Cranial nerves I through XII were assessed using various tests. CN I (olfactory) was tested by having the patient smell different odors. CN II (optic) assessment included visual acuity, visual fields, and ophthalmoscopy. CN III, IV, and VI were evaluated using light reflexes, accommodation, and eye movements. Sensory and motor functions of CN V (trigeminal) were assessed using touch, temperature, and jaw movement tests. Facial expression was used to examine CN VII (facial) motor skills. Hearing was roughly tested for CN VIII (acoustic). Swallowing and palate movement checked CN IX and X. Shoulder shrugging assessed CN XI (

1. CRANIAL NERVES
Assessment
C.R.PRAVEEN
KUMAR
ASSISTANT
PROFESSOR

2. CN I – OLFACTORY (SENSORY)
Not often checked –
impairment usually due to
other causes (allergies,
colds)
Impairment will also lead
to decreased taste
Check each nostril
independently with
patient’s eyes closed
Use non-toxic substances
such as
 Coffee
 Tobacco
 Mild soap (Ivory)
 Cloves

3. CN II – OPTIC (SENSORY)
Three tests
1. Visual acuity (sharpness or keenness)
2. Visual fields (peripheral vision)
3. Ophthalmoscope (internal eye inspection of optic
fundus, where CNII joins the eye)

4. CN II – OPTIC: CHECKING VISUAL ACUITY
Snellen chart may
be used for greater
accuracy
Simple acuity test
 Patient covers one eye
at a time
 Hold up fingers and
ask how many he/she
sees
 Or simply read a
newspaper at arm’s
length

5. CN II – OPTIC: CHECKING
VISUAL FIELDS
Method called confrontation
 Sit 2-3 feet from patient, your left eye
aligned with patient’s right
 Your eye acts as control, so you need
good peripheral vision!
 You close or cover your eye aligned with
patient’s eye
 Holding up your index finger, mid-
distance between the patient and
yourself, just beyond your own
peripheral field, wiggle your finger as
you slowly bring it into the visual field.
 Ask the patient to tell you when he first
sees your finger. It should be at about
the same time that you see it.
 Repeat the test to cover the entire visual
field for each eye, which is to test at
each of the six even-numbered
positions on a clock's face.

6. CN II – OPTIC:
OPHTHALMOSCOPE
•Expensive piece of equipment
•Use appropriately

7. ALL TOGETHER NOW …
Cranial Nerves III, IV, and VI
 III Oculomotor
 IV Trochlear
 VI Abducens
Observation
 Examine the upper and lower lids by observation.
Look to see that the opening between the
eyelids, or the "palpebral fissures", are equal on
both sides, and that each lid relates
symmetrically to the cornea. Make sure to
observe both upper and lower lids.
 Next, observe the pupils in normal room light to
see if they are symmetric.

8. CRANIAL NERVES III, IV, AND VI (MOTOR)
Four tests
1. Direct Light Reflex
2. Consensual Light Reflex
3. Accommodation
4. Six Cardinal Fields of Gaze

9. CRANIAL NERVES III, IV, AND VI
Direct Light Reflex
 Each pupil should
constrict briskly when
the light strikes the
pupil.
 Move the light in from
the temporal side.
 Document the reaction
in mm (e.g., 6mm 
4mm).

10. CRANIAL NERVES III, IV, AND VI
Consensual Light
Reflex
 Perform the procedure
again, exactly as
before for Direct Light
Reflex… only this time
watch the opposite
pupil.
 It should react the
same as the pupil in
which the light is
shined.

11. CRANIAL NERVES III, IV, AND VI
Accommodation - adaptation of the
eyes for near vision
 Ask the patient to focus on a distant light
(e.g., a wall or door) at their eye level and
maintain that gaze until directed
otherwise.
 Hold an object (pencil, penlight, finger)
about 18" from the patient's nose.
 Ask him to change his focus from the
distant object to the closer one.
 As he does so, observe his eyes as they
converge (turn inward) and the pupils
constrict.

12. CRANIAL NERVES III, IV, AND
VI
Document normal reactions as PERLA!
 Pupils
 Equally
 Reactive to
 Light and
 Accommodation

13. CRANIAL NERVES III, IV, AND
VI
Document abnormal eye movements
 Some key terms to know
1. Nystagmus: constant, involuntary, cyclical movement
2. Saccadic: jerky, rapid, intermittent movements
3. Tracking: lagging, catching up movement
4. Vergence: turning of one eye without reference to the other, which may indicate
weakness of oblique muscles.

14. CRANIAL NERVES III, IV, AND VI
Six Cardinal (primary) Fields of Gaze:
tests for extraocular movement
 Six fields correspond roughly to 12,
2, 4, 6, 8, 10 on a clock face
 Hold an object (pen, penlight,
finger) about 12" from the patient's
nose.
 Instruct the patient to keep his head
still and to follow the object's
movement to the six cardinal fields
with his eyes only.
 Slowly move the object through
each vision field separately,
observing both eyes simultaneously.

15. CN V – TRIGEMINAL (SENSORY AND MOTOR)
As the name
suggests, the
trigeminal nerve
innervates 3
sections of the
face:
1.ophthalmic
2.maxillary
3.mandibular

16. CN V – TRIGEMINAL
Sensory Assessment
 Begin by assessing ability to sense light touch
to the face.
 Ask the patient to close his/her eyes and to tell
you what he/she feels, and when and where
he/she feels it.
 Using a fine wisp of cotton or your fingertip,
gently test the forehead, cheeks, and jaw,
randomly and bilaterally.
 The patient should be able to identify the same
sensation bilaterally, and tell when and where
he/she feels the touch.
 If not, repeat the test using the sharp and blunt
ends of a sterile pin to check sensitivity to pain.
 Sensitivity to temperature may also be tested
using test tubes with warm and cool water.

