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Cranial Nerves and Clinical Testing Flashcards

1
Q

CN I

  • name.
  • modality.
  • where it connects to CNS.
A
  • Olfactory.
  • Special sensory.
  • Forebrain.
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2
Q

CN II

  • name.
  • modality.
  • where it connects to CNS.
A
  • Optic.
  • Special sensory.
  • Forebrain.
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3
Q

CN III

  • name.
  • modality.
  • where it connects to CNS.
A
  • Oculomotor.
  • Motor.
  • Midbrain.
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4
Q

CN IV

  • name.
  • modality.
  • where it connects to CNS.
A
  • Trochlear.
  • Motor.
  • Midbrain.
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5
Q

CN V

  • name.
  • modality.
  • where it connects to CNS.
A
  • Trigeminal.
  • Both i.e. sensory and motor.
  • Pons.
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6
Q

CN VI

  • name.
  • modality.
  • where it connects to CNS.
A
  • Abducent.
  • Motor.
  • Junction between Pons and medulla.
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7
Q

CN VII

  • name.
  • modality.
  • where it connects to CNS.
A
  • Facial.
  • Both i.e. sensory and motor.
  • Junction between Pons and medulla.
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8
Q

CN VIII

  • name.
  • modality.
  • where it connects to CNS.
A
  • Vestibulocochlear (Acoustic).
  • Special sensory.
  • Junction between pons and medulla.
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9
Q

CN IX

  • name.
  • modality.
  • where it connects to CNS.
A
  • Glossopharyngeal.
  • Both i.e. sensory and motor.
  • Medulla.
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10
Q

CN X

  • name.
  • modality.
  • where it connects to CNS.
A
  • Vagus.
  • Both i.e. sensory and motor.
  • Medulla.
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11
Q

CN XI

  • name.
  • modality.
  • where it connects to CNS.
A
  • Spinal accessory.
  • Motor.
  • Spinal cord.
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12
Q

CN XII

  • name.
  • modality.
  • where it connects to CNS.
A
  • Hypoglossal.
  • Motor.
  • Medulla.
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13
Q

Cranial nerves are visible on which aspect of the brain?

A

Ventral (inferior).

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14
Q

Most cranial nerves exit anteriorly except which and where?

A
  • IV: trochlear, posteriorly.

- VIII: vestibulocochlear, laterally.

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15
Q

What are motor nuclei?

A

Groups of efferent nerve cells sensing axons into a cranial nerve.

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16
Q

What are sensory nuclei?

A

Groups of nerve cells on which the sensory neurons of cranial nerves synapse.

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17
Q

Soma of sensory nerve cells will be found where?

A

In ganglia outside of the CNS.

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18
Q

Which cranial nerve is the only sensory modality that does not synapse in the thalamus prior to reaching the cortex?

A

Olfactory nerve CN I.

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19
Q

Nuclei of origin for CN III, IV and VI are found near where?

A

Midline of the brainstem.

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20
Q

Oculomotor CN III provides parasympathetic supply to which muscles?

A
  • Sphincter pupillae.

- Ciliary muscle.

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21
Q

Oculomotor CN III provides somatic motor supply to which muscles?

A
  • Levator palpebrae superioris.
  • Superior rectus, medial rectus, inferior rectus.
  • Inferior oblique.
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22
Q

Trochlear CN IV provides somatic motor sensation to which muscles?

A

Superior oblique.

LR6SO4AO3.

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23
Q

The only CN to exit posteriorly and crosses midline (small nerve).

A

Trochlear.

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24
Q

Hypoglossal CN XII provides somatic motor function to which muscles?

