Neuro4Nurses
Cranial Nerves Assessment
There are twelve pairs of cranial nerves. When
conducting a cranial nerves assessment, the patient
must be awake, cooperative, and cognitively intact.
Cranial Nerve I: Olfactory (Sensory)
CN I is not routinely tested. However, if the patient
has a base of skull fracture or complained of altered or
loss of sense of smell, CN I assessment should be
performed2.
Testing: Patient’s nostril must be patent. Ask patient to
close his/her eyes and close one nostril. Breathe
through the nose and identify the odor such as coffee
or lemon. Do not use strong odor such as ammonia or
alcohol. Strong odor may stimulate the pain sensation
of the trigeminal nerve and interfere with the
assessment results1,3. Test the other nostril in the
same manner.
Dysfunction of CN I
Changes or loss of the sensation of smell is the
malfunction of the frontal lobe3. It can be caused by
trauma, congenital causes, infection (sinusitis, rhinitis),
cigarette smoking, normal aging, and epilepsy3.
Cranial Nerve II: Optic (Sensory)
The optic nerve (CN II) controls the visual acuity
and visual field2. It is also involves in the pupil
response to light.
Testing: Visual acuity: Patient wears the appropriate
glasses if required. Cover one eye and ask patient to
read from the chart. Use the Snellen chart if patient is
mobile and the Rosenbaum Pocket Vision Screener if
patient is bed ridden. If patient is illiterate or unable to
read English, ask patient to identify objects in pictures2.
Repeat the process for the other eye.
Testing: Visual field: Visual field is the area that a
person can see with one eye4. Instruct patient to cover
one eye and look at the examiner’s eye. Move fingers
from peripheral to central. Patient is asked to say “now”
once he/she starts to see your finger. Patient’s visual
field should be similar to the examiner’s visual field.
Dysfunction of CN II
Dysfunctions of optic nerve include blindness, visual
field deficits, blurring of vision, scotoma, and diplopia5.
Cranial Nerve III: Oculomotor (Motor) Cranial Nerve
IV: Trochlear (Motor); Cranial Nerve VI: Abducens
(Motor)
Cranial nerves III, IV, VI control the extraocular eye
movement. CN III also controls the eye opening and
dilation and constriction of the pupils1,2.
Testing of cranial nerves III, IV, and VI
Usually cranial nerve III, IV, and V are tested in one
simple assessment. Patient is asked to look at and
follow the examiner’s finger while examiner is drawing
a large H in the air. This can assess the patient’s
extraocular movement in all six directions2.
CN III
CN III
CN III
CN
VI
CN
VI
VI
V
VI
VI
V
VI
CN III
CN III
CN IV
CN III
VIVV
Diagram showing the movement of the eyes in relation to the
I cranial nerves
control of the
Dysfunction of the cranial nerve III, IV, and VI
Patients with a frontal lobe stroke may have eye
deviate to the affected side. Patients with a cerebral
hemorrhage may have eye deviation away from the
affected side7.Diplopia or double vision is usually
related to dysfunction or asynchronous of the
extraocular muscle movement. Ptosis is the drooping
of eyelid. It is resulted from the dysfunction of CN III or
neuromuscular diseases such as myasthenia gravis or
Horner’s syndrome7.
Cranial Nerve V: Trigeminal (Sensory & Motor))
The trigeminal nerve has three branches. It is
involved in the pain and temperature sensation of the
face, corneal reflex, and mastication8.
Testing: Motor: Ask patient to clench the teeth. The
jaw should be tightly close.
Testing Sensory: Ask patient to close his/her eyes
and test pain sensation on both sides of the face.
Corneal reflex: Patient should blink briskly and
bilaterally when the eye is slightly touched with a piece
of cotton.
Dysfunction of CN V
Trigeminal neuralgia may be may be idiopathic or
due to demyelination of the nerve root. The patient
experiences severe pain when stimulated especially in
the maxillary and mandibular branch areas8.
Cranial Nerve VII: Facial (Motor)
The facial nerve controls facial movement.
Testing: Observe the patient’s face for any asymmetry
at rest and when the patient is smiling, raising both eye
brows, showing teeth, or puffing out both cheeks.
Dysfunction of CN VII
CN VII dysfunction may cause facial asymmetry.
The commonly dysfunction of CN VII is Bell’s Palsy. It’s
causes include idiopathic, infection, tumor, or trauma.
Patients with Bell’s palsy may experience pain,
transient loss of sensation and paralysis on one side of
the face8.
Cranial Nerve VIII: Acoustic (Sensory)
Cranial
nerve
VIII
is
also
known
as
vestibulocochlear nerve. It’s functions include hearing
and balancing.
Testing: Hearing: Ask the patient to cover one ear
and whisper to the unoccluded ear. Use words or
numbers with two equally accented syllables such as
baseball or five-four4. Perform the same test on the
other ear.
Balancing: Vestibular function is not commonly tested
unless the patient complains about dizziness or
vertigo.
