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Yr 2 - Control > Neuroanatomy 2 SDL: Brainstem, Cerebellum and Cranial Nerves > Flashcards

Neuroanatomy 2 SDL: Brainstem, Cerebellum and Cranial Nerves Flashcards

1
Q

What are the 5 major subdivisions of the brain?

A
  1. Telencephalon
  2. Diencephalon
  3. Mesencephalon
  4. Metencephalon
  5. Myelencephalon
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2
Q

Which of the five major subdivisions of the brain make up the brainstem?

A
  • Mesencephalon –> midbrain
  • Metencephalon –> pons
  • Myelencephalon –> medulla
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3
Q

On the diagram of the ventral view of the brainstem, below:

  • identify the cranial nerve stumps in yellow and label each nerve with its name and number.
  • label the structures indicated by pointers and their function
A
  • Cerebral peduncles:
    • Connects the remainder of the brainstem to the thalami. They are paired and contain the large white matter tracts that run to and from the cerebrum
      • Motor function
  • Interpeduncular fossa:
    • Separates the two cerebral peduncles
  • Olive:
    • Contains the inferior olivary nucleus, implicated in motor co-ordination
  • Pyramid:
    • Contain the motor fibers that pass from the brain to the medulla oblongata and spinal cord
  • Decussation of pyramids
    • Point at the junction of the medulla and spinal cord where the motor fibres from the medullary pyramids cross the midline.
    • The fibres then continue into the spinal cord primarily as the corticospinal tract.
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4
Q

Brainstem location of the:

  1. Cerebral peduncles
  2. Interpeduncular fossa
  3. Basilar groove
  4. Pyramids
  5. Pyramidal decussation
  6. Olives
A
  1. Midbrain
  2. Midbrain
  3. Pons
  4. Medulla
  5. Junction of medulla and spinal cord
  6. Medulla
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5
Q

What name is given to the ridge that is visible on either side of the ventral midline of the medulla? What fibres is it formed by? What type of information do the fibres carry?

A
  • Medullary pyramids
  • Accumulation of descending nerve fibres
  • Motor information
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6
Q

What does decussate mean?

A

Shaped like an X

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7
Q

Where do most of the descending fibres that make up the medullary pyramids cross?

A

Decussate the midline of the CNS at the caudal end of the medulla –> decussation of pyramids

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8
Q

What structure does the decussation of pyramids partially obliterate?

A

The anterior median fissure

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9
Q

Label the structures on the following dorsal view of a brainstem. What is their function?

A
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10
Q

Brainstem location

  1. Gracile tubercle + gracile fascicle
  2. Cuneate tubercle + cuneate fascicle
  3. Inferior cerebellar peduncle
  4. Middle cerebellar peduncle
  5. Superior cerebellar peduncle
  6. Inferior colliculus
  7. Superior colliculus
A
  1. Posterior side of the closed medulla at the floor of the fourth ventricle
  2. It lies lateral to the gracile tubercle/fascicle in the medulla
  3. Medulla
  4. Connect the cerebellum to the pons
  5. Junction of pons and midbrain
  6. Midbrain
  7. Posterior midbrain
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11
Q

In which region(s) of the brainstem is the central canal expanded to form the fourth ventricle?

A

junction between the pons and medulla oblongata.

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12
Q

What are the distinguishing features of the ventral surface of the medulla oblongata?

A
  • Pyramids
  • Olives
  • Anterior median fissure separating the pyramids
  • Anterolateral sulcus
  • Posterolateral sulcus
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13
Q

What are the pyramids of the medulla? What are they separated by?

A
  • Two pyramids - bulges of white matter
  • Separated by anterior median fissure.
  • Contain descending fibres for motor control.
  • Interrupted at the decussation of the pyramids.
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14
Q

What structure is located lateral to the pyramids?

A

Olives

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15
Q

What separates the olives and the pyramids?

A

The anterolateral sulcus

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16
Q

Which sulcus is found dorsal to the olives? Which cranial nerves emerge here?

