Cranial Nerve Assessment: Complete Nursing Neuro Exam Guide
A cranial nerve assessment is a focused neurologic exam that helps nurses recognize deficits in vision, eye movement, facial strength, sensation, hearing, swallowing, speech, shoulder movement, and tongue movement.
Cranial nerves can feel like pure memorization in school, but at the bedside they are practical. A new facial droop, diplopia, visual field cut, dysarthria, abnormal pupil, or tongue deviation can help localize a neurologic problem and escalate care quickly.
- What Cranial Nerves Are
- Fast Cranial Nerve Screen
- CN I: Olfactory
- CN II: Optic
- CN III: Oculomotor
- CN IV: Trochlear
- CN V: Trigeminal
- CN VI: Abducens
- CN VII: Facial
- CN VIII: Vestibulocochlear
- CN IX & X: Glossopharyngeal and Vagus
- CN XI: Accessory
- CN XII: Hypoglossal
- Cranial Nerve Assessment Cheat Sheet
- References
What Are the Cranial Nerves?
Cranial nerves are twelve paired nerves that arise from the brain or brainstem and carry sensory, motor, and autonomic information between the brain and structures of the head, neck, and parts of the thorax and abdomen.
They are numbered from I to XII from front to back. Some are mostly sensory, some are mostly motor, and some are mixed.
Fast Cranial Nerve Screen for Bedside Nursing
For many inpatient or emergency assessments, you will use a quick screen first. If anything is abnormal, repeat the exam more carefully and escalate according to facility policy.
Look for facial droop, ptosis, unequal pupils, abnormal gaze, dysarthria, dysphagia, hoarseness, tongue deviation, or obvious visual neglect.
Assess pupil size, shape, equality, light response, reported vision changes, and visual fields when indicated.
Have the patient follow your finger through the six cardinal directions. Watch for diplopia, gaze palsy, asymmetry, and sustained nystagmus.
Check smile, eyebrow raise, eye closure, forehead movement, and facial sensation in the forehead, cheek, and jaw regions.
Listen for dysarthria, aphasia-like concerns, hoarseness, wet voice, choking, or difficulty managing secretions.
Ask for shoulder shrug/head turn against resistance, then tongue protrusion and side-to-side movement.
New Focal Neuro Deficit = Escalate
New facial droop, unilateral weakness, visual field loss, aphasia, dysarthria, severe sudden headache, abnormal pupils, or acute gaze changes should trigger urgent stroke/neuro evaluation per protocol. Do not let a “mostly normal” cranial nerve exam delay escalation.
CN I: Olfactory Nerve
The olfactory nerve is responsible for smell. It is rarely tested in routine acute care, but smell changes can occur with sinonasal disease, viral illness, trauma, neurodegenerative conditions, and less commonly intracranial pathology.
How to Test CN I
Ask the patient to close their eyes. Occlude one nostril at a time and present a familiar, non-irritating scent such as coffee, vanilla, cinnamon, or peppermint. Ask the patient to identify the scent.
Avoid Irritants
Do not use ammonia or alcohol to test smell. Irritating substances can stimulate trigeminal nerve endings rather than purely testing olfaction.
CN II: Optic Nerve
The optic nerve carries visual input from the retina to the brain. In bedside practice, CN II is commonly assessed through visual acuity, visual fields, and the afferent limb of the pupillary light reflex.
CN III: Oculomotor Nerve
The oculomotor nerve controls most extraocular movements, eyelid elevation, and pupillary constriction. Dysfunction may cause ptosis, diplopia, impaired eye movement, and sometimes a dilated pupil.
Dilated Pupil + Ptosis + Eye Deviation
An acute third nerve palsy with pupillary involvement is concerning for compressive pathology such as aneurysm until proven otherwise. Escalate immediately.
Testing Extraocular Movements: CN III, IV, and VI
Hold a finger or pen about 18–24 inches from the patient’s face. Ask them to follow it with their eyes only. Move through the six cardinal directions, returning to midline between movements. Watch for smoothness, symmetry, diplopia, gaze palsy, ptosis, and nystagmus.
CN IV: Trochlear Nerve
The trochlear nerve innervates the superior oblique muscle. Trochlear palsy can cause vertical diplopia, difficulty looking down and inward, and a compensatory head tilt. Patients may notice symptoms most when reading or walking downstairs.
CN IV is usually tested as part of the extraocular movement exam described above.
CN V: Trigeminal Nerve
The trigeminal nerve carries facial sensation and controls the muscles of mastication. Its three major sensory branches are ophthalmic (V1), maxillary (V2), and mandibular (V3).
How to Test CN V
CN VI: Abducens Nerve
The abducens nerve innervates the lateral rectus muscle, which abducts the eye. CN VI palsy can cause horizontal diplopia and difficulty moving the eye outward.
Because the abducens nerve has a long intracranial course, it can be affected by increased intracranial pressure, trauma, microvascular disease, and other neurologic conditions. Test it during the EOM exam by checking lateral gaze.