A
  • Genioglossus.
  • Hyoglossus.
  • Styloglossus.
  • Intrinsic tongue muscles.
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25
Spinal accessory CN XI arises from where?
Cervical spinal cord.
26
Name a function of the trigeminal nerve.
- Somatosensation of face. - Proprioception ass. with chewing. - Motor control.
27
Trigeminal nerve CN V provides the face with which somatosensations?
- Discriminative touch. - Vibration sense. - Pain. - Temperature.
28
Trigeminal nerve CN V allows proprioception ass. with chewing via what structures?
- TMJ. - Muscles of mastication. - Teeth.
29
Trigeminal nerve CN V is responsible for motor control of what structures?
- Muscles of mastication. - Tensor tympani. - Mylohyoid. - Anterior belly of digastric. - Tensor veli palatini.
30
Sensory nucleus of the trigeminal forms a long column of neurons, separated into 3 parts by?
Function.
31
Mesencephalic nucleus of trigeminal sensory nuclei is involved with what?
Providing proprioception info from chewing muscles.
32
Pontine nucleus of trigeminal sensory nuclei is involved with what?
- Discriminative touch. | - Vibration.
33
Spinal nucleus of trigeminal sensory nuclei is involved with what?
- Pain. | - Temperature.
34
What is the significance of the ventral Trigeminothalamic tract?
Most fibres cross in the midline, but some don't - therefore there is a bilateral representation of touch and vibration in the cortex.
35
Facial CN VII provides motor supply to?
- Muscles of facial expression. | - Stapedius.
36
Facial CN VII provides parasympathetic innervation to?
- Pterygopalatine. | - Submandibular ganglia.
37
Facial CN VII provides taste to?
- Anterior 2/3 of the tongue via chorda tympani.
38
Facial CN VII provides taste to the anterior 2/3 of the tongue via which branch?
Chorda tympani.
39
Glossopharyngeal CN IX receives tactile sense, pain and temperature sense from where?
- Posterior tongue. - Phayngotympanic tube. - Upper pharynx.
40
Glossopharyngeal CN IX provides taste to?
- Posterior 1/3 of the tongue.
41
Glossopharyngeal CN IX provides parasympathetic fibres to?
- Otic ganglion of parotid gland.
42
Glossopharyngeal CN IX provides motor supply to?
Stylopharyngeus.
43
Vagus CN X receives tactile sense, pain and temperature sense from where?
- Pharynx. - Larynx. - Trachea. - Oesophagus. - Thoracic and abdominal viscera.
44
CN X provides taste sensation to?
Epiglottis.
45
CN X provides sympathetic innervation to ganglia serving?
Thoracic and abdominal viscera.
46
CN X provides motor supply to striated muscle of the?
- Pharynx. | - Larynx.
47
Which CNs have solitary nuclei?
- CN VII. - CN IX. - CN X.
48
Which cranial nerves share the superior and inferior salivatory nuclei?
CN VII and IX.
49
Superior and inferior salivatory nuclei provide parasympathetic efferents to ganglia of what?
- Salivary glands. | - Pterygopalatine ganglion.
50
Nucleus ambiguus is shared by which cranial nerves?
CN IX, IX and the cranial part of XI.
51
Nucleus ambiguus provides motor efferents to?
Muscles of the: - Pharynx. - Larynx. - Upper oesophagus.
52
What is the corticobulbar tract in relation to cranial nerves?
The part of the pyramidal tract that connects the motor cortex to cranial nerves.
53
The facial nucleus only receives bilateral input to which part?
Part controlling the muscles of the upper face i.e. forehead and around eyes.
54
The facial nucleus only receives crossed input to which part?
Part controlling the muscles of the lower half of the face.
55
What is the reticular formation?
Loose network in the central core of the brainstem consisting of: - Aggregated cells with cells bodies, axons and dendrites. Exists distinct from long pathways e.g. corticospinal tract.
56
Name a function of a centre contained within the reticular formation.
1. Integration of cranial nerve reflexes. 2. Conduction and modulation of pain. 3. Influencing voluntary movement. 4. Regulation of autonomic activity. 5. Integration of some basic functions e.g. respiration and sleep. 6. Activating the cerebral cortex.
57
Centres within the reticular formation that activate the cerebral cortex are a major component of what?
The Ascending Reticular Activating System.
58
A medial bilateral lesion of the brainstem reticular formation at or above the pons causes what?
Irreversible coma.
59
The extracranial part of CN I (olfactory) is found where?
Within olfactory mucosa in the nasal cavity.
60
Where is the CN I (Olfactory) cranial foramina?
- Cribriform plate of the ethmoid bone in the anterior cranial fossa.
61
Where is CN I (Olfactory) found at its intracranial part/connection with the CNS?
- The olfactory nerves synapse in the olfactory bulb and then pass through the olfactory tract to cortical areas.