A

The posterolateral sulcus - CN X and CN IX emerge here

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17
Q

Which cranial nerves emerge at the anterolateral sulcus?

A

CN XII

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18
Q

What are the distinguishing features of the ventral surface of the pons?

A
  • Cerebellopontine angle
  • Pontomedullary junction
  • Midline ‘basilar’ groove for basilar artery
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19
Q

What is the cerebellopontine angle? Which cranial nerves emerge here?

A

Located between the cerebellum and the pons - CN VII and CN VIII emerge here

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20
Q

What is the pontomedullary junction? Which cranial nerves emerge here?

A

Between the lower border of the pons and the superior border of the medulla - CN VI emerges here (straight, travelling anteriorly)

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21
Q

Where does CN V emerge from?

A

Cranial nerve V: trigeminal – originates from the lateral aspect of mid pon

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22
Q

What are the distinguishing features of the ventral surface of the midbrain?

A
  • Cerebral peduncles
  • Interpeduncular fossa
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23
Q

What are the cerebral peduncles?

A
  • Connect to the cerebrum
  • 2 of them –> crus cerebri
  • Contain descending and ascending fibres
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24
Q

What is found between the 2 cerebral peduncles?

A

Interpeduncular fossa

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25
Q

What cranial nerve emerges from the interpeduncular fossa?

A

CN III

(CN IV also here but moves from dorsal aspect and loops around to ventral aspect)

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26
Q

What shape is the derivative of the central canal of the neural tube at each level of the brainstem?

A
  • Cerebral aqueduct drains CSF from 3rd to the 4th ventricle, spanning pons and open medulla until it becomes the central canal, continuous with the spinal cord.
    • Obex is where the central canal opens into the fourth ventricle
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27
Q

Where does the central canal open into the 4th ventricle?

A

Obex

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28
Q

The following outlines are transverse sections through different brainstem levels. What brainstem levels are these?

What is their ascending order (including E from the next page)

A

A: Caudal pons

B: Midbrain

C: Open/rostral medulla

D: Rostral pons

E, C, A, D, B

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29
Q

This outline is a transverse sectiona through which brainstem level?

A

E

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30
Q

What is the cerebellum primarily involved in?

A

Primarily involved in the coordination of movement, and in the maintenance of balance and posture

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31
Q

Where is the cerebellum found?

A

It is found below the occipital lobes of the telencephalon, separated from it by the tentorium cerebelli. Located posterior to the brainstem.

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32
Q

how is the cerebellum connected to the brainstem?

A

Via three paired cerebellar peduncles.

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33
Q

On the diagram below, label the structures of the cerebellum (superior and ventral views).

A
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34
Q

Are “peduncles” white matter or grey matter structures?

A

White matter

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35
Q

To which region of the brainstem does each cerebellar peduncle connect?

A

Midbrain

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36
Q
  • Which vessels provide the arterial supply to the cerebellum?
  • Are they part of the anterior system of vessels (internal carotid system and its branches) or part of the posterior system (vertebral-basilar system and its branches) to the brain?
A

The cerebellum is mainly supplied by the following three long cerebellar arteries arising from either the vertebral or basilar artery:

  • the posterior inferior cerebellar artery (PICA)
  • the superior cerebellar artery (SCA)
  • the anterior inferior cerebellar artery (AICA).

Part of the posterior system (vertebral-basilar system and its branches)

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37
Q

List the major functions of the cerebellum.

A
  • Receives information from the sensory systems, the spinal cord, and other parts of the brain and then regulates motor movements.
  • Coordinates voluntary movements such as posture, balance, coordination, and speech, resulting in smooth and balanced muscular activity.
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38
Q

Patients with cerebellar damage may display abnormal signs including past-pointing, intention tremor and dysdiadochokinesis.

What do each of these terms mean?

A
  • Past pointing: The inability to place a finger or some other part of the body accurately on a selected point
  • Intention tremor: Produced with purposeful movement toward a target, such as lifting a finger to touch the nose.
  • Inability to execute rapidly alternating movements, particularly of the limbs e.g. pronating and supinating the forearm
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39
Q

How can dysdiadochokinesis be demonstrated at clinical examination?

