year 4 CMS > Cranial Nerves > Flashcards

Cranial Nerves Flashcards

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1
Q

What are considered the most important neural structures relevant to dentists?

A

Cranial nerves

They are the nerve supply to all of the structures in the head and neck.

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2
Q

Cranial nerves underpin the anatomy and function of which regions?

A

Head and neck

Understanding their function is crucial for dental practice.

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3
Q

True or false: Understanding the function and anatomy of cranial nerves is relevant to dental practice every day.

A

TRUE

Recognizing when cranial nerves are not functioning properly is essential for diagnosing various diseases.

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4
Q

Which cranial nerves require detailed knowledge for dental practice?

A
  • CN V – trigeminal
  • CN VII – Facial

These nerves are crucial for anaesthetising during dental treatment or avoiding damage during surgery.

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5
Q

Fill in the blank: Understanding all of the cranial nerves is important, but some are more important than _______.

A

others

The focus should be on the nerves that are frequently encountered in dental practice.

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6
Q

What is one example of the role of cranial nerves related to pain control?

A
  • Local anaesthesia

Cranial nerves play a crucial role in pain management and control.

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7
Q

Name a condition that cranial nerves can help diagnose related to facial weaknesses.

A
  • Facial weaknesses/palsies

Cranial nerves are involved in assessing facial muscle function.

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8
Q

What is one of the other CMS topics that cranial nerves are involved in diagnosing?

A
  • TIA/Stroke

Cranial nerves can assist in identifying central nervous system issues.

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9
Q

True or false: Cranial nerves are involved in avoiding damage during surgical procedures.

A

TRUE

Understanding cranial nerve functions is essential for safe surgical practices.

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10
Q

What system is referred to when discussing the central nervous system?

A
  • Central nervous system

This includes the brain and spinal cord.

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11
Q

What does the peripheral nervous system control?

A
  • Somatic actions
  • Autonomic functions

The peripheral nervous system connects the central nervous system to the limbs and organs.

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12
Q

Fill in the blank: The somatic nervous system controls _______ actions of skin/muscles.

A

external

It is responsible for voluntary movements.

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13
Q

Fill in the blank: The autonomic nervous system controls _______ such as glands and organs.

A

internals

It regulates involuntary bodily functions.

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14
Q

What is the role of the sympathetic nervous system?

A
  • Fight and flight

It prepares the body for stressful situations.

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15
Q

What is the role of the parasympathetic nervous system?

A
  • Rest and digest

It promotes relaxation and conservation of energy.

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16
Q

What do afferent nerves do?

A
  • Carry sensory information to the central nervous system

They transmit signals from sensory receptors.

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17
Q

What do efferent nerves do?

A
  • Carry motor commands from the central nervous system

They transmit signals to muscles and glands.

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18
Q

What does embryology study in relation to cranial nerves?

A
  • Development of the face

Understanding embryology is important for grasping cranial nerve functions.

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19
Q

How many paired cranial nerves arise directly from the brain?

A

Twelve

These nerves are numbered based on their origin from the brain.

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20
Q

Which cranial nerves arise from the cerebrum?

A
  • Olfactory (1)
  • Optic (2)

All other cranial nerves originate from the brainstem.

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21
Q

Where does the Oculomotor nerve arise?

A

Junction of midbrain and pons

It is the third cranial nerve.

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22
Q

Which cranial nerve arises from the midbrain?

A

Trochlear (4)

It is the fourth cranial nerve.

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23
Q

The Trigeminal nerve arises from which part of the brain?

A

Pons

It is the fifth cranial nerve.

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24
Q

Which cranial nerves arise from the junction of pons and medulla?

A
  • Abducens (6)
  • Facial (7)
  • Vestibulocochlear (8)

These nerves are responsible for various sensory and motor functions.