17. CN V – TRIGEMINAL
Corneal Reflex Test
 Usually not done if light touch
is intact
 Instruct the patient to look up
and away from you.
 Approaching the patient
laterally, out of his line of
vision, and avoiding the
eyelashes, touch the cornea
lightly with a fine wisp of
cotton.
 Look for blinking of the eyes,
the normal reaction to this
stimulus.
 Be aware that use of contact
lenses frequently diminishes,
or may even eliminate, the
corneal reflex response.
The corneal reflex tests
the afferent (sensory) arc
of CN V, and the efferent
(motor) arc of CN VII.

18. CN V – TRIGEMINAL
Motor Assessment
 Ask the patient to clench his/her teeth.
 While he/she is clinching, palpate the
temporal muscles.
 You should note symmetrical strength.
Move your hands to the area of the
masseter muscles and ask the patient to
clench again.
 Bilateral contraction should be equally
strong.
 To assess chewing ability, ask the patient
to clench and unclench his/her jaws
several times while you observe for
distorted movements or asymmetry.

19. CN VII – FACIAL (SENSORY AND MOTOR)
Motor assessment
 Observation during conversation
 Facial symmetry during spontaneous expression
 Wrinkling the nose
 Smiling and frowning
 Closing eyes
 Grimacing
 Intentional expression; ask the patient to
 Raise and lower eyebrows
 Squeeze eyes shut tightly
 Smile showing teeth
 Puff out cheeks

20. CN VII – FACIAL
Sensory assessment
 Usually not done unless problems are noted during motor
assessment
 CNVII responsible for taste on anterior 2/3 of the tongue
 With patient’s eyes closed, check for recognition of common, easily
distinguishable tastes such as chocolate or lemon

21. CN VIII – ACOUSTIC (SENSORY AND
MOTOR)
aka Vestibulocochlear nerve
Two branches
 Vestibular nerve branch controls balance and equilibrium
 Cochlear nerve branch controls hearing
Vestibular branch not usually checked unless
several symptoms of abnormality exist
 Vertigo
 N/V
 Nystagmus
 Postural deviation
 Pallor
 Sweating
 Hypotension

22. CN VIII – ACOUSTIC
Sensory assessment
 To make a gross assessment of
the cochlear division, begin by
instructing the patient to close his
eyes and tell you what he hears
and in which ear.
 Gently rub your fingers together
about 6" away from first one ear,
then the other, then both
simultaneously.
 If deficit is suggested, a more
precise assessment may be done
with a tuning fork.

23. CN IX & X – SENSORY AND
MOTOR
CN IX Glossopharyngeal
CN X Vagus
Cranial nerves nine and ten are tested
together, because they are closely associated
and similar in function.
The motor aspect of the glossopharyngeal
nerve innervates the muscle used to swallow.
Its sensory component supplies sensation to
the pharynx and is responsible for taste
perception on the posterior 1/3 of the
tongue, and for salivation.

24. CN X – VAGUS!
The vagus nerve controls:
 swallowing
 phonation (the process of uttering vocal sounds)
 movement of the uvula and soft palate.
CN X also innervates the thoracic and abdominal visceral
organs!
 Carries sensory impulses from the GI tract, the heart, and the lungs

25. CN IX & X – ASSESSMENT
Begin assessment of these
2 nerves by inspecting the
soft palate.
When the patient says "ah",
the palate should rise
promptly and
symmetrically.
The uvula should NOT be
used to assess symmetry,
because there are many
normally odd-shaped
structures.

26. CN IX & X – ASSESSMENT
The gag reflex assesses the sensory component of
CN IX, and the motor response of CN X.
Touch the posterior pharynx lightly with a cotton-
tipped applicator.
Test the palatal reflex, stroke the posterior
portion of the palate on each side with the
applicator.
In both instances, the palate should elevate and a
gag response should be induced.
However, remember that normal patients
frequently manifest bilateral loss of the gag
reflex, especially patients with a history of
smoking or tobacco use.

27. CN XI – SPINAL ACCESSORY
(MOTOR)
The spinal
accessory nerve
supplies the
sternocleidomastoid
muscles and the
upper portion of the
trapezius muscles.

28. CN XI – SPINAL ACCESSORY
To assess sternocleidomastoid strength, apply
resistance to the jaw and have the patient try to
turn his head to the side against your pressure.
To evaluate the trapezius, watch the patient shrug
his shoulders, which should move at the same
speed and with roughly the same extent of
movement.
Next, ask the patient to shrug his shoulders
upward while you try to hold them down.

29. CN XII – HYPOGLOSSAL
(MOTOR)
Responsible for
normal tongue
movements.
First observe the
tongue at rest on the
floor of the mouth.
Look for:
 asymmetry
 deviation to one side
 loss of bulk on one side
 fasciculations
(involuntary contractions,
twitching)
Next, ask the patient
to stick out his
tongue.
It should protrude
along the midline [the
"median raphe"
(midline crease) lines
up with the notch
between the "medial
incisors" (two front
teeth)].

30. CN XII – HYPOGLOSSAL
Finally, have the patient
push his/her tongue as
hard as he/she can against
the inside of the cheek,
while you push using your
thumb against the outside
of the cheek.
Compare right and left
sides.
Remember that weakness
pushing the tongue into
the right cheek indicates
an abnormality in the left
hypoglossal nerve, and vice
versa.