A

by asking the patient to pronate and supinate an arm at speed, with a tap on the opposite forearm at the extremes of movement.

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40
Q

How can intention tremor be clinically examined?

A

In a finger-to-nose test, a physician has the individual touch their nose with their finger while monitoring for irregularity in timing and control of the movement.

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41
Q

How can past pointing be clinically examined?

A

a subject is asked to point at an object with eyes open and then closed first after rotation in a chair to the right and then to the left and which indicates an abnormality if the subject does not past-point in the direction of rotation.

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42
Q

What can lesions of the brainstem (e.g. tumour, haemorrhage, thrombosis) commonly damage?

A

not only the ascending and descending pathways running through the brainstem but also the cranial nerves at the level of the lesion

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43
Q

Which cranial nerves attach to the midbrain?

A
  • CN III oculomotor
  • CN IV trochlear
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44
Q

Which cranial nerves attach to the pons?

A
  • CN V trigeminal
  • CN VI abducens
  • CN VII facial
  • CN VIII vestibulocochlear
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45
Q

Which cranial nerves attach to the medulla oblongata?

A
  • CN IX glossopharyngeal
  • CN X vagus
  • CN XI spinal accessory
  • CN XII hypoglossal
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46
Q

Which cranial nerve(s) emerge(s) from the cerebellopontine angle?

A
  • CN VII facial
  • CN VIII vestibulocochlear
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47
Q

Which cranial nerve(s) emerge(s) from the interpeduncular fossa?

A

CN III oculomotor

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48
Q

Which cranial nerve(s) emerge(s) immediately lateral to the medullary pyramid?

A

CN XII hypoglossal

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49
Q

Which cranial nerve(s) emerge(s) lateral to the olive?

A
  • CN IX glossopharyngeal
  • CN X vagus
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50
Q

Which cranial nerve(s) emerge(s) from the dorsal surface of the brainstem?

A
  • CN IV trochlear
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51
Q

The paired structures on the inferior surface of the brain - the olfactory bulbs and tracts - are in fact CNS structures, which receive information from the true olfactory nerves.

Where are the true olfactory nerves found? How do they enter the cranial cavity?

A
  • Nasal epithelium
  • Enter cranial cavity via cribriform plate of ethmoid bone
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52
Q

Which nerve nerve is most commonly damaged as a result of head injury? Suggest the mechanism by which such damage occurs.

A

Olfactory nerve fibres pass through a honeycomb-like bone structure known as the cribriform plate as they travel from the nose to the brain. These nerve fibres are at risk of being crushed or severed when the force of a head injury causes the brain to collide violently with the skull.

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53
Q

What is consequence of olfactory nerve damage?

A

Anosmia - loss of smell

54
Q

The optic nerve is also part of the CNS. What is it formed from?

A

An outgrowth of the embryonic diencephalon.

55
Q

What aspects of vision are subserved by the optic nerve, and how are these examined at the bedside or in a clinic?

A
  • To transfer visual information from the retina in your eye to the visual centers of your brain
  • ?
56
Q

Which nerves supply the muscles that move the eye?

A

CN III, CN IV and CN VI

57
Q

Oculomotor nerve:

  • Braimstem location?
  • Skull foramina?
A
  • Interpeduncular fossa (midbrain)
  • Superior orbital fissure
58
Q

Trochlear nerve:

  • Braimstem location?
  • Skull foramina?
A
  • Dorsal brainstem, just below inferior colliculus
  • Superior orbital fissure
59
Q

Abducens nerve:

  • Braimstem location?
  • Skull foramina?
A
  • Pontomedullary junction
  • Superior orbital fissure
60
Q

What type of nerve is the trigeminal?

A

a large mixed nerve (i.e. it contains motor and sensory fibres)

61
Q

What do the sensory components of the divisons of the trigeminal nerve supply?

A

the skin, teeth and mucous membranes of the face plus the anterior scalp and the dura.

62
Q

What do the motor components of the divisons of the trigeminal nerve supply?

