Cranial nerve exmination

To
CLINICAL ANATOMY OF CRANIAL NERVES

By
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Dr . Giridhar M Kanthi
Prof & Head
Dept of Basic principles
S D M College of Ayurveda. Udupi

8/23/2011 Dr G M Kanthi Prof S D M C A Udupi 1

“ You have I nose & II eyes ”
“ h & ”

I ‐ Olfactory n. & II ‐ Optic n.
I ‐ Olfactory n & II ‐ Optic n


The cranial nerves all exit from the bottom surface of the brain and brainstem

and exit the skull through various holes (foramina) to reach their targets
targets.

Cranial Nerve 1 Smell
Cranial Nerve 2 Vision
Cranial Nerve 3 Eye movement
Cranial Nerve 4
Eye movement
Cranial Nerve 5 Facial sensation
Cranial Nerve 7 Facial movement
Cranial Nerve 8 Hearing and balance
Cranial Nerve 9
C i lN 9 Organs and Taste
O dT t
Cranial Nerve 10 Organs and Taste
Cranial Nerve 11 g
Shoulder shrug & head turn
Cranial Nerve 12 Tongue movement

Cranial Nerves
attachments


Olfactory Nerve C N I

CN II

C N IV
C N IV
C N III
C N V
C N VI
C N VII
C N VII
C N VIII
C N IX
C N X
C N XI C N XII

1. One I ‐ Olfactory
I    On
II   Old 2. Of
2 Of II ‐ Optic

III   Olympus 3. Our III – IV – VI ‐ Extraoculars
IV   Towering 4. Trained
4 T i d III – Oculomotor
V Trigeminal
V   Tops 5. Teacher IV – Trochlear
6. Asked
6 Asked VII
VII ‐ Facial VII ‐
VII Abducent
VI  A
VI A
VII   Finn 7. For VIII ‐ Vestibulocochlear
VIII   And
VIII And 8. A
8 A
IX ‐ Glossopharyngeal,
IX   German 9. Good
X ‐ Vagus
X   Viewed
X Viewed 10. Vehicle
10. Vehicle
XI   Astounding 11. And XI: Accessory
XII   Hops 12. Horse
XII: Hypoglossal
XII H l l


Extraocular muscles

“ LR 6 ‐ SO 4 ‐ Rest 3 "
“ LR 6 SO 4 R 3"

LR 6 Lateral Rectus ‐‐> VI abducens

SO4 Superior Oblique ‐‐> IV Trochlear

Remaining 4 eyeball movers ‐‐> III oculomotor


I ‐ Olfactory
Fore brain
II ‐ Optic
II O ti

III – Oculomotor
Mid brain
Mid b i
IV – Trochlear

V Trigeminal
V Trigeminal
VII ‐ Abducent
Pons
VII ‐ Facial
VIII ‐ Vestibulocochlear

IX Glossopharyngeal,
IX ‐ Glossopharyngeal
X ‐ Vagus
Medulla
XI: Accessory
y
XII: Hypoglossal

Some
I Some (Sensory)
Says
II Say (Sensory)
Marry
III Marry (primarily Motor)
Money
IV Money, (primarily Motor)
But V But (Both)
My VI My (primarily Motor)

Brother VII Brother (Both)

Says VIII Says
VIII Says (Sensory)
IX Big (Both)
Bad
X
X Bras
Bras (Both)
Business
XI Matter (primarily Motor)
Marry
XII More (p
(primarily Motor)
y )
Money


Summary of the Cranial Nerves

I ‐ Smell

II ‐ Vision ‐ Visual acuity, visual fields and ocular function

II, III ‐ Pupillary reactions

III, IV, VI ‐ Extra‐ocular movements, including opening
III IV VI E t l t i l di i

of the eyes & eye movement
of the eyes & eye movement

p
ptosis (III nerve) and pupil reaction to light (II & III nerve)
( ) p p g ( )


Paralysis of ( III ) oculomotor nerve

Results

Partial ptosis

Dilation of pupil

Loss of accommodation

Diplopia

Lateral squint

V ‐ Facial sensation, movements of the

jaw, and corneal reflexes

VII ‐ Facial movements and gustation

VIII ‐ Hearing and balance


IX, X ‐ Swallowing, elevation of the palate, gag reflex and
gustation

V, VII, X, XII ‐ Voice and speech

XI ‐ Shrugging the shoulders and turning the head

XII ‐ Movement and protrusion of tongue
XII M t d t i ft


Olfactory Nerve – Cranial Nerve 1

The olfactory nerve is essentially responsible for the sense of smell.