CN VII: Facial Nerve
The facial nerve controls muscles of facial expression and contributes to taste on the anterior tongue, lacrimation, and salivation. At the bedside, nurses most often assess facial symmetry and movement.
How to Test CN VII
Look for facial droop, flattened nasolabial fold, asymmetry, eyelid weakness, or inability to close one eye fully.
Ask the patient to raise their eyebrows or wrinkle their forehead. Compare symmetry.
Ask the patient to close their eyes tightly. Check whether one eyelid can be opened more easily than the other when clinically appropriate.
Ask the patient to smile, show teeth, and puff out their cheeks. Watch for lower facial weakness or air leak.
Bell’s Palsy vs Stroke
Peripheral facial nerve palsy often affects the forehead and lower face on the same side. Central lesions often affect the lower face more than the forehead, but this is not perfect. Use the whole clinical picture and escalate acute facial weakness as a possible stroke until evaluated.
CN VIII: Vestibulocochlear Nerve
The vestibulocochlear nerve supports hearing and balance. Dysfunction can present with hearing loss, tinnitus, vertigo, dizziness, gait instability, nausea, or nystagmus.
How to Test CN VIII
For a quick hearing screen, rub fingers near each ear or whisper a word/number while occluding the opposite ear. Compare side to side. Assess balance and gait only if safe. New vertigo with focal neurologic deficits, severe gait ataxia, diplopia, dysarthria, weakness, or direction-changing nystagmus is concerning for central pathology.
CN IX and X: Glossopharyngeal and Vagus Nerves
The glossopharyngeal nerve contributes to taste and sensation in the posterior tongue/pharynx and the afferent limb of the gag reflex. The vagus nerve contributes to palatal elevation, voice, swallowing, cough, parasympathetic function, and the efferent limb of the gag reflex.
How to Test CN IX and X
CN XI: Accessory Nerve
The accessory nerve innervates the sternocleidomastoid and trapezius muscles. It supports head rotation and shoulder shrug.
How to Test CN XI
Ask the patient to shrug both shoulders while you apply downward resistance. Then place your hand against one cheek and ask the patient to turn their head against resistance; repeat on the other side. Compare strength and symmetry.
CN XII: Hypoglossal Nerve
The hypoglossal nerve controls most tongue movement. Dysfunction can contribute to dysarthria, dysphagia, tongue weakness, atrophy, fasciculations, or deviation.
How to Test CN XII
Ask the patient to stick out their tongue. A lower motor neuron hypoglossal lesion typically causes the tongue to deviate toward the weak side. Ask them to move the tongue side to side and listen for dysarthria during normal speech.
Cranial Nerve Assessment Cheat Sheet
Use this quick reference when you need to remember what each nerve does and the practical bedside test.
Smell. Test one nostril at a time with a familiar, non-irritating scent when indicated.
Vision. Check visual acuity, visual fields, and the afferent limb of the pupillary light reflex.
Eye movement, eyelid elevation, pupil constriction. Test EOMs, ptosis, and pupillary response.
Down-and-in eye movement. Test with EOMs and ask about vertical diplopia.
Facial sensation and chewing. Test V1/V2/V3 sensation and jaw strength.
Lateral eye movement. Test lateral gaze during EOMs.
Facial movement. Test smile, forehead raise, eye closure, cheek puff, and symmetry.
Hearing and balance. Screen hearing; assess gait/balance only when safe.
Posterior pharyngeal sensation, taste, swallow/gag afferent. Assess voice, swallow concerns, palate movement; gag only if indicated.
Palate, voice, swallow, cough, autonomic functions. Assess voice, palate elevation, swallowing, and cough quality.
Shoulder shrug and head turn. Test trapezius and sternocleidomastoid against resistance.
Tongue movement. Assess tongue protrusion, side-to-side movement, deviation, and dysarthria.
Clinical Pearls
Need the Cranial Nerve Cheat Sheet?
Use the downloadable handout as a quick practice reference when you are learning the neuro exam or refreshing cranial nerve testing.
- All 12 cranial nerves in one quick-reference format
- Bedside test reminders for nurses and students
- Simple charting-friendly assessment language
Related Clinical Guides
References
- Reese V, et al. Cranial Nerve Testing. StatPearls. National Library of Medicine. NCBI Bookshelf.
- Shahrokhi M, et al. Neurologic Exam. StatPearls. National Library of Medicine. NCBI Bookshelf.
- National Institute of Neurological Disorders and Stroke. NIH Stroke Scale. NINDS.
- Merck Manual Professional Edition. Facial Nerve Palsy. Merck Manual.
- Gelb D. The detailed neurologic examination in adults. UpToDate. UpToDate.
- Lee AG. Third cranial nerve palsy in adults. UpToDate. UpToDate.
- Lee AG. Fourth cranial nerve palsy. UpToDate. UpToDate.
- Rea P. Clinical Anatomy of the Cranial Nerves. Academic Press; 2014.
[…] (EOMs) are responsible for eye movement and are largely innervated by the third cranial nerve – the oculomotor cranial nerve, as well as the 4th and 6th cranial nerves. Intact EOMs suggests that those three cranial nerves […]
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