A
  • The four main muscles of mastication, plus several others involved in swallowing
  • The tensor tympani muscle which dampens the amplitude of vibration of the tympanic membrane (eardrum).
63
Q

Numerous autonomic fibres also pass through the trigeminal nerve to how many autonomic ganglia of the head?

A

3 out of 4

64
Q

Where are the cell bodies of (most of) the trigeminal sensory fibres located?

A

Most sensory fibers in the trigeminal nerve have their cell bodies in the trigeminal ganglion. This is located in the lateral wall of the cavernous sinus in a depression of the temporal bone, immediately lateral to the pituitary gland.

65
Q

Through which foramina do the three divisions of the trigeminal nerve exit the cranial cavity?

A

V1: Superior orbital fissure

V2: Foramen rotundum

V3: Foramen ovale

66
Q

Each division of the trigeminal nerve has several branches that carry either sensory, motor or autonomic fibres.

Some of these have been highlighted in the diagram below, where the trigeminal ganglion (TG) is coloured yellow, V1 is shown in red, V2 in blue and V3 in green. The names of the 4 pairs of autonomic ganglia are listed in the box (bottom right).

A
67
Q

Sensory innervation of face via branches of trigeminal nerve

A
68
Q

How would you test the functioning of the sensory component of the trigeminal nerve?

A

Lightly touch the face with a piece of cotton wool followed by a blunt pin in three places on each side of the face:

Around the jawline.

On the cheek and.

On the forehead.

69
Q

What are the 2 reflexes associated with the trigeminal nerve? Are any other cranial nerves involved in these 2 reflexes?

A
  1. Corneal reflex - the involuntary blinking of the eyelids –> also involves CN VII (facial)
  2. Jawjerk reflex
70
Q

What is trigeminal neuralgia?

A

Trigeminal neuralgia is a chronic pain condition that affects the trigeminal nerve, which carries sensation from your face to your brain. If you have trigeminal neuralgia, even mild stimulation of your face — such as from brushing your teeth or putting on makeup — may trigger a jolt of excruciating pain.

71
Q

The motor fibres in the trigeminal nerve innervate the muscles of mastication. Name the 4 muscles of mastication.

how is test the functioning of the motor fibres of the trigeminal nerve tested?

A
  1. Masseter
  2. Temporalis
  3. Medial pterygoid
  4. Lateral pterygoid

Trigeminal motor function is tested by palpating the masseter muscles while the patient clenches the teeth and by asking the patient to open the mouth against resistance.

72
Q

If a pterygoid muscle is weak, what side does the jaw deviate to?

A

The affected side

73
Q

Which division of the trigeminal nerve innervates the muscles of mastication?

A

CN V3 (mandibular branch of trigeminal)

74
Q

In a patient with unilateral damage to the right motor root of the trigeminal, what side would the jaw deviate to when opened against resistance?

A

The jaw will deviate towards the lesion –> This direction of the mandible is due to the action of normal pterygoids on the opposite side.

75
Q

What type of nerve is the facial nerve?

A

mixed nerve (motor and sensory)

76
Q

How do the motor fibres of the facial nerve leave the brainstem?

A
  • The motor fibres to the muscles of facial expression and to the stapedius muscle leave the brainstem in the large motor root of the facial nerve.
  • All other fibres leave the brainstem in a much smaller bundle, called the nervus intermedius.
77
Q

What are the sensory functions of the facial nerve?

A
  • A small area around the concha of the external ear.
  • Special Sensory – provides special taste sensation to the anterior 2/3 of the tongue via the chorda tympani
78
Q

Where are the cell bodies of the sensory fibres running in the facial nerve located?

A

The cell bodies for the afferent nerves are found in the geniculate ganglion for taste sensation.

79
Q

What are the parasympathetic functions of the facial nerve?

A

Supplies many of the glands of the head and neck, including:

  • Submandibular salivary glands
  • Sublingual salivary glands
80
Q

The course of the facial nerve is very complex.

