglossal canal
| - crosses carotid around the loop of lingual
51
Hypoglossal nerve: innervation
- only motor: tongue
- hyoglossus
- all glossal muscles except palatoglossus
52
Clinical issues with hypoglossal nerve
- nearly always unilateral
| - glossal palsy: ask to stick tongue out: deviation to the right (side of lesion)
53
Accessory nerve: neck nnervation
- what spinal levels
- what foramen
- what muscles
- at spinal cord level C1-6
- exit through jugular foramen
- separates into to innervate SCM and trapexius
54
Accessory nerve clinical issues
- shoulder/head movement
- viral infection?
- difficulty turning to opposite side of lesion and shrugging shoulder
