Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Neurology > Cranial Nerves > Flashcards

Cranial Nerves Flashcards

1
Q

Define Neurology

A

Science of studying the etiology, pathogens, pathology, clinical manifestation, treatment, prognosis and prevention of nervous system diseases and muscular diseases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

List the cranial nerves in order

A
  1. Olfactory nerve
  2. Optic nerve
  3. Oculomotor nerve
  4. Trochlear nerve
  5. Trigeminal nerve
  6. Abducens nerve
  7. Facial nerve
  8. Acoustic nerve
  9. Glossopharyngeal nerve
  10. Vagus nerve
  11. Accessory nerve
  12. Hypoglossal nerve
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Describe the anatomy and pathway of the optic nerve

A

Retina(rods, cones) —> ganglion cells —> optic nerve —> optic chiasm (nasal half fibres cross, temporal half fibres uncross) —> optic tract —> lateral geniculate body —> posterior limb of the internal capsule —> optic radiation —> occipital (cal caribe) cortex (visual centre)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

List the clinical findings for visual and visual field defects for the optic nerve (different locations of the lesions)

A
  1. Optic nerve: total blindness of the Ipsilateral eye
  2. Optic chiasm: (such as primary tumour): bitemporal hemianopsia
  3. Perichiasmal centre: (calcified ICA): ipsilateral nasal hemianopsia
  4. Optic tract: contra lateral total homonymous hemianopsia
    Optic radiation:
    5.complete lesion can cause contra lateral homonymous hemianopsia
  5. Lower portion cause contra lateral superior quadrantanopsia
  6. ## Upper portion cause contralateral inferior quadrantanopsia
  7. Occipital lobe: produces contralateral homonymous hemianopsia with macular sparing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is meant by “macular sparring”

A

Visual field in the central portion of the hemianopsia side is preserved and the light reflex in the same side still exists. Macular sparring is a characteristic of central hemianopsia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Which 3 nerves move the eye?

A
  • Oculomotor
  • Trochlear
  • Abducens
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Where is the nuclei of the III cranial located and what is the function?

A

Group of nuclei located in the midbrain.
There are 5 subnuclei that correspond to different muscles that are responsible for different functions of the eye

Levator palpebrae m: opens the eye
Superior rectus m: moves the eye up
Medial rectus muscle: moves the eye medically
Inferior rectus muscle: moves the eye downward
Inferior oblique muscle: moves the eye up and out

E-W:
Sphincter of iris: constricts pupil
Ciliary muscle: thickens the lens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Where is the nuclei of the IV cranial nerve locates and what is the function

A

Located in the midbrain
Superior oblique muscle: moves eye down and out

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Where is the nuclei of the VI cranial nerve locates and what is its function?

A

Located in the pons
Lateral rectus muscle: moves eye outwards

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Define the following clinical terms:
1. Intraocular muscles
2. Extraocular muscles
3. Diplopia (double vision)
4. Accommodation reflex

A
  1. Sphincter muscle of iris, ciliary muscle, dilator muscle of iris (involuntary muscles)
  2. Levator palpebrae muscle, superior recuts muscle, medical rectus muscle, medial rectus muscle, inferior rectus muscle, inferior oblique muscle, superior oblique muscles, lateral rectus muscle (voluntary muscles)
  3. When one extraocular muscle is paralysed, the eye can not move towards the direction that the paralysed muscles functions, and the patient will see two separate images of the same object in visual space when both eyes are viewing
  4. When both eyes follow an object that is brought to from a distance up close to the nose, both eyes converge with a constriction of pupils
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does light reflex refer to?

A

Constriction of the pupil when light is thrown at the retina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the pathway of the light reflex?

A

Light —> retina —> optic nerve —> optic chiasm —> midbrain —> E-W nuclei —> Oculomotor nerve —> ciliary ganglion —> postganglionic fibres —> sphincter of iris

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Comment on the diameter of the pupil
- normal
- constriction
- dilation

A

Normal: 2-4mm
Constriction: <2mm (miosis)
Dilation: >5mm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is meant by “Horner’s sign”

A

When cervical sympathetic nerve is injured
Affected side shows:
-miosis
- ptosis (narrowed palpebral fissure)
-enopthtalmos (posterior displacement of the eye in the orbit)
-absence of sweating of the face (anhydrosis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

List the clinical types of peripheral ophthalmoplegia

A

A. Peripheral ophthalmoplegia: lesion of Oculomotor nerves (not nuclei)
1. Paralysis of CN III: ptosis or dropping of the upper eyelid, external squint, difficulty moving eye up, down, in, diplopia, dilation of the pupil, loss of light and accommodation reflexes
2. Paralysis of CN IV: paralysis of superior oblique muscle causes diplopia on looking downward. Patient typically has difficulty descending stairs
3. Paralysis of CN VI: internal strabismus, eye cannot move outward, diplopia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe the location, characteristics and clinical manifestations of nuclear ophthalmoplegia

