3. Cranial Nerves 1/ Introduction, Overview; Eye Movements and Autonomics Flashcards Preview

MD4001 Week 2 > 3. Cranial Nerves 1/ Introduction, Overview; Eye Movements and Autonomics > Flashcards

Flashcards in 3. Cranial Nerves 1/ Introduction, Overview; Eye Movements and Autonomics Deck (53):
1

What are the 4 modalities contained in the spinal cord and the brain stem?

Somatic
Visceral
Afferent (Sensory)
Efferent (Motor)

2

What is the order of the nerve cell bodies in the spinal cord, from dorsal to ventral?

[Dorsal]
Somatic sensory
Visceral sensory
Visceral motor
Somatic motor
[Ventral]

3

What is the order of the clustered nuclei in the brain stem from lateral to medial?

[Lateral along alar plate]
Somatic sensory
Visceral sensory
Visceral motor (PS)
Somatic motor
[Medial along basal plate]

4

Where do the cranial nerves arise from mainly?

12 cranial nerves (I to XII) arise from clusters of cell bodies (nuclei) & emerge (mainly) from the brainstem (there are exceptions!) to pass through skull fissures or foramina & supply (mainly) structures in the head & neck

Exception: Structures derived from the pharyngeal (branchial) arches & therefore ‘special’ nuclei/modalities must be added!

5

What structure seperates the efferent and afferent nuclei in the brainstem?

Sulcus limitans

6

How many brainstem modalities are there in total? Name them

(Most lateral)
1. Special somatic afferent
2. Somatic
3. Special visceral afferent
4. General visceral afferent
---- Sulcus limitans ----
5. General visceral efferent
6. Special visceral efferent
7. Somatic efferent
(medial)

7

Where does the special visceral effect modalities supply?

Muscles derived from pharyngeal arches (muscles of mastication, face, pharynx, larynx)

8

Role of the special visceral afferent modality?

Olfaction and gustation (i.e. tasting)

9

What is the role of the special somatic afferent modadlity?

Vision
Hearing
Balance

10

Generally what is the different between where CN I+II arise from compared to the rest?

Cranial nerves I & II are proximal to the brainstem, but III to XII arise more or less in sequence from the midbrain to the medulla oblongata (superior spinal cord)

11

Where do the nuclei of CN III lie in the brainstem with relation to it's modality?

Edinger-westphal: In general visceral efferent

Occulomotor: In General somatic efferent

12

Where do the nuclei of CN IV lie in the brainstem with relation to it's modality?

Trochlear: In the general somatic efferent

13

Where do the nuclei of CN V lie in the brainstem with relation to it's modality?

Mesencephalic nuclei of V: In general somatic afferent

Chief sensory nuclei of V: In General somatic afferent

Spinal nuclei of V: In general somatic afferent

14

Where do the nuclei of CN VI lie in the brainstem with relation to it's modality?

Abducens: in General somatic efferent

15

Where do the nuclei of CN VII lie in the brainstem with relation to it's modality?

Solitarius: In Special visceral afferernt

Superior salivatory: General visceral efferent

16

Where do the nuclei of CN VIII lie in the brainstem with relation to it's modality?

Vesibular cochlear: In special somatic afferent

17

Where do the nuclei of CN IX lie in the brainstem with relation to it's modality?

Spinal nuclei of V: In general somatic afferent

Solitarius: In special visceral afferent

Solitarius: In general visceral afferent

Inferior salivatory: In general visceral efferent

Ambiguus: In special visceral efferent

18

Where do the nuclei of CN X lie in the brainstem with relation to it's modality?

Spinal nuclei of V: In general somatic afferent

Solitarius: In special visceral afferent

Solitarius: In general visceral afferent

Dorsal motor nucleus of vagus: In general visceral efferent

Ambiguus: In special visceral efferent

19

Where do the nuclei of CN XI lie in the brainstem with relation to it's modality?

Spinal accessory: In special visceral efferent

20

Where do the nuclei of CN XII lie in the brainstem with relation to it's modality?

Hypoglossal: In general somatic efferent

21

Main function of CN I (olfactory)?

Sense of smell/olfaction

22

Main function of CNII (optic)?

Sense of sight/vision

23

Main function of CN III (oculomotor)?

Motor to eye movement

24

Main function of CN IV (trochlear)?

Motor to eye movements

25

Main function of CN V (trigeminal)?

Sensation of head and cavities
Motor of muscles of mastication

26

Main function of the CN VI (abducens)?

motor to eye movements

27

Main function of the CN VII (facial and nervus intermedius)?

Motor to muscles of facial expression

28

Main function of the CN VIII Vestibulocochlear?

Hearing & Balance (special somatic afferent)

29

Main function of the CNIX Glossopharyngeal?

General Sensation: (Posterior 1/3) Tongue & Oropharynx (general somatic afferent)

30

Main function of the CN X Vagus?

General Sensation: Pharynx & Larynx (general somatic afferent) Parasympathetic Heart, Lungs, GI Tract (general visceral efferent)

31

Main function of the CN XI (Spinal) Accessory?

Motor: Sternocleidomastoid & Trapezius (special visceral efferent/general somatic efferent)

32

Main function of the CN XII Hypoglossal?

Motor: Tongue (general somatic efferent)

33

Which cranial nerves pass through the following foramina:
Cribriform plate foramina Optic canal
Superior orbital fissure Foramen rotundum
Foramen ovale
Superior orbital fissure Internal acoustic meatus
Jugular foramen
Hypoglossal canal

Cribriform plate foramina: CN I
Optic canal: CN II
Superior orbital fissure: CN III, IV, V
Foramen rotundum: V
Foramen ovale: V
Superior orbital fissure: CN VI
Internal acoustic meatus: CN VII, VIII
Jugular foramen: IX, X, XI
Hypoglossal canal: XII

34

Which cranial nerves are the somatic motor nerves to the eye muscles?