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25
The **Glossopharyngeal**, **Vagus**, **Accessory**, and **Hypoglossal** nerves arise from which part of the brain?
Medulla oblongata ## Footnote These are cranial nerves 9 through 12.
26
List the **cranial nerves** in order.
* Olfactory (1) * Optic (2) * Oculomotor (3) * Trochlear (4) * Trigeminal (5) * Abducens (6) * Facial (7) * Vestibulocochlear (8) * Glossopharyngeal (9) * Vagus (10) * Accessory (11) * Hypoglossal (12) ## Footnote These nerves perform various sensory and motor functions.
27
What is the **foramen rotundum** associated with?
Maxillary nerve ## Footnote It is one of the foramina through which cranial nerves exit the cranium.
28
What does the **foramen ovale** transmit?
Mandibular nerve ## Footnote This foramen is another exit point for cranial nerves.
29
The **internal acoustic meatus** is associated with which cranial nerve?
Facial nerve ## Footnote This foramen allows the facial nerve to exit the cranium.
30
Fill in the blank: A mnemonic to remember cranial nerves is: **Only One Of The Two Athletes Felt Very Good, Victorious And ______**.
Healthy ## Footnote This mnemonic helps in recalling the order of cranial nerves.
31
What is the **function** of the **Olfactory nerve (1)**?
S (smell) ## Footnote Responsible for small and conveys information from the nose to olfactory areas in temporal lobes.
32
What is the **function** of the **Optic nerve (2)**?
S (vision) ## Footnote The first component of the visual pathways that convey vision from the retinas of the eyeballs to the visual cortex of the brain.
33
What is the **function** of the **Oculomotor nerve (3)**?
M (most of the muscles for eye movement + the pupillary sphincter) ## Footnote Responsible for controlling most eye movements and the constriction of the pupil.
34
What is the **function** of the **Trochlear nerve (4)**?
M (one eye movement muscle, the superior oblique) ## Footnote Controls the superior oblique muscle, which is responsible for downward and lateral eye movement.
35
What is the **function** of the **Trigeminal nerve (5)**?
B (both sensory and motor) ## Footnote Responsible for sensation in the face and motor functions such as biting and chewing.
36
What is the **function** of the **Abducens nerve (6)**?
M (one muscle of eye movement, lateral rectus) ## Footnote Controls the lateral rectus muscle, which abducts the eye.
37
What is the **function** of the **Facial nerve (7)**?
B (has sensory, motor, and glandular functions) ## Footnote Responsible for facial expressions, taste sensations, and controlling salivary and lacrimal glands.
38
What is the **function** of the **Vestibulocochlear nerve (8)**?
S (hearing and balance) ## Footnote Responsible for transmitting sound and equilibrium information from the inner ear to the brain.
39
What is the **function** of the **Glossopharyngeal nerve (9)**?
B (both sensory and motor) ## Footnote Involved in taste, swallowing, and the gag reflex.
40
What is the **function** of the **Vagus nerve (10)**?
B (both sensory and motor) ## Footnote Controls functions of the heart, lungs, and digestive tract.
41
What is the **function** of the **Accessory nerve (11)**?
M ## Footnote Responsible for motor innervation to the sternocleidomastoid and trapezius muscles.
42
What is the **function** of the **Hypoglossal nerve (12)**?
M ## Footnote Controls tongue movements necessary for speech and swallowing.
43
What mnemonic helps remember the **functions** of cranial nerves?
Some Say Marry Money But My Brother Says Big Brains Matter Most ## Footnote Each word corresponds to the sensory (S), motor (M), or both (B) functions of the cranial nerves.
44
Name the **seven types of information** transmitted by cranial nerves.
* GSS (general somatic sensory) * GVS (general visceral sensory) * SSS (special somatic sensory) * SVS (special visceral sensory) * GSM (general somatic motor) * GVM (general visceral motor) * SVM (special visceral motor) ## Footnote These types categorize the information transmitted towards the brain (afferent) and from the brain to muscles (efferent).
45
What does **GSS** stand for in cranial nerve information types?
General Somatic Sensory ## Footnote Receives sensory information from the skin, skeletal muscles, and joints.