It courses along the base of the frontal lobes and perforates through

the base of the skull and rests inside the roof of the nose.

Recently, these nerves have received additional interest because of their

potential for involvement in the harvest of naturally existing stem cells.


Olfactory Nerve
Olf N

Olfactory Bulb

Olfactory Tract

Test each nostril with essence bottles

of coffee, vanilla, peppermint.


Evaluate the potency of the nasal passages bilaterally

Inform to close the eyes
Cranial Nerve I
place a small bar of soap near the patent nostril

ask the patient to smell the object

This part of the exam is often omitted

unless their is a reported history suggesting head

trauma or toxic inhalation.
t t i i h l ti

Very little localizing information can be obtained


The olfactory nerve is essentially responsible for the sense of smell.

Gather some items with distinctive smells

(for example, cloves, lemon, chocolate or coffee).

Test each nostril with essence bottles of coffee, vanilla, peppermint.

C. N I. video


Cranial Nerve II

Using an ophthalmoscope,

Observe the optic disc

Retinal vessels a d fovea
e a esse s and o ea

Note the pulsations of the optic vessels

Check for a blurring of the optic disc margin

Change in the optic disc's color form its

normal yellowish orange
y g


The initial change in the ophthalmoscopic examination

in a patient with increased intracranial pressure

is the loss of pulsations of the retinal vessels.

This is followed b bl i of th optic di margin
Thi i f ll d by blurring f the ti disc i

and possibly retinal hemorrhages.
p y g


Cranial Nerve II

Visual acuity by using a

pocket visual acuity chart

Visual acuity

Evaluate the visual fields,

color vision, and optic disc appearance

visual fields

Observe the diameter of the pupils in a dimly
Cranial Nerves II and III
light room.

Shine the penlight light into one eye at a time

and check both the direct and consensual light

responses i each pupil.
in h il

Note the symmetry between the pupils.

Test for pupillary constriction

Note their size and possible asymmetry
asymmetry.


The two circles below represent the vision seen by both eyes. Initially,

both the right and the left optic nerve record and take back to the brain

2 colors – black and yellow.
2 colors – black and yellow

After the fibers cross in the optic chiasm, only the yellow picture from

Each eye is returned to the left occipital lobe

and only the black picture is returned to the right occipital lobe.

Left Eye
Left Eye Right Eye
Right Eye


Ptosis is the lagging of an eyelid.

The ptosis from a III nerve palsy is of greater

severity than the ptosis due to a lesion of the

sympathetic pathway,

Anisocoria is a neurological term indicating

that one pupil is larger than another.


V
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Cranial Nerves III, IV and VI – Oculomotor, Trochlear, Abducent

Eyes movement in all direction without moving the head.

The movement of both eyes in one direction is called a conjugate movements
The movement of both eyes in one direction is called a conjugate movements

The oculomotor nerve is the most diverse.

It is responsible for moving each eye towards the nose, up, down, and

external rotation.
external rotation

Additionally, it is responsible for shrinking the size of the pupil and allow

less light to enter the eye.


A problem with the oculomotor nerve might result in

double vision when looking at near object and cause

trouble when reading.
trouble when reading.

The trochlear nerve is responsible for internal rotation of the eye.

A problem with this nerve often is noticed by the patient as they

have trouble walking down stairs.

abducens nerve is responsible for moving each eye temporally – or

away from the nose. A problem with the sixth nerve results in double
f th A bl ith th i th lt i d bl

vision on looking at distant objects.


2
4
6
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Trigeminal Nerve ‐ Cranial Nerve 5

The trigeminal nerve is one of the largest cranial nerves.

It also has many functions.

The entire sensation from the face, the forehead, the cheeks,

and the jaw are returned to the brain from the three different

divisions of this nerve.



Three different divisions of this nerve.