  • Where does it enter the cranium?
  • Where does it leave the cranium?
A
  • Enters via internal acoustic meatus
  • Exits via stylomastoid foramen
81
Q

On the following diagram:

  • Label the internal acoustic meatus and the stylomastoid foramen.
  • Label the branch to stapedius, chorda tympani and greater petrosal nerve.
  • Label the geniculate ganglion and the trigeminal ganglion and pterygopalatine ganglion.
  • Name the branches of the facial nerve labelled T, Z, B, M and C.
A
  • Branches:
    • Temporal
    • Zygomatic
    • Buccal
    • Marginal Mandibular
    • Cervical
82
Q

What is the function of the nerve fibres making up the chorda tympani?

A
  • special sensory fibres to the anterior 2/3 tongue
  • parasympathetic fibres to the submandibular and sublingual glands.
83
Q

The chorda tympani carries fibres between the facial nerve and which other nerve? Why?

A

The chorda tympani ‘hitchhikes’ with the lingual nerve. The parasympathetic fibres of the chorda tympani stay with the lingual nerve, but the main body of the nerve leaves to innervate the anterior 2/3 of the tongue.

84
Q

What is the function of the facial nerve fibres running in the greater petrosal nerve?

A

The parasympathetic fibres of the facial nerve are carried by the greater petrosal and chorda tympani branches.

Greater petrosal nerve – parasympathetic fibres to mucous glands and lacrimal gland.

85
Q

How are motor functions of the facial nerve tested? The actions of which muscles are being tested in each case?

A

By asking the patient to:

  • Raise their eyebrows –> occipitofrontalis
  • Screw up their eyes –> orbicularis oculi
  • Purse their lips –> orbicularis oris
  • Show their teeth –> buccinator
86
Q

What is Bell’s palsy?

A

Patients with a Bell’s Palsy will present with varying severity of painless unilateral lower motor neuron (LMN) weakness of the facial muscles

87
Q

How would you tell the difference between someone who has ipsilateral facial weakness due to Bell’s palsy and someone who has ipsilateral facial weakness due to a stroke?

A

Have the patient attempt to raise both eyebrows as if surprised. Then have the patient smile.

  • If they cannot raise their eyebrows and cannot move the lower portion of their face they have Bell’s palsy and should be given steroids +/- antivirals.
  • If the lower portion of the face is paralysed but the eyebrows rise symmetrically, then you have to be concerned for a stroke
88
Q

Damage to the facial nerve may lead to hyperacusis.

  • What is this?
  • Why does it result from a facial nerve lesion?
A
  • Noise sensitivity - Hyperacusis is when everyday sounds seem much louder than they should.
  • Loss of the ear’s protective stapedial reflex –> stapedius innervated by facial nerve
    • The stapedius dampens the vibrations of the stapes by pulling on the neck of that bone.
    • As one of the muscles involved in the acoustic reflex it prevents excess movement of the stapes, helping to control the amplitude of sound waves from the general external environment to the inner ear.
89
Q

What type of nerve is CN VIII?

A

Vestibulocochlear - sensory

90
Q

How can hearing be tested at bedside?

A

Tuning forks are often used to test at chosen frequencies. A variety of other methods (whisper, rubbed fingers, ticking watch, and so forth) can be used to quantify hearing using readily accessible sources of noise.

91
Q

What is an acoustic neuroma?

A
  • A tumour on the vestibulocochlear nerve adjacent to its attachment to the brainstem (from inner ear to brain)
    *
92
Q

As an acoustic neuroma grows, other cranial nerves may also show signs of damage as they become compressed.

  • Which cranial nerves are likely to be compressed as the tumour enlarges?
  • What signs and symptoms would the patient show?
A
  • Trigeminal nerve
  • The symptoms caused by an acoustic neuroma follow the size and growth of the tumor:
    • Hhearing loss in the affected ear, tinnitus
    • Unsteadiness, dizziness
    • As the tumor expands, hearing loss may worsen, facial weakness may occur, and balance problems (disequilibrium) may occur.
    • Large tumors can compress the brainstem (causing imbalance) and the trigeminal nerve (causing facial numbness).
    • As brainstem compression becomes severe, the fourth ventricle collapses and hydrocephalus results, causing persistent headache and visual problems.
93
Q

Which cranial nerves, together, provide both sensory and motor supply to the palate, pharynx and larynx?