46
What does **GVS** stand for in cranial nerve information types?
General Visceral Sensory ## Footnote Receives sensory information from the viscera (organs).
47
What does **SSS** stand for in cranial nerve information types?
Special Somatic Sensory ## Footnote Receives sensory information from the ectodermal retina, cochlear, and vestibular apparatus.
48
What does **SVS** stand for in cranial nerve information types?
Special Visceral Sensory ## Footnote Receives sensory information from the endodermal nose and tongue.
49
What does **GSM** stand for in cranial nerve information types?
General Somatic Motor ## Footnote Provides motor innervation to skeletal muscles.
50
What does **GVM** stand for in cranial nerve information types?
General Visceral Motor ## Footnote Provides secretomotor function to smooth muscle and glands, particularly of the gut.
51
What does **SVM** stand for in cranial nerve information types?
Special Visceral Motor ## Footnote Provides motor innervation to skeletal muscles of the pharyngeal arches.
52
What are the two **reflexes** involved in the off-branches of the axons?
* Pupillary light reflex * Accommodation reflex ## Footnote The pupillary light reflex involves constriction of the pupil in response to bright light, while the accommodation reflex involves changes in lens shape and pupillary constriction when viewing close objects.
53
What does **consensual** mean in the context of light reflexes?
Occurs in both eyes at the same time ## Footnote For example, shining a bright light in one eye causes constriction in both eyes due to the crossover of nerve fibers.
54
A lesion in one eye may lead to **blindness** in that eye due to what condition?
Increase in intraocular pressure from glaucoma ## Footnote Damage to the optic nerve can result in visual field defects.
55
What visual field defect is caused by a lesion affecting the **optic chiasma**?
Bitemporal hemianopia ## Footnote This condition results in half-blindness in both eyes in the temporal fields of vision.
56
What chart is used to test for **visual acuity**?
Snellen chart ## Footnote Visual loss should ideally be measured by an optometrist.
57
The **pupillary responses** can be tested by sensitivity to light and via what reflex?
Accommodating reflex ## Footnote The visual field can also be assessed to determine the field of view.
58
Which cranial nerves control **eye movements**?
* Oculomotor (3) * Trochlear (4) * Abducens (6) ## Footnote These nerves work together for the movement of the eye.
59
What does the term **GSM** stand for in relation to the oculomotor nerve?
General somatic motor ## Footnote This provides motor innervation to skeletal muscles, including four extrinsic muscles of the eye.
60
What does the term **GVM** refer to in the context of the oculomotor nerve?
General visceral motor ## Footnote This provides secretomotor function to smooth muscle and glands, particularly of the gut, referring to the pupillary sphincter.
61
What are the clinical features of an **oculomotor nerve injury** associated with the eye?
* Drooping (ptosis) * 'Down and Out' position * Dilated pupil ## Footnote These features result from paralysis of specific eye muscles and unopposed actions of others.
62
What causes the **'Down and Out' position** of the eye at rest in oculomotor nerve palsy?
Paralysis of superior, inferior, and medial rectus and inferior oblique ## Footnote This results in unopposed activity of the lateral rectus and superior oblique muscles.
63
What is the function of **Nerve 4 – Trochlear**?
Supplies the superior oblique muscle of the contralateral eye ## Footnote This muscle depresses and intorts the eyeball.
64
What does **intorts** mean?
To twist in and out, to twine, to wring, etc. ## Footnote It describes the action of the superior oblique muscle.
65
What condition results from **palsy** of the trochlear nerve?
Vertical diplopia ## Footnote This condition is known as blurring or double vision, exacerbated when looking downwards and inwards.
66
What are common causes of **palsy** in the trochlear nerve?
* Microvascular damage (e.g., diabetes mellitus, hypertension) * Cavernous sinus thrombosis * Raised intracranial pressure ## Footnote These conditions can affect the function of the trochlear nerve.