Dysfunction of CN VIII
Deafness, decreased hearing acuity, or tinnitus
(perception of a continuous high-pitched ringing sound
without any actual auditory input) may be a resulted of
congenital causes, obstruction, aging, infection,
trauma, or extreme noise exposure9.
Dizziness is a sensation of imbalance and vertigo is
a false sensation of turning9.
Cranial Nerve IX (CN IX): Glossopharyngeal
(Sensory & Motor)
The glossopharyngeal nerve supplies the tongue
and pharynx and is part of the parasympathetic
system. It involves in the swallowing gagging, and
vomiting process, and sensation of the posterior third
of the tongue 10.
Testing: To avoid vomiting, gag reflex is not assessed
normally. Assess the sweet taste and observe the
upward and forward movement of the larynx when
swallowing9.
Dysfunction of CN IX
Patient who has CN IX dysfunction may be able to
swallow without aspiration11.
Cranial Nerve X: Vagus Nerve (Sensory & Motor)
The vagus nerve has sensory, motor, and
parasympathetic functions. It receives sensation from
the larynx, pharynx, and abdominal organs10. The
motor division of the vagus nerve controls the posterior
portion of the tongue during swallowing, speech, and
breathing10.
Testing: Common test for CN X includes listening for
any hoarseness of the voice during conversation. Ask
the patient to open his/her mouth and say “ah” and
observe for uvula deviation. Uvula will deviate away
from the side of lesion. Assess for swallowing reflex
4,11
.
Dysfunction of CN X
Dysphagia is defined as difficulty in swallowing. A
proper swallowing assessment must be performed by a
trained professional (e.g. speech language pathologist)
for patients suspected to have dysphagia because of
the risk of aspiration. Dysartharia is the dysfunction of
motor speech when the patient has poor articulation of
words.
Cranial Nerve XI: Accessory or Spinal Accessory
(Motor)
The accessory nerve is also called spinal accessory
nerve. It controls the neck and shoulder movement.
Testing: Place both hands on the patient’s shoulder
and ask him/her to shrug both shoulders. Assess for
the muscle strength and symmetrical movement.
Place one hand on the patient’s cheek and ask the
patient to turn his/her head against your hand. Test for
motor strength. Then repeat on the other side of cheek.
Cranial Nerve XII (CN XII): Hypoglossal (Motor)
The hypoglossal nerve controls the intrinsic muscle
of the tongue12.
Testing: Ask the patient to open his/her mouth and
protrude his/her tongue. Observe for any atrophy,
difficulty in protrusion, and deviation of the tongue. The
tongue deviates to the weakness side. Also observe for
any dysarthria when the patient talks12.
Reference
1) Hickey, J.V. (2009). The Clinical Practice of Neurological and
th
Neurosurgical Nursing. (6 ed.). Philadelphia: J.B.Lippincott
Company.
2) Barker, E, & Moore, K. (1992). Cranial nerve assessment. RN, 55(5),
62-69.
3) Sanders, R.D., & Gillig, P.M. (2009a). Cranial nerve I: Olfactory.
Psychiatry, 6(7), 30-35.
4) Palmieri, R.L. (2009). Wrapping your head around cranial nerves.
Nursing, 39(9), 24-30.
5) Gillig, P.M., & Sanders, R.D. (2009). Cranial nerve II: Vision. Psychiatry,
6(9), 32-37.
6) Brazis, P.W. (2009). Isolated palsies of cranial nerves III, IV, and VI.
Seminars in Neurology, 20(1), 14-28.
7) Sanders, R.D., & Gillig, P.M. (2009b). Cranial nerve III, IV, and VI:
Ocular function. Psychiatry, 6(11), 34-39.
8) Gillig, P.M., & Sanders, R.D. (2010a). The trigeminal (V) and facial (VII)
cranial nerve: Head and face sensation and movement. Psychiatry,
7(1), 25-30.
9) Sanders, R.D., & Gillig, P.M. (2010). Cranial nerve . Psychia
10) Erman, A.B., Kejner, A.E., Hogikyan, N.D., & Feldman, E.L. (2009).
Disorders of cranial nerves IX and X. Seminars in Neurology, 29 (1), 8592.
11) Gillig, P.M., & Sanders, R.D. (2010b). Cranial nerves IX, X, XI, and XII.
Psychiatry, 7(5), 37-41.
12) Loh, C., Maya, M.M., & Go, J.L. (2002). Cranial nerve XII: The
hypoglossal nerve. Seminars in Ultrasound, CT, and MRI, 23(3), 256265.
©2013
Disclaimer: The author of this article neither represents nor guarantees that the
practices described herein, if followed, ensure safe and effective patient care. The
author further assumes no responsibility or liability in connection with any
information or recommendations contained in this article. The recommendations and
instructions in this article are based on the knowledge and practice in neuroscience
as of the date of publication. These recommendation and instructions are subject to
change based on the availability of new scientific information.