A

the glossopharyngeal and vagus nerves

94
Q

What do the terms dysphagia, dysphonia and dysarthria mean?

All three of the conditions above may occur due to cranial nerve damage. List the cranial nerves that may be involved in each case.

A
  • Dysphagia: swallowing difficulties
  • Dysphonia: abnormal voice
  • Dysarthria: difficulty speaking caused by problems controlling the muscles used in speech

Dysphagia: facial nerve (CN VII), glossopharyngeal nerve (CN IX), vagus nerve (CN X), and hypoglossal nerve (CN XII) –> but mainly pharyngeal plexus (CN X and CN IX)

Dysphonia: recurrent laryngeal branch of vagus nerve

Dysarthria: cranial nerves V, VII, IX, X and XII

95
Q

What is the gag reflex? Why is it important?

A
  • The gag reflex, also called the pharyngeal reflex, is a contraction of the throat that happens when something touches the roof of your mouth, the back of your tongue or throat, or the area around your tonsils.
  • This reflexive action helps to prevent choking and keeps us from swallowing potentially harmful substances
96
Q

What type of nerve is glossopharyngeal?

A

CN IX - largely sensory

97
Q

Function of CN IX?

A
  • Is largely sensory, carrying general sensory information from the posterior 1/3rd of the tongue and the oropharynx.
  • Special sensory: Provides taste sensation to the posterior 1/3 of the tongue
98
Q

The glossopharyngeal nerve also has a parasympathetic component. What does this supply?

A

Provides parasympathetic innervation to the parotid gland.

99
Q

What are the functions of the vagus nerve?

  • Motor
  • Parasympathetic
  • Sensory
  • Special sensory
A
  • Motor: motor innervation to the majority of the muscles of the pharynx, soft palate and larynx via the recurrent laryngeal
  • Parasympathetic: smooth muscle of the trachea, bronchi and gastro-intestinal tract and regulates heart rhythm.
  • Sensory:
    • Innervates the skin of the external acoustic meatus and the internal surfaces of the laryngopharynx and larynx.
    • Provides visceral sensation to the heart and abdominal viscera.
  • Special sensory: Provides taste sensation to the epiglottis and root of the tongue.
100
Q

The functioning of the vagus can be tested by asking the patient to say “ahh” and observing the movements of the soft palate.

  • What normally happens?
  • What would happen if you performed this test on a patient with unilateral nerve damage?
    • What other problems would this patient experience?
A

The vagus nerve innervates the muscles that elevate the soft palate (pull the uvula up)

  • Using a tongue depressor to visual the palate and posterior pharyngeal wall –> The soft palate should move upwards centrally
  • Deviation of uvula towards the unaffected area
  • Other symptoms:
    • Hoarse voice
    • Dysphagia
101
Q

What are hthe 2 parts of the accessory nerve?

A

A cranial and a spinal part

102
Q

Describe course of spinal accessory nerve

A
  • Formed from rootlets that leave the upper segments of the cervical cord
  • The spinal part runs into the cranial cavity through the foramen magnum, briefly joins the cranial root of the accessory nerve to travel through the jugular foramen, then separates off and runs to supply the sternocleidomastoid and trapezius muscles.
103
Q

How would you test the functioning of the spinal root of the accessory nerve?

A
  • Asking the patient to rotate their head and shrug their shoulders, both normally and against resistance.
  • Simply observing the patient may also reveal signs of muscle wasting in the sternocleidomastoid and trapezius in cases of long-standing nerve damage.
104
Q

Where is the spinal accessory nerve particularly at risk of damage?

A

Takes a long and superficial course is posterior cervical neck (posterior triangle of neck)

105
Q

What type of nerve is CN XII? Function?

A

The hypoglossal nerve is purely motor - supplies the intrinsic and extrinsic muscles of the tongue

106
Q

What are normal tongue movements necessary for?