1. Opthalmic br. ‐ Sensory to Fore head, air sinus, Eyeball (ciliary, eyelids)

side & tip of nose, and lacrimal gland

2. Maxillary br. ‐ Middle cranial fossa, pterygopalatine fossa,

Imfraorbital canal, and Face

3. Mandibular br. ‐ t
3 M dib l b pterygoid, lingual, mylohyoid, and diagastricz
id li l l h id d di ti


Cranial Nerve – V
Test for ‐ Jaw power
Trigeminal
Sensation of face

Corneal and jaw reflexes
Corneal and jaw reflexes

1. Palpate the masseter muscles

2. Note masseter wasting on observation

3. Ask the patient to open their mouth against

resistance applied by the instructor at the base

of the patient's chin.


4. Test gross sensation –

Tell the patient to close their eyes and say "sharp" or

"dull" when they feel an object touch their face
"d ll" h th f l bj t t h th i f

5. Ask the patient to also compare the strength
p p g

of the sensation of both sides

6. Touch the patient above each temple, next

to the nose and on each side of the chin
h d h id f h hi

7. Test the corneal reflex ‐ look for the eye to blink



• Corneal reflex: patient looks up and away.

• Touch cotton wool to other side.

• Look for blink in both eyes, ask if can sense it.

• Repeat other side [tests V sensory, VII motor].

•F i l
Facial sensation: sterile sharp item on forehead, cheek, jaw.
ti t il h it f h d h k j

• Repeat with dull object. Ask to report sharp or dull.

• If abnormal, then temperature [heated/ water‐cooled tuning fork],

light touch [cotton].
light touch [cotton].



• Motor: pt opens mouth, clenches teeth (pterygoids).

• Palpate temporal, masseter muscles as they clench.

• Test jaw jerk:
Test jaw jerk:

 Dr's finger on tip of jaw.

 Grip patellar hammer halfway up shaft and tap Dr's finger lightly.

 Usually nothing happens, or just a slight closure.

 If increased closure, think UMNL, esp pseudobulbar palsy.


Facial Nerve ‐ Cranial Nerve 7

The facial nerve is responsible for moving most of the muscles of the face.

It helps us to smile, raise an eyebrow, wrinkle the forehead, puff our cheeks,

straighten our neck muscles in order to shave, and sometimes even to wiggle

Our ears. Interestingly, enough, the taste from the front 2/3 of the tongue is

transmitted to the brain from the facial nerve and parts of the facial nerve aids

In allowing the salivary glands to secrete their fluid to assist in chewing and

digestion.


Cranial Nerve VII – Facial
1. inspect the face during conversation and

rest, noting any facial asymmetry

2. Drooping, sagging or smoothing of normal
2 D i i hi f l

facial creases.

3. Ask the patient to raise their eyebrows,

smile showing their teeth,

Branches of the facial nerve

"Ten Zombies Bought My Car“

Temporal, Zygomatic, Buccal, Masseteric, Cervical
Temporal Zygomatic Buccal Masseteric Cervical


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Auditory Nerve ‐ Cranial Nerve 8

Another name for the auditory nerve is the vestibulo‐cochlear nerve.

It is so called this because it serves 2 purposes.

The hearing or sound information is transmitted back to the

brain through the cochlear nerve.
b i h h h hl


The balance information is transmitted through the vestibular
g

portion of the nerve.

There is a fairly well known tumor although misnamed

called an Acoustic Neuroma which arises from this nerve.
ll d h h f h

It is misnamed because this commonly benign tumor actually arises from
It is misnamed because this commonly benign tumor actually arises from

the vestibular nerve and is not a nerve tumor as the name implies.

Vestibular test
Vestibular test


Cranial Nerve VIII ‐ Auditory
Rinne's test

The Rinne’s test compares air conduction to

bone conduction.
bone conduction

Perform an otoscopic examination of both

Eardrums to rule out a severe otitis media

Occlusion of the external auditory meatus
Occlusion of the external auditory meatus

Perforation of the tympanic membrane


Cranial Nerve VIII  ‐ Auditory

Assess hearing
A h i

1. By instructing the patient to close their eyes,

Vigorously rub your fingers together very near

to the ear.
to the ear.

2. The sound was the same in both ears, or

louder in a specific ears

3. If there is lateralization or hearing

abnormalities  perform the Rinne and Weber Tests
Weber’s test

The Weber test is a test for lateralization
Th W b t t i t t f l t li ti


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•Dr's hands arms length by each ear of pt.

