Cranial nerves Flashcards
1
Q
CN nerve modalities - olfactory nerve - CN I
A
Special sensory
2
Q
CN nerve modalities - optic nerve - CN II
A
Special sensory
3
Q
CN nerve modalities - oculomotor nerve - CN III
A
somatic motor and parasympathetic
4
Q
CN nerve modalities - trochlear nerve - CN IV
A
somatic motor
5
Q
CN nerve modalities - trigeminal nerve - CN V1, CN V2, CN V3
A
CN V1 - sensory
CN V2 - sensory
CN V3 - sensory and motor
6
Q
CN nerve modalities - abducens nerve - CN VI
A
somatic motor
7
Q
CN nerve modalities - facial nerve - CN VII
A
special sensory
somatic sensory
somatic motor
parasympathetic
8
Q
CN nerve modalities - vestibulocochlear nerve - CN VIII
A
special sensory
9
Q
CN nerve modalities - glossopharyngeal nerve - CN IX
A
special sensory
somatic sensory
visceral sensory
somatic motor
parasympathetic
10
Q
CN nerve modalities - vagus nerve - CN X
A
somatic sensory
special sensory
visceral sensory
somatic motor
parasympathetic
11
Q
CN nerve modalities - spinal accessory nerve - CN XI
A
somatic motor
12
Q
CN nerve modalities - hypoglossal nerve - CN XII
A
somatic motor
13
Q
What foramen does CN I pass through?
A
Cribriform plate of the ethmoid bone
14
Q
What foramen does CN II pass through?
A
Optic canal
15
Q
What foramen does CN III pass through?
A
Superior orbital fissure
16
Q
What foramen does CN IV pass through?
A
Superior orbital fissure
17
Q
What foramen does CN V1 pass through?
A
Superior orbital fissure
18
Q
What foramen does CN V2 pass through?
A
Foramen rotundum
19
Q
What foramen does CN V3 pass through?
A
Foramen ovale
20
Q
What foramen does CN VI pass through?
A
Superior orbital fissure
21
Q
What foramen does CN VII pass through?
A
Internal acoustic meatus
22
Q
What foramen does CN VIII pass through?
A
Internal acoustic meatus
23
Q
What foramen does CN IX pass through?
A
Jugular foramen
24
Q
What foramen does CN X pass through?
A
Jugular foramen
25
What foramen does CN XI pass through?
Jugular foramen
26
What foramen does CN XII pass through?
Hypoglossal canal
27
What is the only cranial nerve that attaches to the pons?
Trigeminal nerve (CN V)
28
Describe the trigeminal nerve's intracranial, base of skull foramen and extra cranial course?
- Intracranial = inferior to the edge of the tentorium cerebelli between the posterior and middle cranial fossae
- base of skull foramen part of course - sphenoid bone and respective foramen
- Extracranial
= sensory axons from all 3 divisions course, from the superficial and deep structures of the face, posteriorly, towards their respective base of skull foraminae
= motor axons from CNV3 course from the foramen ovale towards the skeletal muscles they supply
29
Trigeminal nerve - sensory innervation - CN V1
CN V1 (ophthalmic nerve) supplies:
- the upper eyelid
- the cornea
- all the conjunctiva
- the skin of the root/bridge/tip of the nose
30
Trigeminal nerve - sensory innervation - CN V2
CN V2 (maxillary nerve) supplies:
- the skin of the lower eyelid
- the skin over the maxilla
- the skin of the ala of the nose
- the skin/mucosa of the upper lip
31
Trigeminal nerve - sensory innervation - CN V3
CN V3 (mandibular nerve) supplies:
- the skin over the mandible
- and temporomandibular joint
- (apart from the angle of the mandible – supplied by C2,3 spinal nerves)
32
What does the great auricular nerve supply?