III Oculomotor
IV Trochlear
VI Abducens

35

What eye muscles are supplied by the oculomotor CN III?

Muscles:
Superior rectus
Inferior rectus
Medial rectus
Inferior oblique
Levator palpebrae superioris

36

What eye muscle is supplied by the trochlear CN IV?

Superior oblique muscle (turns eye downwards and laterally)

37

What eye muscle is supplied by the abducens CN VI?

Lateral rectus (abducts the eye)

38

How are the CN III, IV and VI at risked during raising intracranial pressure?

CN III (oculomotor): is immediately ADJACENT to the TENTORIUM CEREBELLI & hence will be compressed in raised intracranial pressure

CN IV (trochlear) enters at the EDGE of the TENTORIUM CEREBELLI & may be vulnerable in raised intracranial pressure

CN VI (abducens): passes UPWARDS on the CLIVUS & may be stretched in raised intracranial pressure

39

What are the arterial relationships of the CN III?
RISK?

Oculomotor
Between posterior and superior cerebral then lies close to the posterior communicating artery

NOTE: Risk of compression during aneurysm

40

What happens to the CN III, IV & VI in Cavernous Sinus?

CN III, IV & VI pass anteriorly in the CAVERNOUS SINUS or its wall to enter the orbit through the SUP ORBITAL FISSURE
The nerves are passing close to the sympathetic fibres forming the plexus on the internal carotid artery & may pick up sympathetic fibres

41

Between which two structures does the superior orbital fissure lie?

The greater and lesser wing of the sphenoid bone

42

CN III innervation?

Muscles:
Superior rectus
Inferior rectus
Medial rectus
Inferior oblique
Levator palpebrae superioris

Parasympathetics from the edinger-westphal nucleus

Sympathetics from the
carotid plexus to supply the smooth muscle component of levator palpebrae superioris (also termed as the superior tarsal muscle)

43

CN III palsy presentation?

CN III palsy leaves the superior oblique & lateral rectus unopposed to turn the eye downwards & outwards along with ptosis (drooping of superior eyelid)

44

What are the sympathetic hitchhikers in the visceromotor control of the eye?

Sympathetic
• Smooth muscle component of levator palpebrae superioris (i.e. superior tarsal muscle)
• Pupil dilatation (via the dilator pupillae muscle innervated by long ciliary nerve

NOTE: The long ciliary nerve is a branch of the nasociliary nerve which is a branch of the ophthalamic. So...
ophthalamic --> Nasociliary --> long ciliary

45

What are the parasympathetic hitchhikers in the visceromotor control of the eye?

Synapse in the peripherally placed ciliary ganglion. Controls...
• Pupil constriction (by sphincter pupillae muscle due to short ciliary nerve)
• Lens accommodation (by ciliary muscle due to short ciliary nerve)

46

What is the parasympathetic and sympathetic input to the ciliary ganglion?

PS: From edinger-westphal nucleus via CN III.
Symp: From carotid plexus


NOTE: Parasympathetics synapse & sympathetics only pass through!

47

The sympathetics in the oculomotor nerve (CN III) supply the smooth muscle of _____ _______ _______ (superior tarsal muscle)

The sympathetics in the oculomotor nerve (CN III) supply the smooth muscle of levator palpebrae superioris (superior tarsal muscle)

48

Which sympathetics dilate the pupil?

The sympathetics in the nasociliary & long ciliary nerve dilate the pupil (dilator pupillae)

49

As the ophthalmic division (CN V1) of the _____ nerve (CN V) passes the cavernous _____, it gives off the nasociliary nerve

As the ophthalmic division (CN V1) of the trigeminal nerve (CN V) passes the cavernous sinus, it gives off the nasociliary nerve

50

What is the consequence of injury to the sympathetic trunk to the eye and face?

Injury to the sympathetic trunk (such as tumour at the apex of the lung) will remove the sympathetic supply to the pupil dilator, the smooth muscle of levator palpebrae superioris, the sweat glands & blood vessels of the face on the same side.

Name: Horner’s Syndrome
Presentation: Miosis, Ptosis, Anhydrosis, Flushed face

51

Visceromotor: Parasympathetic
Preganglionic parasympathetic fibres running in the ______ nerve (CN III) that synapse in the ciliary _____.
Postganglionic fibres that pass in the short _____ nerve to the pupil constrictor (sphincter _____) & the ciliary muscle for lens accommodation

Visceromotor: Parasympathetic
Preganglionic parasympathetic fibres running in the oculomotor nerve (CN III) that synapse in the ciliary ganglion

Postganglionic fibres that pass in the short ciliary nerve to the pupil constrictor (sphincter pupillae) & the ciliary muscle for lens accommodation

52

Injury to the oculomotor nerve (CN III) will remove the ________ pupil constriction leading to a dilated pupil with ptosis (complete loss of levator palpebrae superioris) & the eye is turned downwards & outwards (superior _____ & _____ rectus)

Injury to the oculomotor nerve (CN III) will remove the parasympathetic pupil constriction leading to a dilated pupil with ptosis (complete loss of levator palpebrae superioris) & the eye is turned downwards & outwards (superior oblique & lateral rectus)

53

How does the PS control of the lacrimal gland differ from the other structures supplied?

In the orbit the lacrimal gland is under the control of the parasympathetic system but derived from the FACIAL NERVE (CN VII)