A

Location: nucleus of III (midbrain), IV (midbrain), VI (pons)
Characteristics: besides Oculomotor nucleus, often involves the nearby structures (pyramidal tract)
Clinical manifestation: typically crossed hemiplegia, such as Webber syndrome

**inability to perform lateral conjugate gaze

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Describe the location and clinical manifestations of supranuclear ophthalmoplegia

A

Location of lesion: conjugate gaze centre (posterior portion of middle frontal gyrus, area 8), which moves both eyes simultaneously and horizontally to the opposite side
Clinical manifestation: causes paralysis of the conjugate gaze to the opposite side.
Destructive lesions produce conjugate deviation of the eyes to the side of the lesion, irritation lesions produce conjugate deviation of the eyes to the opposite side of the lesion

18
Q

Describe the sensory pathway of the Trigeminal nerve

A

V1: ophthalmic branch
V2: maxillary branch
V3: mandibular branch
V1-V3: Trigeminal semilunar ganglion

Nucleus of main sensory (touch) and nucleus of spinal tract (pain and temperature) —> fibres cross to the opposite of medulla —> Trigeminal lemniscus —> ventroposterior or medial nucleus of the thalamus —> posterior limb of the internal capsule —> post central gyrus

19
Q

What is the corneal reflex

A

Blinking of the eye upon gentle irritation of the cornea with a small piece of absorbent cotton

Pathway—> cornea-(V1)-nucleus of main sensory-facial nerve-orbicular muscle of the eye

20
Q

Describe the motor pathway of the Trigeminal nerve

A

Precentral gyrus —> corticocobulbar tract —> internal capsule —> bilateral Trigeminal motor nuclei (V3) —> muscles of mastication (massater, temporal, internal and external pterygoid)

21
Q

Describe the clinical features when a lesion occurs on one of the branches of the Trigeminal nerve

A

Lesion on V1:
Abnormal sensation (pain, loss of sensation) of the skin supplied by V1 (forehead, eye, nose, temple, meninge, paranasal sinus, part of nasal mucosa), as well as loss of corneal reflex
Lesion on V2:
Abnormal sensation of the skin supplied by V2 (upper jaw, upper teeth, upper lip, cheek, hard palate, maxillary sinus, nasal mucosa)
Lesion on V3:
Abnormal sensation of the skin supplied by V3 (lower jaw, lower teeth, lower lip, bucca, mucosa, tongue, part of the external ear, auditory meatus, meninge), as well as paralysis of the muscles of mastication

22
Q

Describe the anatomy and pathway of the facial nerve

A

Bilateral corticobulbar tract (superior part of facial nucleus) and contralateral corticobulbar tract (inferior part of facial nucleus) —> facial nerve —> internal acoustic meastus —> facial canal—> chords tympani (ant 2/3 of taste of tongue) —> geniculate ganglion —> stylomastoid foramen —> expressive muscles of the face

Expressive muscles of the face:
Upper: frontalis muscle (wrinkles forehead), orbicular muscle of eye (winks or closes eye)
Lower: buccal (smile), orbicular muscle of mouth (shows teeth)

23
Q

Describe the location and clinical manifestations of peripheral facial palsy

A

Location of lesion: facial nucleus or facial nerve
Manifestation:
1. On the affected side:
Wrinkles on forehead becomes flat, palpebral fissure becomes larger, nasolabial sulcus becomes flat, mouth droops and may draw to the other side, loss of taste of the anterior 2/3 of the tongue (when chords tympani affected). The patient has difficulty to: wrinkle their forehead, close or tightly close their eyes, show his teeth and whistle

24
Q

Describe the location and clinical manifestations of central facial palsy

A

Location of lesion: corticobulbar tract
Manifestations:
1. On the contralateral side:
All the peripheral facial palsy signs are present except: wrinkles on forehead doesn’t become flat, palpebral fissure doesn’t become larger. Patient has no difficulty in wrinkling forehead or closing eye.
(Because the inferior part of facial nucleus only receives contralateral corticobulbar tract inner action, but the superior part of facial nucleus receives bilateral corticobulbar tracts innervation)

25
Q

Describe the pathway of the vestibular nerve (pure sensory nerve)

A

Vestibular apparatus in the inner ear (3 semicircular canals) —> vestibular ganglion —> vestibular nerve —> internal acoustic meatus —> group of vestibular nuclei (medial, lateral, superior, spinal) —>
vestibular spinal tract which goes to spinal anterior horn cells
Vestibulocerebellar tract which goes to cerebellum
Medial longitudinal fasciculus which goes to ocularmotor nerves (III, IV, VI)

26
Q

What is the function of the vestibular nerve

A

Feels the position and movement of the head and body in the space and reflectively adjusts the equilibrium of the body