67
What is the function of **Nerve 6 – Abducens**?
Supplies the lateral rectus muscle, which abducts the eyeball ## Footnote Abduction means to rotate the gaze away from the midline.
68
What is tested during the examination of the **abducens nerve**?
Eye movements in conjunction with oculomotor and trochlear nerves ## Footnote Movements are tested by following a finger/pen tip in an H-shaped movement.
69
What are the clinical features of **palsy** in the abducens nerve?
* Diplopia * Inability to abduct the eye * Head rotation to compensate ## Footnote Patients may rotate their head to allow the eye to look sideways.
70
What is the **largest cranial nerve**?
Trigeminal nerve ## Footnote The trigeminal nerve is associated with derivatives of the 1st pharyngeal arch.
71
Name the **three branches** of the trigeminal nerve.
* Ophthalmic * Maxillary * Mandibular ## Footnote Each branch has distinct sensory and motor functions.
72
What do the **sensory functions** of the trigeminal nerve innervate?
* Skin * Mucous membranes * Sinuses of the face ## Footnote Their distribution pattern is similar to the dermatome supply of spinal nerves.
73
Which branch of the trigeminal nerve has **motor fibres**?
Mandibular branch ## Footnote It innervates the muscles of mastication.
74
List the **muscles of mastication** innervated by the mandibular branch.
* Medial pterygoid * Lateral pterygoid * Masseter * Temporalis ## Footnote These muscles are essential for chewing.
75
What is the **corneal reflex**?
Involuntary blinking of eyelids ## Footnote The ophthalmic nerve detects stimuli on the cornea and triggers the facial nerve to contract the orbicularis oculi muscle.
76
What areas does the **ophthalmic branch** of the trigeminal nerve innervate?
* Scalp * Forehead * Frontal and ethmoid sinuses * Upper eyelid * Cornea * Dorsum of the nose ## Footnote It also supplies the lacrimal gland.
77
What are the **six branches** of the maxillary branch of the trigeminal nerve?
* Middle meningeal nerve * Nasopalatine nerve * Greater palatine nerve * Lesser palatine nerve * Zygomatic nerve * Infraorbital nerve ## Footnote These branches provide sensation and parasympathetic innervation.
78
What does the **mandibular branch** of the trigeminal nerve supply?
* Mucous membranes of the oral cavity * External ear * Lower lip * Chin * Anterior 2/3 of the tongue * Lower molar, incisor, and canine teeth ## Footnote It is important for local anaesthetic applications.
79
What is the **function** of the mandibular nerve's motor supply?
* Muscles of mastication * Tensor veli palatini * Tensor tympani * Anterior belly of digastric * Mylohyoid muscle ## Footnote These muscles are involved in jaw movement.
80
What is a **red flag** in dentistry related to the trigeminal nerve?
Unexplained or new onset numbness ## Footnote This should be considered a malignancy until proven otherwise.
81
What is **trigeminal neuralgia**?
A painful nerve malfunction in the distribution of the trigeminal nerve ## Footnote It can cause severe facial pain.
82
True or false: The functions of the trigeminal nerve are often confused with the functions of the **facial nerve**.
TRUE ## Footnote It is important to distinguish between the sensory and motor functions of both nerves.
83
What is the **facial nerve** associated with?
Derivatives of the 2nd pharyngeal arch ## Footnote The facial nerve plays a crucial role in motor and sensory functions.
84
What are the **motor functions** of the facial nerve?
* Moves the muscles of facial expression * Moves other muscles of the face and neck such as: * Posterior belly of the digastric * Stylohyoid * Stapedius muscle in the ear ## Footnote The facial nerve is primarily responsible for facial movements.
85
What is the **sensory function** of the facial nerve?
* Supplies a small part of the concha of the external ear * Provides taste sensation to the anterior two-thirds of the tongue via the chorda tympani * Supplies parasympathetic function to glands in the head and neck ## Footnote The trigeminal nerve supplies most sensory information from the skin of the face and oral cavity.
86
What glands does the facial nerve provide **parasympathetic function** to?