the great auricular nerve (C2,3) – a sensory branch of the cervical plexus
supplies: -the skin over the angle of the mandible & some of the external ear
33
Trigeminal nerve - CN V1 DEEP sensory territory
- bones & soft tissues of the orbit (except the orbital floor & lower eyelid)
- the upper anterior nasal cavity
- all paranasal sinuses (except the antrum)
- the anterior & posterior cranial fossae
34
Trigeminal nerve - CN V2 - DEEP sensory innervation
- the lower posterior nasal cavity
- the maxilla & maxillary sinus (antrum)
- the floor of the nasal cavity/palate
- the maxillary teeth & associated soft tissues (gingivae & mucosae)
35
Trigeminal nerve - CN V3 - DEEP sensory territory
- the middle cranial fossa
- the mandible
- the anterior 2/3rds of the tongue
- the floor of the mouth
- the buccal mucosa
- the mandibular teeth & associated soft tissues
36
Where is the trigeminal sensory ganglion located?
Middle cranial fossa
37
Trigeminal nerve - motor innervation
- 3 pairs of jaw closing muscles - masseter, temporalis, medial pterygoid
- 1 pair of jaw opening muscles - lateral pterygoid
- tensor veli palatini
- tensor tympani
38
Origin and insertion of masseter
- Origin - zygomatic arch / bone
- Insertion - angle of the mandible
39
Origin and insertion of temporalis
- Origin - lateral aspect of the neurocranium
- Insertion - coronoid process of mandible
40
Origin and insertion of the medial pterygoid
- Origin - pterygoid plates of sphenoid bone
- Insertion - medial side of angle of mandible
41
Origin and insertion of lateral pterygoid
- Origin - pterygoid plates of sphenoid bone
- Insertion - condyle of mandible and articular disc of TMJ
42
What is the facial nerve's connection to the CNS?
anterolateral at pontomeduallry junction
43
Describe the facial nerve's intracranial, base of skull and extra cranial part of the course
- intracranial part of course:
= directly into internal acoustic meatus in the posterior cranial fossa
- base of skull foramen part of course
= internal acoustic meatus, stylomastoid foramen
- extracranial part of course:
= most somatic motor axons pass into the parotid gland then into 1 of the 5 branches that supply the muscles of facial expression
44
The facial nerve's (CN VII) base of skull course through the ? bone
Petrous temporal bone
45
Chorda tympani
the chorda tympani (a branch of CN VII):
- taste buds of the anterior 2/3rds of the tongue
- parasympathetic supply to the submandibular & sublingual salivary glands (salivation)
46
What is the tiniest skeletal muscle in the body?
Stapedius
47
Describe CN VII course from internal acoustic meatus to stapedius
the CN VII at the internal acoustic meatus
to
the CN VII in the facial canal of the petrous temporal bone (the canal connects the internal acoustic meatus to the stylomastoid foramen)
to
the CN VII at the stylomastoid foramen
to the stapedius
48
What is the function of the stapedius muscle?
Reduces stapes movement to protect the internal ear from excessive noise
49
the chorda tympani branch of CN VII connects to the ? nerve branch of CN V3 & contains:
- ?
- for what function ?
the chorda tympani branch of CN VII connects to the lingual nerve branch of CN V3 & contains:
- taste axons (ant. 2/3 tongue)
- parasympathetic axons (salivary glands)
- allows CN VII to supply the sublingual salivary gland
- allows CN VII parasympathetic axons supplying (secretomotor) the submandibular salivary gland
50
What are the muscles of facial expression?
- Frontalis
- Orbicularis oculi
- Elevators of the lips - levator labii superioris
- Orbicularis oris
51
Where is glossopharygneal (CN IX) connection to the CNS?
Lateral aspect of superior medulla oblongata
52
Describe the intracranial, base of skull foramen and extra cranial part of course of glossopharygneal nerve (CN IX)
intracranial part of course:
directly towards jugular foramen in the posterior cranial fossa
base of skull foramen part of course: junction between temporal bone & occipital bone – jugular foramen
extracranial part of course:
axons mainly pass to or from the tongue and pharynx
53
Glossopharygneal (CN IX) supplies general sensory innervation to :
the posterior 1/3rd of the tongue
the mucosa of most of the nasopharynx
the mucosa of all of the oropharynx
the mucosa of some of the laryngopharynx (some overlap with CN X territory)
the palatine tonsil
the eustachian tube
the middle ear cavity
54
What is the clinical relevance of CN IX nerve supply in the head and neck?
CN IX general sensory axons form the afferent limb of the gag reflex
CN IX general sensory afferents are commonly associated with referred pain from the pharynx to the ear and vice versa
55
Glossopharyngeal (CN IX) special sensory to
vallate papillae (with taste buds) of the posterior 1/3rd of the tongue
56
Glossopharyngeal (CN IX) parasympathetic (secretomotor) supply
to the parotid salivary gland
57
Glossopharyngeal visceral afferent supply to ? what is the clinical relevance ?
- carotid sinus baroreceptors and carotid body chemoreceptors
- clinical relevance - carotid sinus massage (management of specific tachyarrythmias)
58
Glossopharyngeal (CN IX) somatic motor supply
Stylopharyngeus (1 longitudinal muscle of the pharynx)
59
Stylopharyngeus innervation
CN IX
60
Vagus nerve (CN X) connection to the CNS
Lateral aspect of the medulla oblongata, immediately inferior to CN IX
61
Describe vagus nerve (CN X) intracranial course, base of skull foramen part of course and extracranial course
intracranial part of course:
directly towards jugular foramen in the posterior cranial fossa
base of skull foramen part of course: junction between temporal bone & occipital bone – jugular foramen
extracranial part of course:
axons supply lots of structures between the palate and the midgut
62
Describe vagus nerve course in the chest (left and right)
- Right CN X - on lateral aspect of trachea
- Left CN X - on lateral aspect of aortic arch
- Both pass posterior to lung root and onto oesophagus
- Both pass through diaphragm with oesophagus
63
The vagus nerves very last parasympathetic axons pass to ?
splenic flexure of the colon
64
Asking the patient to say AH tests what cranial nerves?
CNX and CNV3
65
Unilateral pathology of the vagus nerve will pull uvula ?
AWAY from the NON-functioning side
66
Spinal accessory nerve (CN XI) connection to CNS
via cervical spinal nerve anterior rootlets to the spinal cord
67
Spinal accessory nerve (CN XI) intracranial, base of skull foramen and extra cranial part of course
intracranial part of course:
ascends through foramen magnum then travels towards jugular foramen in posterior cranial fossa
base of skull foramen part of course: junction between temporal bone & occipital bone
extracranial part of course:
axons supply sternocleidomastoid on deep surface, then continue across the posterior triangle of the neck deep to the investing fascia and supply the trapezius
68
What muscles does the spinal accessory nerve (CN XI) supply?
Sternocleidomastoid
Trapezius
69
Hypoglossal nerve (CN XII) connection to the CNS
via many rootlets that attach lateral to the pyramids of the medulla oblongata
70
Intracranial, base of skull foramen and extra cranial part of course of hypoglossal nerve (CN XII)
intracranial part of course:
passes anteriorly towards hypoglossal canal in the posterior cranial fossa
base of skull foramen part of course: occipital bone - hypoglossal canal (anterior wall of foramen magnum)
extracranial part of course:
- descends in neck lateral to carotid sheath
- at level of hyoid bone it passes anteriorly towards the lateral aspect of the tongue
- supplies most of the muscles of the tongue
71
Clinical testing of hypoglossal nerve (CN XII) - what will happen in unilateral CN XII pathology?
- ask patient to stick tongue straight out
- if both CNXII’s are functioning normally the tongue tip remains in the midline on protrusion
- if there is unilateral CN XII pathology the tongue tip will point towards the side of the injured nerve