A

articulation, chewing and the initiation of swallowing.

107
Q

How would you assess the functioning of the hypoglossal nerve?

A

Ask patient to protrude tongue

108
Q

What would you deduce if a patient’s tongue deviated to one side when protruded?

A

Hypoglossal lesion - Tongue deviates towards side of lesion

109
Q

What other changes in the tongue might you observe in a patient with a hypoglossal nerve lesion?

A

Muscle wasting of tongue muscles

110
Q

How many autonomic ganglia of the head and neck are there? What are they?

A

4:

  • pterygopalatine
  • ciliary
  • otic
  • submandibular
111
Q

What is an autonomic ganglion?

A
  • Receives both parasympathetic and sympathetic inputs
  • A collection of cell bodies within the peripheral nervous system.
    • Is the site where pre-synaptic and post-synaptic neurons join.
112
Q

Are the autonomic ganglia within the head para or sympathetic?

A
  • All the autonomic ganglia within the head are sites where pre- and post-synaptic parasympathetic fibres synapse
  • Sympathetic fibres are present in these ganglia, but they pass through without synapsing
113
Q

Where does the pterygopalatine ganglia receive parasympathetic fibres from? What does it supply?

A
  • Receives parasympathetic fibres from the facial nerve
  • Supplies the lacrimal glands, palatine glands and mucosa of the nasal cavity.
114
Q

Where does the otic ganglia receive parasympathetic fibres from? What does it supply?

A
  • The glossopharyngeal nerve
  • Supplies the parotid gland
115
Q

Where does the submandibular ganglia receive parasympathetic fibres from? What does it supply?

A
  • receives parasympathetic fibres from the facial nerve
  • supplies the submandibular and sublingual glands.
116
Q

Which cranial nerves are involved in the pupillary light reflex?

A

CN II, CN III

117
Q

Which cranial nerves are involved in the corneal reflex?

A

CN VII and CN V1

118
Q

Which cranial nerves are involved in the gag reflex?

A
  • The afferent limb of the reflex is supplied by the glossopharyngeal nerve (cranial nerve IX)
  • The efferent limb is supplied by the vagus nerve (cranial nerve X)
119
Q

What controls pupillary constriction?

A
  • Parasympathetic innervation
  • Circular muscle called sphincter pupillae
120
Q

How can you test pupillary light reflex?

A

Shine light between both pupils and assess response

121
Q

What controls pupillary dilation?

A
  • Sympathetic innervation
  • Controlled by dilator pupillae
122
Q

How is the corneal reflex tested?

A

involuntary blinking of the eyelids elicited by stimulation of the cornea (such as by touching or by a foreign body)

123
Q

How is the gag reflex tested?

A

Touching each side of the pharynx with the sterile tongue depressor tests the pharyngeal “gag” reflex

124
Q

Which TWO visual reflexes would be absent in a patient with unilateral oculomotor nerve damage? Which other cranial nerve is involved in these reflexes?

A
  • Pupillary light reflex
  • ?
125
Q

List two possible causes of oculomotor nerve damage.

A
  1. Raised intracranial pressure (compresses the nerve against the temporal bone).
  2. Cavernous sinus infection or trauma.
126
Q

A patient presenting with the following appearance could have either Horner’s syndrome on the right or an early right oculomotor palsy.

How would you distinguish between the two?

A

Horner’s:

  • Ptosis
  • Anhidrosis
  • Miosis (constriction of pupil)

Oculomotor nerve palsy:

  • Ptosis
  • Mydriasis (dilation of pupil of eye)
  • Down and out
127
Q

What is the method of testing every cranial nerve during routine neurological examination?

A

Look up

128
Q

Which cranial nerves are not easily tested during routine examination?

A
  • Vestibular part of CN VIII
  • Components other than sensory of CN IX
  • Sensory part of CN X
129
Q

complete the table below

A

?

130
Q

label the superior view of the skull base, bones, and its foramina, including the structures which pass through them.

A

Yr 2 - Control (71 decks)

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