* Submandibular and sublingual salivary glands * Nasal, palatine and pharyngeal mucous glands * Lacrimal glands ## Footnote The lacrimal glands produce tears to lubricate the eye.
87
After exiting the skull, the facial nerve is termed the **motor root** of the facial nerve when it runs anterior to the outer ear. True or False?
TRUE ## Footnote This marks the transition of the nerve's function as it continues into the parotid gland.
88
What are the **five branches** of the facial nerve within the parotid gland?
* Temporal branch * Zygomatic branch * Buccal branch * Marginal mandibular branch * Cervical branch ## Footnote These branches innervate the muscles of facial expression.
89
What is the **chorda tympani**?
A branch of the facial nerve responsible for taste sensation in the anterior 2/3 of the tongue ## Footnote It 'hitchhikes' with the lingual nerve from the infratemporal fossa.
90
What happens if there is a lesion in the **chorda tympani**?
Leads to reduced salivation and loss of taste on the ipsilateral two-thirds of the tongue ## Footnote Ipsilateral means belonging to or occurring on the same side of the body.
91
What does a lesion in the **nerve to the stapedius** lead to?
Ipsilateral hyperacusis ## Footnote Hyperacusis is a hypersensitivity to sound.
92
What is the most common cause of an **intracranial lesion** of the facial nerve?
Infection related to the external or middle ear ## Footnote If no definitive cause can be found, the condition is termed Bell’s palsy.
93
What is the **anatomy** involved in facial nerve control?
* Facial nerve controls muscles of facial expression * Lower face: controlling fibres travel from cortex to brainstem, cross to contralateral facial nerve * Upper face: fibres split, half cross to contralateral, half remain ipsilateral ## Footnote Understanding the anatomy is crucial for differentiating between Bells palsy and intracranial lesions.
94
What are the symptoms of **intracranial lesions** affecting the facial nerve?
* Contralateral facial weakness of the lower face * Muscles of the upper face show no abnormalities * Weak smile * Able to close eye tightly * Wrinkle forehead symmetrically ## Footnote Intracranial lesions likely damage the motor cortex, leading to central facial weakness.
95
What are the symptoms of **Bells palsy**?
* Ipsilateral facial weakness of both upper and lower face * Unable to wrinkle forehead * Unable to tightly close eye * Unable to smile on affected side ## Footnote Bells palsy results from damage to the facial nerve in the brainstem.
96
If **facial weakness** is isolated to the lower face, what is the most likely diagnosis?
Stroke ## Footnote This indicates that the upper motor neurone is likely affected.
97
If **facial weakness** involves both the upper and lower face, what should you look for?
Associated symptoms for Bells Palsy ## Footnote Symptoms may include younger patients and slow onset of symptoms.
98
What can cause **temporary facial nerve weakness** during a dental procedure?
Misplaced inferior dental block ## Footnote Accidental injection into the parotid gland can cause paralysis of all facial muscles.
99
What is a recommended technique to reduce the risk of **local anaesthetic complications**?
Contact the bone of the ramus and withdraw the needle slightly ## Footnote This technique helps prevent accidental injection into the parotid gland.
100
What is the primary function of the **Vestibulocochlear nerve (Nerve 8)**?
* Responsible for hearing * Responsible for balance ## Footnote It consists of a vestibular and cochlear component, dealing with balance and head position for the vestibular system and hearing for the cochlear component.
101
How does the **vestibular system** contribute to balance?
* Information helps maintain posture * Sends neurotransmitters to the cochlear * Signal travels to vestibular nuclei ## Footnote The vestibular nuclei consists of four sub-nuclei: inferior, lateral, medial, and superior vestibular nuclei.
102
What are the symptoms of damage to the **vestibulocochlear nerve**?
* Hearing loss * Tinnitus * Dizziness * Loss of balance * Nausea ## Footnote Damage can disrupt hearing and/or vestibular functions.
103
What does **Weber’s test** assess?
* Identifies sensory issues * Identifies conductive problems ## Footnote It uses tuning forks to determine hearing differences between ears.
