Head and Neck Session 8 Flashcards Preview

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Flashcards in Head and Neck Session 8 Deck (38):
1

Overview of fibres carried by CN III- oculomotor nerve>

somatic fibres to extrocular muscles- medial rectus, superior rectus, inferior rectus, inferior oblique, autonomic fibres to pupil of eye- sphincter pupillae and ciliary muscles- accomodation of lens, and autonomic fibres to eyelid- levator palpebrae superioris

2

how is trigeminal nerve assessed?

corneal reflex
testing sensory division
testing motor division

3

which nerves must be funcitoning for corneal reflex?

trigmeinal- sensory limb, opthalmic division and facial- motor limb- orbicularis oculi

4

when testing motor component of trigeminal nerve- muscles of mastication, what will unilateral wkness causes when patient bites down or clenches their teeth?

jaw deviates towards side of lesion

5

3 fissures of cranial base that trigeminal nerve branches emerge through?

superior orbital fissure= opthalmic
foramen rotundum= maxillary
foramen ovale= mandibular

6

how is taste conveyed from anterior 2/3 of tongue?

via facial nerve fibres which joint with chorda tympani

7

how to distinguish between stroke and bell's palsy?

bell's= all muscles of facial expression impaired
stroke= forehead sparing= occipitofrontalis and orbicularis oculi, due to their bilateral innervation

8

what is the anatomical oculomotor nerve proper?

pure somatic efferent nerve to all extraocular muscles apart from sup oblique and lateral rectus, and to levator palpebrae superioris

9

what happens with a complete palsy of oculomotor nerve proper?

present with down and out position of eye due to paralysis of all extraocular muscles aside from sup oblique which moves eye down, and lateral rectus which moves eye out
drooping (ptosis) of upper eyelid due to LPS paralysis

10

why might patient with oculomotor nerve palsy present with a dilated pupil?

loss of PNS innervation to sphincter pupillae, and unopposed action of dilator pupillae innervated by intact sympathetic fibres.
PNS fibres actually hitch hike onto nerve, so likely to be damaged if nerve damaged, but actually originate from Edinger-Westphal nucleus whereas oculomotor nerve proper from oculomotor nucleus

11

origin of oculomotor nerve proper?

oculomotor nucleus in midbrain

12

oculomotor nerve site of exit from cranium?

superior orbital fissure

13

2 branches of extracranial portion of oculomotor nerve proper

dorsal and ventral

14

muscles supplied by dorsal branch of oculomotor nerve proper?

superior rectus
levator palpebrae superioris

15

muscles supplied by ventral branch of oculomotor nerve proper?

medial rectus
inferior rectus
inferior oblique

16

why is the presentation of a patient with a dilated pupil, in addition to a down and out eye and ptosis more worrying than if pupil wasn't dilated?

more likely that damage to oculomotor nerve is result of compression by an aneurysm of tumour

17

within which artery might an aneurysm occur to cause a complete palsy of the oculomotor nerve?

posterior communicating artery

18

what might be the cause of damage to the autonomic nerve fibres from the Edinger-Westphal nucleus, but sparing anatomical oculomotor nerve, causing a dilated pupil and loss of accomodation reflex?

bacterial or viral infection

19

presentation of a patient with damage only to PNS portion of oculomotor nerve?

dilated pupil- sphincter pupillae
loss of accomodation reflex- ciliary muscles
normal oculomotion- MR, SR, IR and IO intact
normal palpebral fissure- LPS intact

20

what is the usual cause of damage to only the somatic portion of the oculomotor nerve?

poor blood supply e.g. diabetes or increased BP

21

why are PNS fibres of oculomotor nerve susceptible to compression by an anuerysm of tumour?

fibres are relatively superficial

22

when does bilateral damage of facial nerve occur?

Parkinson's disease
SE of certain medications e.g. anti-psychotics

23

when is the facial nerve at risk of damage?

forceps delivery
parotidectomy
parotitis
partoid tumour
tympanectomy
nerve inflammation within facial canal
surgical procedures of infratemporal fossa
nerve incision

24

what nucleus do special sensory fibres for taste of facial nerve terminate in?

nucleus solitarius in medulla

25

what fibres does the chorda tympani, part of facial nerve, transmit?

special sensory to join lingual nerve to convey taste
pre-synaptic PNS fibres to submandibular ganaglion to supply SM and SL glands

26

how does the greater petrosal nerve, given off in the facial canal, contribute to PNS innervation?

carries pre-ganglionic fibres to pterygopalatine ganglion

27

where does facial nerve proper originate?

facial motor nucleus in pons

28

PNS fibres of facial nerve come from which nucleus?

superior salivatory

29

general sensory fibres of facial nerve are from which ganglion?

geniculate

30

what is innervation provided to by somatic sensory fibres of facial nerve?

small area of skin of concha of auricle

31

why would a parotid tumour cause a facial nerve motor palsy?

congestion would occur within tight parotid sheath which doesn't allow expansion if increased pressure and so the nerve would be compressed

32

3 PNS ganglia assoc with trigeminal nerve?

otic ganglion- glossopharyngeal, via auriculotemoral
submandibular ganglion- facial, via lingual
pterygopalatine ganglion- facial, via maxillary branch of trigeminal

33

the maxillary branch of the trigeminal is associated with which PNS ganglion?

pterygopalatine, to lacrimal, nasal and palate glands

34

occipitofrontalis and the superior part of orbicularis oculi are supplied by which branch of facial nerve?

temporal

35

which branch of facial nerve supplies inferior part of orbicularis oculi?

zygomatic

36

which branch of facial nerve supplies buccinator, orbicularis oris and zygomaticus?

buccal

37

which branch of facial nerve supplies mentalis?

marginal mandibular

38

which branch of facial nerve supplies platysma?

cervical