62
The extracranial part of CN II (Optic) is found where?
- Neurons of the retina travel posteriorly via the optic nerve from the posterior hemisphere of the eye through the orbit.
63
Where is the CN II (Optic) cranial foramina?
- CN II passes through the OPTIC CANAL in the middle cranial fossa.
64
The intracranial part of CN II (Optic) is found where?
- CN II travels around the pituitary stalk to the optic chiasm to form the optic tract.
65
Where does CN II (Optic) connect with the CNS?
Diencephalon.
66
How is CN I (olfactory) clinically tested?
- Not routinely tested. | - Ask patient to smell a familiar smell while covering the contralateral nostril.
67
How is CN II (optic) clinically tested?
- Acuity (snellen chart). - Colour (Ishihara plates - colour blindness). - Fields (quadrants). - Reflexes (pupillary light reflexes). - Fundoscopy.
68
Where does CN III (oculomotor) connect with the CNS?
Midbrain i.e. mesencephalon.
69
Where is the intracranial part of CN III (oculomotor) found?
Travelling towards the orbit in the lateral wall of the cavernous sinus.
70
What is CN III (oculomotor) cranial foramina?
- SUPERIOR ORBITAL FISSURE.
71
Where is the extracranial part of CN III (oculomotor) located?
Passing through superior orbital foramina into the orbit to supply all but two extraocular muscles.
72
Where do the extracranial parasympathetics of CN III (oculomotor) synapse?
In the ciliary ganglion.
73
How are CN III (oculomotor) parasympathetics clinically tested?
- Shine a light and look for pupillary constriction. (Tested alongside optic nerve).
74
Where does CN IV (trochlear) connect with the CNS?
- Midbrain i.e. mesencephalon.
75
Where is the intracranial part of CN IV (trochlear) located?
Travelling towards the orbit in the lateral wall of the cavernous sinus.
76
What is the cranial foramina of CN IV (trochlear)?
Superior orbital fissure.
77
Where is the extracranial part of CN IV (trochlear) located?
Passing through superior orbital fissure into the orbit to supply only superior oblique. LR6SO4AO3.
78
Where does CN VI (abducent) connect with the CNS?
Pontomedullary junction.
79
Where is the intracranial part of CN VI (abducent) located?
Travelling towards the orbit within the cavernous sinus.
80
What is the cranial foramina CN VI (abducent)?
Superior orbital fissure.
81
Where is the extracranial part of CN VI (abducent) located?
Passing through the superior orbital fissure into the orbit to supply only the lateral rectus. LR6SO4AO3.
82
CN III supplies which extra-ocular muscles?
- Superior rectus. - Inferior oblique. - Inferior rectus. - Medial rectus.
83
CN IV supplies which extra-ocular muscles?
- Superior oblique.
84
CN VI supplies which extra-ocular muscles?
- Lateral rectus.
85
Where does CN VIII (vestibulocochlear/acoustic) connect with the CNS?
Pontomedullary junction.
86
Where is the extracranial part of CN VIII (vestibulocochlear/acoustic) found?
As axons from the cochlear and vestibular apparatus.
87
What is the cranial foramina of CN VIII (vestibulocochlear/acoustic)?
Internal acoustic meatus found in the posterior cranial fossa.
88
Where is the intracranial part of CN VIII (vestibulocochlear/acoustic) found?
Travelling posteromedially from the internal acoustic meatus to the pontomedullary junction.
89
How is CN VIII (vestibulocochlear/acoustic) clinically tested?
- Rinnie and Weber tests.
90
Where does CN XI (spinal accessory) connect with the CNS?
Cervical spinal cord.
91
Where is the intracranial part of CN XI (spinal accessory) found?
Ascending through foramen magnum then travelling towards the jugular foramen in the posterior cranial fossa.
92
What is the cranial foramina CN XI (spinal accessory)?
Jugular foramina in the posterior cranial fossa.
93
Where is the extracranial part of CN XI (spinal accessory) located?
As axons supplying the sternocleidomastoid on its deep surface and then continuing across the posterior triangle to supply trapezius and sternocleidomastoid.
94
How is CN XI (spinal accessory) tested clinically?
- Shrug shoulders. | - Ask to turn head to flex neck and then turn towards opposite side.
95
Where do the cutaneous nerves of the cervical plexus pass in relation to midpoint of the posterior border of sternocleidomastoid?
DEEP. | NB they do NOT pass deep to trapezius
96
Where does CN XII (hypoglossal) connect with the CNS?
Via many rootlets lateral to the pyramids of the medulla oblongata.
97
Where is the intracranial part of CN XII (hypoglossal) found?
Passing anteriorly to the hypoglossal canal.
98
What is the cranial foramina of CN XII (hypoglossal)?
Hypoglossal canal found in the posterior cranial fossa.
99
Where is the extracranial part of CN XII (hypoglossal) found?