• Rub one hand's fingers with noise on one side, other hand noiselessly.

• Ask pt. which ear they hear you rubbing.
Ask pt which ear they hear you rubbing

• Repeat with louder intensity, watching for abnormality.

• Weber's test: Lateralization

• 512/ 1024 Hz [256 if deaf] vibrating fork on top of patients head/ forehead.

• "Where do you hear sound coming from?"

• Normal reply is midline.


• Rinne's test: Air vs. Bone Conduction

• 512/ 1024 Hz [256 if deaf] vibrating fork on mastoid behind ear.

Ask when stop hearing it.

• When stop hearing it, move to the patients ear so can hear it.

• Normal: air conduction [ear] better than bone conduction [mastoid].

• If indicated, look at external auditory canals, eardrums.


Cranial Nerves IX and X

The functions of the glossopharyngeal and the vagus nerve

are too many to list. In essence, these two nerves take to and

from the brain information regarding swallowing, taste, voice,

organ function, heart rate, abdominal function, etc.

In fact, vagus means wandering in Latin.
In fact vagus means wandering in Latin


Glossopharyngeal and Vagus Nerve ‐ Cranial Nerve 9,10

The vagus nerve actually starts from the brain and is continuous all

the way through and even reaches the intestines.

Since there are so many functions of this nerve,

the signal from the body also have to be returned to many

parts of the brain through the same nerve as well.


Interestingly, it was discovered that this nerve

could serve as a conduit through which to treat epilepsy – or seizures.

A neurosurgeon can surgically wrap and electrode around this nerve and

connect it to a pacemaker device which can then be used to treat epilepsy
t it t k d i hi h th b d t t t il

in some patients
in some patients


Cranial Nerves IX and X - Glossopharyngeal & Vagus

Soft palate elevation,
Ask the patient to swallow and note any
Deviation & Gag reflex
difficulty doing so.
difficulty doing so

Note the quality and sound of the patient's

voice. Is it hoarse or nasal ?

observe the soft palate, uvula and pharynx.
observe the soft palate uvula and pharynx

The soft palate should rise symmetrically,

the uvula should remain midline


•Pt says "Ah": symmetrical soft palate movement.
Pt "Ah" t i l ft l t t

Gag reflex [sensory IX, motor X]:
Gag reflex [sensory IX motor X]:

• Stimulate back of throat each side.
Stimulate back of throat each side.

• Normal to gag each time


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Accessory Nerve ‐ Cranial Nerve 11

The accessory nerve is responsible for turning the head,

nodding yes and no, and shrugging the shoulders. Specifically,

it controls the muscles called the sternocleidomastoid and the trapezius.

Since this nerve controls head turning and is a cranial nerve – as

opposed to a spinal nerve, the motion of turning the head is

typically preserved in patients who injure their spinal cords


Cranial Nerve XI - Accessory

Shoulder elevation & turning of neck

with head (trapezius and sternomastoid)

Evaluated by looking for wasting of the

trapezius muscles by observing
i l b b i

Ask the patient to turn their head to

the side as strongly as they possibly
h d l h bl


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Hypoglossal Nerve ‐ Cranial Nerve 12
Hypoglossal Nerve ‐ Cranial Nerve 12

The hypoglossal nerve is responsible for the complex movements of the
The hypoglossal nerve is responsible for the complex movements of the

tongue. There is some help from the vagus nerve but three of the four

main tongue muscles are controlled from the hypoglossal nerve.


Cranial Nerve XII – Hypoglossal
yp g

The hypoglossal nerve controls the intrinsic

musculature of the tongue
l t f th t

Tongue function; wasting / fasciculation


Cranial Nerve XII – Hypoglossal

Note is their deviations of the tongue from midline,

Note complete lack of ability to protrude the tongue

Note is there the tongue will be protruded
g p

from the mouth and remain midline.


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Dr . Giridhar M Kanthi. B S A M; DHA; Ph.D

Prof & Head
Dept of Basic principles

S D M College of Ayurveda. Udupi. 574 118
Karanataka
Residence – Hudco Colony
L I G 39
Manipal – 576 104

Cell – 9448888378
Land line - 08202570417

E mail – girisha_k @yahoo.com

girishakanthi@gmail.com

giridhar@webduniya.com
giridhar@webduniya com


Cranial nerve exmination

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