104
In **Weber’s test**, if sound is less in one ear, what could this indicate?
* Conductive problem on the opposite side * Sensory or neural problem on the tested side ## Footnote The test is performed by placing a tuning fork in the middle of the forehead.
105
What is the expected outcome of **Rinne’s test** in normal patients?
Air conduction (AC) should be better than bone conduction (BC) ## Footnote This test compares the loudness of sound conducted through air versus bone.
106
What does an **absent gag reflex** signify?
Damage to the glossopharyngeal nerve or vagus nerve ## Footnote This can be tested by asking the patient to open their mouth and say 'Ah' to observe symmetry.
107
What sensory functions does the **Glossopharyngeal nerve (Nerve 9)** provide?
* GSS (sensory) – posterior 1/3 of tongue, external ear, middle ear cavity * GVS (sensory) – carotid body and sinus * SVS (sensory) – taste from posterior 1/3 of tongue ## Footnote It also provides motor functions to the parotid gland and stylopharyngeus.
108
What is the role of the **stylopharyngeus** muscle?
Motor function provided by the glossopharyngeal nerve ## Footnote It assists in swallowing and elevating the pharynx.
109
What does **vagus** mean in relation to the **vagus nerve**?
To wander ## Footnote The vagus nerve takes a wandering course from the skull to the abdominal cavity.
110
What types of innervation does the **vagus nerve** supply?
* Sensory * Special sensory * Motor * Parasympathetic ## Footnote It innervates structures of the head, neck, thorax, and abdomen.
111
What is the major role of the **vagus nerve**?
Parasympathetic innervation to the viscera ## Footnote It also provides sensory and motor functions to various regions.
112
List the structures innervated by the **GSS** of the vagus nerve.
* External ear * Larynx * Pharynx ## Footnote GSS stands for General Somatic Sensory.
113
List the structures innervated by the **GVS** of the vagus nerve.
* Larynx * Pharynx ## Footnote GVS stands for General Visceral Sensory.
114
What does **SVS** stand for in relation to the vagus nerve?
Special Visceral Sensory ## Footnote It provides taste from the epiglottis region of the tongue.
115
What does **GVM** stand for in relation to the vagus nerve?
General Visceral Motor ## Footnote It innervates smooth muscles of the pharynx, larynx, and most of the GIT.
116
What does **SVM** stand for in relation to the vagus nerve?
Special Visceral Motor ## Footnote It innervates most muscles of the pharynx and larynx.
117
How is the **vagus nerve** tested?
By absence of gag reflex ## Footnote Stimulating the oropharynx with a long cotton tip tests the efferent limb of the gag reflex.
118
What is the function of the **vagus nerve** during coughing?
Provides motor input to constrict the pharynx ## Footnote This allows for high velocity, forceful coughing.
119
What is another name for the **accessory nerve**?
Spinal accessory nerve ## Footnote It provides motor functions for specific neck and shoulder muscles.
120
What muscles does the **accessory nerve** provide motor functions for?
* Sternocleidomastoid muscle * Trapezius muscles ## Footnote These muscles are involved in head rotation and shoulder shrugging.
121
How can you check the function of the **accessory nerve**?
Ask the patient to rotate their head and shrug their shoulders ## Footnote This should be done both normally and against resistance.
122
What is the primary function of the **hypoglossal nerve**?
Innervates all intrinsic and extrinsic muscles of the tongue except the palatoglossus ## Footnote The palatoglossus is innervated by the vagus nerve.
123
How is the **hypoglossal nerve** examined?
Ask the patient to protrude their tongue and push against the cheek ## Footnote This tests for pressure and weakness.
124
What happens to the tongue when the **hypoglossal nerve** is damaged?
Deviation towards the damaged side on protrusion ## Footnote There may also be muscle wasting or twitches on the affected side.
125
What can cause damage to the **hypoglossal nerve**?
* Penetrating injury * Head or neck malignancies ## Footnote Damage is relatively uncommon.
year 4 CMS
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