- Descending laterally to the carotid sheath. | - At level of hyoid turn anteriorly towards lateral aspect of the tongue to supply most muscles of the tongue.
100
How is CN XII (hypoglossal) clinically tested?
Stick tongue straight out. - If tongue remains in midline, both CN XII's are functioning normally. - If unilateral CN XII pathology, tongue tip will point towards the side of the injured nerve.
101
Name the 3 divisions of CN V (trigeminal) and their modalities.
- Ophthalmic (CNV1) - Sensory. - Maxillary (CNV2) - Sensory. - Mandibular (CNV3) - Sensory and motor.
102
Where does CN V (trigeminal) connext with the CNS?
Laterally to pons - midway between midbrain and medulla.
103
Where is the intracranial part of CN V (trigeminal) found?
Inferior to the edge of tentorium cerebelli between posterior and middle cranial fossae.
104
What is the cranial foramina of CN V1 (ophthalmic division of trigeminal)?
- Superior orbital fissure.
105
What is the cranial foramina of CN V2 (maxillary division of trigeminal)?
- Foramen rotundum.
106
What is the cranial foramina of CNV3 (mandibular division of trigeminal)?
- Foramen ovale.
107
Where is the extracranial part of CN V (trigeminal) located?
Sensory axons of all 3 divisions run from the superficial AND deep facial structures posteriorly towards their cranial foraminae. Motor axons from CNV3 (mandibular) course from foramen ovale towards their supplied skeletal muscle.
108
CN V1 (ophthalmic division) supplies what?
- Upper eyelid. - Cornea (corneal reflex). - All conjunctiva. - Skin of root/bridge/tip of nose.
109
CN V2 (maxillary division) supplies what?
- Skin of lower eyelid. - Skin over maxilla. - Skin of ala of nose. - Skin/mucosa of upper lip.
110
CN V3 (mandibular division) supplies what?
- Skin over mandible and temporomandibular joint APART from angle of mandible (supplied by C2,3 spinal nerves).
111
What supplies the skin over the angle of the mandible and some of the external ear?
Great auricular nerve (C2,3). | - Sensory branch of cervical plexus.
112
What is the deep sensory territory of CN V1 (ophthalmic division)?
- Bones and soft tissues of the orbit (except orbital floor and lower eyelid). - Upper anterior nasal cavity. - Paranasal sinuses (except maxillary). - Anterior and posterior cranial fossae.
113
What is the deep sensory territory of CN V2 (maxillary division)?
- Lower posterior nasal cavity. - Maxilla and maxillary sinus. - Floor of the nasal cavity/palate. - Maxillary teeth and associated soft tissues (gingivae & mucosae).
114
What is the deep sensory territory of CN V3 (mandibular division)?
- Middle cranial fossa. - Mandible. - Anterior 2/3 of tongue. - Floor of the mouth. - Buccal mucosa. - Mandibular teeth and associated soft tissues.
115
What are the three pairs of jaw closing muscles?
- Masseter. - Temporalis. - Medial pterygoid.
116
What is the 1 pair of jaw opening muscles?
- Lateral pterygoid.
117
What nerve is responsible for opening and closing the jaw?
CNV3 - mandibular division of trigeminal.
118
How is sensory function of CN V (trigeminal) clinically tested?
Close patient's eyes and gently brush skin in each dermatome (CN V1, V2, V3) with fine cotton wool. - Ask patient to tell you when they are being touched. - Compare left and right.
119
How is motor function of CN V (trigeminal) clinically tested?
- Palpate strength of contraction of masseter and temporalis by asking patient to clench their teeth. - Ask patient to open jaw against resistance.
120
What nerves form the first part of the afferent limb of the blink/corneal reflex?
Long ciliary nerves.
121
Describe the dermatome of CNV1 (ophthalmic division).
Forehead, upper eyelid and tip of nose.
122
Describe the dermatome of CNV2 (maxillary division).
Upper-cheek, lower eyelid, upper lip and nostril of nose.
123
Describe the dermatome of CNV3 (mandibular division).
Mid-cheek, lower lip and chin.
124
What are the modalities of CN VII (facial)?
- Special sensory (taste). - Motor. - Parasympathetic.
125
Where does CN VII (facial) connect to the CNS?
Anterolaterally at the pontomedullary junction.
126
Where is the intracranial part of CN VII (facial) located?
Directly in the internal acoustic meatus of the posterior cranial fossa.
127
What is the cranial foramina of CN VII (facial)?
- Internal acoustic meatus - IN. - Stylomastoid foramen - OUT. Located in temporal bone.
128
Where is the extracranial part of CN VII (facial) found?
As mostly somatic motor axons passing into the parotid gland and then into 1 of 5 branches supplying the muscles of facial expression.
129
CN VII (facial) courses through the base skull via which part of the temporal bone?
Petrous part.
130
Which branch of CN VII (facial) supplies taste to the anterior 2/3 of the tongue?