27
Q

What are the clinical findings of the vestibulocochlear nerve

A
  1. Vertigo: a motor hallucination. The patient feels surrounding objects are moving or rotating, with nausea and vomiting
    Type I: peripheral vertigo —> usually. Caused by vestibular apparatus or extracranial vestibular nerve disease. Symptoms are usually serious and last a short time
    Type II: central vertigo —> usually caused by intracranial vestibular nerve, vestibular nucleus or pathway disease. Symptoms are usually slight and last longer
  2. Equilibrium: imbalance of gait, shaking of the body, easy to dump to the affected side (Romberg sign +)
  3. Nystagmus: an involuntary, rhythmic, quick and to-fro eyeball movement
    Types: horizontal, vertical, rotatory
28
Q

What is the pathway of the cochlear nerve

A

Organ of corti —> spinal ganglion in the inner ear —> cochlear nerve —> internal acoustic meatus —> anterior and posterior cochlear nucleus (pons) —> bilateral ascending fibres (lateral lemniscus) —> inferior colliculus —> medial geniculate body —> acoustic radiations —> superior temporal gyrus (acoustic centre)

29
Q

Clinical findings for cochlear nerve

A

Deafness:
1. Nerve deafness: interruption in nerve pathway
2. Conductive deafness: perforation of tympanic membrane
3. Mixed deafness: often seen in old people

Tinnitus:
Subjective and lasting noise caused by an irritative disease in the sound perceiving organ or conductive pathway
Generally, sound perceiving organ disease is high-pitched tone, conductive pathway disease is low-pitched tone

30
Q

Anatomy and physiology of nerves IX and X

A

Motor:
Precentral gyrus —> bilateral corticobulbar tract —> nucleus ambiguous in medulla —>
Glossopharyngeal nerve —> stylopharyngeus muscle (raises pharyngeal vault)
Vagus nerve —> muscles of the pharynx, larynx and soft plate

Sensation:
General sensation in pharynx, pharynx and posterior 1/3 of the tongue
Taste sensation of the posterior 1/3 of tongue

31
Q

Clinical findings for IX and X nerves

A

Unilateral IX and X palsy
1. Hoarseness
2. Dysphagia
3. Loss of sensation in pharynx and larynx
4. Soft plate cannot be raised
5. Deviation of the uvula to the “well” side
6. Loss of gag reflex

32
Q

Describe the anatomy of XI

A

Bilateral corticobulbar tracts —>
1. Ambiguous nucleus (medulla) —> medullary branch —> recurrent laryngeal nerve —> intrinsic muscle of larynx
2. Accessory nucleus (anterior horn of C1-C5) —> spinal branch —> sternocleidomastoid muscle and trapezius muscle

33
Q

List the clinical findings for XI

A

Unilateral accessory nerve paralysis produces
- cannot rotate the head to the “well” side
- cannot shrug affected shoulder
- atrophy of SCM and trapezius muscle
Dropping of the shoulder

34
Q

Describe the pathway of the hypoglossal nerve

A

Contralateral corticobulbar tract —> hypoglossal nucleus (medulla) —> hypoglossal nerve —> hypoglossal canal —> muscles of the tongue

Genioglossus: protrudes the tongue
Hypoglossal muscle: contracts the tongue

35
Q

Describe the peripheral type of hypoglossal nerve palsy

A

Lesion location: hypoglossal nerve or its nucleus
Deviation of the tongue on protrusion to: affected side
Atrophy of the affected side: yes

36
Q

Describe the central type of hypoglossal nerve palsy

A

Lesion location: motor cortex of corticobulbar tract
Deviation of the tongue on protrusion to: well side
Atrophy of the affected side of the tongue: no

37
Q

What is Weber syndrome?

A

Weber syndrome is also called midbrain stroke syndrome or superior alternating hemiplegia that causes ipsilateral 3rd nerve palsy with contralateral hemiparesis

38
Q

List 4 main indications of Weber syndrome

A
  1. eye deviation “down and out”
  2. eyelid droop
  3. pupil dilated and unresponsive
  4. port-wine stain on face (1st and 2nd division of trigeminal nerve)
39
Q

Hemiparesis vs hemiplegia

A

Main difference lies in severity
Hemiparesis is the mild or partial loss of strength on one side of the body whereas hemiplegia is the severe or complete loss of strength on one side of the body

40
Q

What is intranuclear ophthalmoplegia?

A

It is an ocular movement disorder that presents as the inability to perfrom conjugate lateral gaze and hemiplegia due damage to the interneuron between two nuclei of cranial nerves VI and III. This interneuron is called the medial longitudinal fasciculus

41
Q

What is the interneuron between the nuclei of CN VI and CN III called?
What is the name of the disorder called when damaged to this interneuron occurs?

A

Medial longitudinal fasciculus
- intranuclear ophthalmoplegia

Neurology (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions