Anatomy of Cranial Nerve Testing Flashcards
1
Q
CN V1
A
SENSORY
2
Q
CN V2
A
SENSORY
3
Q
CN V3
A
SENSORY + MOTOR
4
Q
Where is the intracranial part of the CNS between?
A
Between the point of connection of the CNS and their respective base of skull foraminae
5
Q
What are the 3 divisions of the trigeminal nerve? What fibres do they contain?
A
CN V1 - ophthalmic - sensory
CN V2 - maxillary - sensory
CN V3 - mandibular - sensory and motor
6
Q
What is the only cranial nerve to attach to the pons?
A
CN V
7
Q
Where does CN V attach in the intra-cranial cavity?
A
Pons
8
Q
Describe the attachment of CN V to the pons?
A
Laterally
Half way between the midbrain and medulla
9
Q
Name the only nerve in the anterior cranial fossa.
A
CN I (olfactory)
10
Q
What is the function of the olfactory nerve?
A
Sensory - smell
11
Q
Describe the extra cranial part of CN I.
A
Sensory so on body wall
Lays within olfactory mucosa of nasal cavity
12
Q
What is the location of the cranial fossa of CN I?
A
Cribiform plate of ethmoid bone
Anterior cranial fossa
13
Q
What is the intracranial part of CN I (i.e CNS connection)?
A
Olfactory nerves synapse in the olfactory bulb
Then pass through the olfactory tract
14
Q
What is the function of the optic nerve (CN II)?
A
Sensory - vision
15
Q
Describe the extra-cranial part of CN II.
A
Neurons of the retina travel posteriorly via the optic nerve from the posterior hemisphere of the eye through the orbit
16
Q
What is the location of the cranial fossa of CN II?
A
Optic nerve possess through optic canal
Middle cranial fossa
17
Q
What is the intracranial part of CN II?
A
Travels around pituitary stalk to optic chiasm to form the optic tract
18
Q
Where is the connection of CN II to the CNS?
A
Diencephalon
19
Q
How is CN I tested?
A
Note: not done routinely
Ask the patient to smell a familiar smell e.g lemon while covering the contralateral nostril
20
Q
List the 5 ways that CN II can be tested.
A
- Acuity
- Colour
- Fields
- Reflexes
- Fundoscopy
21
Q
What is the function of CN III?
A
Sensory and Motor
Eye movement - motor
Pupil constriction - parasympathetic
22
Q
Where does CN III connect with the CNS?
A
Midbrain
23
Q
What is the intracranial part of CN III?
A
Travels towards the orbit in the lateral walls of the cavernous sinus
24
Q
What is the location of the cranial foraminae of CN III?
A
Superior orbital fissure
25
Describe the extra-cranial part of CN III?
Passes through SOF into orbit to supply extraoccular muscles
26
Where do parasympathetics of CN III synapse? What is their function?
Ciliary ganglion
| Pupillary constriction
27
How is CN III tested?
Shine a light into the patient' eyes to check for pupillary constriction
28
Where does CN IV connect to the CNS?
Midbrain
29
Describe the intracranial part of CN IV?
Travels towards the orbit in the lateral wall of the cavernous sinus
30
Where is the location of the cranial foraminae of CN IV?
Superior orbital fissure
31
Describe the extra-cranial course of CN IV?
Travels through SOF into orbit to supply only 1 muscle
32
What muscle is supplied by CN IV?
Superior oblique
33
At what junction does CN VI connect with the CNS?
Pontomedullary junction
34
Describe the intracranial course of CN VI?
Travels towards the orbit within the cavernous sinus
35
Where is the cranial foraminae of CN VI located?
Superior orbital fissure
36
Describe the extra cranial course of CN VI.
Passes through SOF into orbit to supply only the LATERAL RECTUS muscle
37
What artery runs close to CN VI?
Internal carotid artery
38
How is CN VIII tested?
Rinnie and webber
39
Describe the extra cranial course of CN VIII.
Axons from vestibular and cochlear apparatus
40
Where is the cranial foramina of CN VIII located?
Posterior cranial fossa
Internal acoustic meatus
think 'acoustic is sound'
41
At what junction does CN VIII connect to the CNS?
Pontomedullary junction
42
Describe the intracranial course of CN VIII.
Travels posteromedially from the internal acoustic meatus to the pontomedullary junction
43
What is the function of CN VIII?
SENSORY
| Hearing and balance
44
Describe the function of CN XI (spinal accessory).
MOTOR - to sternocleidomastoid and trapezius
45
Where does CN XI connect with the CNS?
Spinal cord (cervical part)
46
Outline the intracranial course of CN XI.
Ascends through foramen magnum then travels towards jugular foramen
47
What part of the cranial fossa would you find CN XI?
Posterior
48
What is the location of the cranial foramina of CN XI?
Jugular foramen
| Posterior cranial fossa
49
Outline the extra cranial course of CN XI.
Axons supply SCM on deep surface then go across the posterior triangle to supply trapezius and sternocleidomastoid
50
How is CN XI tested?
1. Ask patient to shrug shoulders (should be the same on both sides)
2. Ask them to turn head to flex neck and turn to opposite side
51
What is the function of CN XII?
Motor - to muscles of the tongue
52
Where is the connection of CN XII to the CNS?
Via many rootlets lateral to the pyramids of the MEDULLA OBLONGATA
53
Describe the intracranial course of CN XII?
Passes anteriorly to the hypoglossal canal
54
What is the location of the cranial foramina of CN XII?
Hypoglossal canal
| Posterior cranial fossa
55
Describe the extracranial part of CN XII?
Descends lateral to the carotid sheath
| At level of hyoid, it turns anteriorly towards lateral aspect of the tongue to supply muscles of the tongue
56
CN XII supplies all tongue muscles except?
Palatoglossus
57
How is CN XII tested?
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
58
Where does CN V connect with the CNS?
Pons
59
Describe the intracranial part of CN V and its location in the cranial fossa.
Inferior to the tentorium cerebelli between the MIDDLE and POSTERIOR cranial fossa
60
What is the location of the cranial foramina for CN V1?
SOF
61
What is the location of the cranial foramina for CN V2?
Foramen rotundum
62
What is the location of the cranial foramina for CN V3?
Foramen ovale
63
Describe the extra cranial course of CN V.
From structures of the face to the foramina
| CN V3 - from foramen ovale to appropriate muscle
64
What does CN V1 supply sensory innervation to?
Upper eyelid
Cornea
Conjunctiva
Skin on roof, bridge and tip of nose
65
What does CN V2 supply sensory innervation to?
Skin on lower eyelid
Skin on maxilla
Skin on ala of nose
Skin of upper lip
66
What does CN V3 supply sensory innervation to?
Skin of mandible
| Skin around TMJ
67
What area of skin does CN V3 not supply sensory innervation to?
Skin on the angle of the mandible
68
What nerve supplies the skin on the angle of the mandible?
Greater auricular nerve
| C2, C3
69
What muscles does CN V3 supply? What do each of the muscles do?
Masseter (close)
Temporalis (close)
Medial pterygoid (close)
Lateral pterygoid (open)
70
Outline how CN V sensory innervation is tested.
1. Ask the patient to close their eyes
2. Gently brush the skin in each dermatome with a fine tip of cotton wool
3. Ask the patient to tell you when they feel their skin being touched
4. Compare the 2 sides
Basically, think about all the areas of the face supplied by each division and touch it
71
Outline how CN V motor innervation is tested.
1. Palpate the strength of contraction of the masseter & temporalis by asking patient to clench their teeth
2. Ask the patient to open their jaw against resistance
72
What is the function of the facial nerve?
Sensory (taste)
Motor
Parasympathetics
73
At what junction does CN VII connect to the CNS?
Pontomedullary
74
Outline the intracranial course of CN VII.
Directly into internal acoustic meatus
| Posterior cranial fossa
75
What is the location of the cranial foramina of CN VII to enter and leave and what bone is this in?
Internal acoustic meatus (IN)
Stylomastoid foramen (OUT)
Temporal bone
76
Describe the extra cranial part of CN VII.
Motor axons pass into the parotid gland then to 1 of 5 branches that supply muscles of facial expression
77
What does CN VII provide sensory info to? What branch is this via?
Anterior 2/3rds of tongue
Chorda tympani branch
Taste
78
What part of the temporal bone does CN VII pass through?
Petrous part
79
CN VII has parasympathetic fibres. What do these supply?
Submandibular and sublingual salivary glands
80
CN VII provides motor innervation to the smallest muscle in the body, name this muscle.
Strapedius
81
How can CN VII be tested? (note: you are testing the muscles of facial expression)
```
Ask patient to:
Raise eyebrows
Close eyes tightly
Smile
Puff out cheeks and hold air
```
82
Outline the 5 main functions of CN IX.
```
Special sensory (taste)
Sensory
Motor
Visceral afferent
Parasympathetics
```
83
Where does CN IX connect to the CNS?
Medulla oblongata
84
Describe the intracranial part of CN IX.
Directly towards jugular foramen in posterior cranial fossa
85
What is the cranial foramina for CN IX?
Jugular foramen
86
Describe the extra cranial course of CN IX. State where it goes to and from.
```
Descends towards pharynx and the mouth
To the stylopharyngeus muscle
To the parotid gland
From pharyngeal mucosa
From carotid body and sinus
From posterior 1/3rd of tongue
```
87
How can CN IX be tested?
By eliciting the gag reflex (naughty)
88
Where does CN IX provide special sensory info to (taste)?
Posterior 1/3rd of the tongue
| Vallate papillae
89
Where does CN IX provide parasympathetic innervation to?
Parotid gland
90
What nerve provides innervation to the parotid gland?
CN IX
91
What muscle does CN IX supply?
Stylopharyngeus
92
What does CN IX supply visceral afferent info from (sensory of organs)?
Carotid sinus baroreceptors
| Carotid body chemoreceptors
93
What does CN IX supply sensory innervation to?
The posterior 1/3rd of the tongue
The mucosa of most of the nasopharynx and oropharynx
The mucosa of some of the laryngopharynx (some overlap with CN X territory)
The palatine tonsil
The eustachian tube
The middle ear cavity
94
What are the 4 functions of the vagus nerve?
Sensory
Motor
Visceral afferent
Parasympathetic
95
Where does CN X connect to the CNS?
Medulla
96
Describe the intracranial course of CN X.
Towards jugular foramen
| Posterior cranial fossa
97
Describe the extracranial course of CN X.
LOTS of places between palate and midgut
98
Where does CN X enter and exit the cranial cavity?
Jugular foramen
99
Where does CN X run within the neck?
Carotid sheath
100
CN ? runs inferiorly into the thorax then gives off the recurrent laryngeal nerve to turn back superiorly to supply the muscles of the larynx
CN X
101
Left recurrent laryngeal nerve curves under the?
Arch of the aorta
102
Right recurrent laryngeal curves under the?
Right subclavian artery
103
Where do both CN X's pass to after the neck?
Through the diaphragm with the oesophagus
104
Both CN X's pass anterior to the lung root
FALSE
| Posterior
105
Where do the very last axons of CN X pass onto?
Splenic flexure of the colon
106
How do you test CN X (via muscles of the palate)?
| Explain the results.
Ask patient to say 'ahhhhh'
Motor function
Uvula should lift straight up in midline
Unilateral pathology will pull uvula away from the non-functioning side
107
How do you test CN X (via pharyngeal muscles)?
| Explain the results.
Ask the patient to swallow some water
Watch larynx movement
Splutter may suggest abnormal swallow
108
How do you test CN X (via laryngeal muscles)?
| Explain the results.
Listen to speech
| Hoarseness may suggest abnormal function of muscles of larynx
109
S3, S4, S5 is a....
Bull's eye to the anus lol