- Chorda tympani.
131
In addition to supplying taste to anterior 2/3 of tongue, Chorda tympani branch of CN VII (facial) provides parasympathetic supply to what?
Submandibular and sublingual glands - salivation.
132
The facial canal connects what?
Internal acoustic meatus to stylomastoid foramen.
133
What nerve supplies the Stapedius muscle?
CN VII (facial).
134
What is the function of the Stapedius muscle?
Reduces stapes movement to protect the internal ear from excessive noise.
135
Name the muscles of facial expression.
- Frontalis. - Orbicularis oculi - Elevators of lips - Orbicularis oris
136
How is motor function of CN VII (facial) clinically tested?
- Raise eyebrows (frontalis). - Close eyes tightly (orbicularis oculi). - Smile (lip elevators). - Puff out cheeks (orbicularis oris).
137
What are the modalities of CN IX (glossopharyngeal)?
- Special sensory (taste). - Sensory. - Motor. - Visceral afferent. - Parasympathetic.
138
Where does CN IX (glossopharyngeal) connect with the CNS?
- Lateral aspect of the superior part of medulla oblongata.
139
Where is the intracranial part of CN IX (glossopharyngeal) located?
Directly towards the jugular foramen in the posterior cranial fossa.
140
What is the cranial foramina of CN IX (glossopharyngeal)?
Jugular forameb.
141
Where is the extracranial part of CN IX (glossopharyngeal) located?
Descending towards the pharynx and the mouth, to the: - Stylopharyngeus muscle. - Parotid gland. - Pharyngeal mucosa. - Carotid body and sinus. - Posterior 1/3 of tongue.
142
CN IX (glossopharyngeal) has special sensory supply to what?
- Vallaye papillae of posterior 1/3 of tongue.
143
CN IX (glossopharyngeal) has parasympathetic supply (secretomotor) to what?
Parotid gland.
144
CN IX (glossopharyngeal) has supplies visceral afferents to what?
- Carotid sinus baroreceptors. | - Carotid body chemoreceptors.
145
What is the clinical relevance of CN IX (glossopharyngeal) supply to carotid sinus baroreceptors?
Allows for carotid sinus massage in the management of specific tachyarrhythmias.
146
CN IX (glossopharyngeal) is responsible for general sensory supply to?
- Posteiro 1/3 of tongue. - Most mucosa of nasopharynx and oropharynx. - Some mucosa of laryngopharynx (CN X overlap). - Palatine tonsil. - Eustachian tube. - Middle ear cavity.
147
What forms the afferent limb of the gag reflex?
CN IX (glossopharyngeal) general sensory axons.
148
General sensory afferents of which nerve are commonly associated with referred pain from the pharynx to the ear and vice versa?
CN IX (glossopharyngeal).
149
How is general sensory function of CN IX (glossopharyngeal) tested?
Eliciting gag reflex.
150
What are the modalities of CN X (vagus)?
- Sensory - Motor - Visceral afferent - Parasympathetic
151
Where does CN X (vagus) connect with the CNS?
Lateral aspect of medulla oblongata immediately inferior to CN IX (glossopharyngeal).
152
Where is the intracranial part of CN X (vagus) found?
Heading directly towards the jugular foramen in posterior cranial fossa.
153
What is the cranial foramina of CN X (vagus)?
Jugular foramen.
154
Where is the extracranial part of CN X (vagus)?
Axons supply many structures located between the palate and midgut.
155
Where is CN X (vagus) located in the neck?
Within the carotid sheath - posterior to (and between) the common carotid artery and internal jugular vein.
156
CN X (vagus) runs inferiorly in thorax and gives off recurrent laryngeal (heads back superiorly) to supply what?
Muscles of the larynx.
157
Where does the left recurrent laryngeal nerve curve?
Under arch of aorta.
158
Where does the right recurrent laryngeal nerve curve?
Under right subclavian artery.
159
Where is the right CN X (vagus) found in the chest?
Lateral aspect of trachea.
160
Where is the left CN X (vagus) found in the chest?
Lateral aspect of aortic arch.
161
Both the L&R CN X (vagus) pass posteriorly to what in the chest?
Posterior to lung root and then onto oesophagus.
162
The very last parasympathetic axons of CN X (vagus) pass to what structures in the abdomen?
Splenic flexure of the colon.
163
How are the muscles of palate supplied by CN X (vagus) tested?
Say ahhhhhh. - Uvula should lift straight in the midline. - Unilateral pathology will pull the uvula away from the non-functioning side. NB this also tests CNV3.
164
How are the pharyngeal muscles supplied by CN X (vagus) tested?
Swallow water. - Watch larynx movement. - Splutter may suggest abnormal swallow.
165
How are the laryngeal muscles supplied by CN X (vagus) tested?
Listen to speech. | - Hoarseness may suggest abnormal function of larynx muscles.

CNS CLERKSHIP (43 decks)

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