The 12 Cranial Nerves: Names, Functions, Chart & Bedside Assessment

Cranial nerves can feel like a lot of memorization. Twelve pairs, three letter-pair classifications, and a dozen mnemonic words that all start with “O” or “T.” The good news: once you see the structure — names in order, sensory vs motor vs both, and the bedside test for each one — the whole topic fits into a single one-page reference. Let’s build that page.

This guide is the comprehensive 12-cranial-nerves reference for nursing students: every nerve with its function, point of exit from the skull, and how it’s tested at the bedside, plus the high-yield clinical correlations you’ll see on the NCLEX. For the deep-dive on the mnemonics, head to our dedicated cranial nerves mnemonic guide.

What are the 12 cranial nerves? The 12 cranial nerves are paired nerves (one on each side) that emerge directly from the brain and brainstem — numbered I through XII in the order they appear from front to back. Each is sensory, motor, or both. They control smell, vision, eye movements, facial sensation and expression, hearing, balance, taste, swallowing, voice, neck movement, and tongue movement. The classic mnemonic for the order is On Old Olympus’s Towering Tops, A Finn And German Viewed Some Hops.[1][2]

The 12 cranial nerves at a glance

The master reference. Every nurse should be able to read this table cold by the end of nursing school.

Sources: [1] Cleveland Clinic · [2] NCBI/StatPearls · [3] Moore’s Clinically Oriented Anatomy · [4] Bates’ Guide to Physical Examination.

Sensory, motor, or both — the type pattern

Each cranial nerve is one of three types: pure sensory, pure motor, or both (carries both fiber types).

• Sensory only (3): I, II, VIII — Olfactory, Optic, Vestibulocochlear
• Motor only (5): III, IV, VI, XI, XII — Oculomotor, Trochlear, Abducens, Accessory, Hypoglossal
• Both (4): V, VII, IX, X — Trigeminal, Facial, Glossopharyngeal, Vagus

The pattern from CN I → XII reads S-S-M-M-B-M-B-S-B-B-M-M.

The classic memory aid for this pattern is “Some Say Marry Money But My Brother Says Big Brains Matter Most.”

Each of the 12 cranial nerves

A short deep dive on every nerve — function, exit, bedside test, and the high-yield clinical note. (Patient names and clinical specifics here are illustrative, not specific cases.)

CN I — Olfactory (sensory)

The olfactory nerve carries smell from the nasal mucosa, through the cribriform plate of the ethmoid bone, to the olfactory bulb in the brain.[1][2]

Bedside test: ask the client to close their eyes, occlude one nostril, and identify a familiar non-irritating scent (coffee, vanilla, mint). Repeat on the other side.

High-yield: olfactory testing is rarely positive in routine practice; bedside assessment is often deferred unless head trauma, frontal-lobe pathology, or new-onset anosmia is suspected. Loss can follow basilar skull fracture across the cribriform plate.[4]

CN II — Optic (sensory)

The optic nerve carries visual information from the retina through the optic canal to the optic chiasm and on to the visual cortex.[1][2]

Bedside test: visual acuity (Snellen chart, near card), visual fields by confrontation, pupillary light reflex (CN II is the afferent limb), funduscopic exam of the optic disc.

High-yield: the pupillary light reflex tests both CN II and CN III together — afferent (CN II) and efferent (CN III). Light in one eye normally produces direct constriction (same eye) and consensual constriction (other eye).[4]

CN III — Oculomotor (motor)

The oculomotor nerve does most eye movements (medial, superior, and inferior rectus; inferior oblique), elevates the eyelid (levator palpebrae), and carries parasympathetic fibers that constrict the pupil.[1][2]

Bedside test: pupillary reaction to light (efferent), extraocular movements in the H-pattern, observe for ptosis (lid droop).

High-yield: a CN III palsy classically presents with ptosis, “down and out” eye position, and a fixed, dilated pupil — the dilated pupil is a red flag for compressive lesions (uncal herniation, posterior communicating artery aneurysm).[2][4] Document and escalate immediately.

CN IV — Trochlear (motor)

The trochlear nerve innervates one muscle: the superior oblique, which moves the eye “down and in.”[1][2]

Bedside test: ask the client to look down and toward the nose; complain of diplopia when reading or descending stairs in CN IV palsy.

High-yield: the trochlear is the only cranial nerve that exits the dorsal (posterior) brainstem and crosses to the opposite side before innervating its target — making it especially vulnerable to head trauma.[3]

CN V — Trigeminal (both)

The trigeminal has three sensory divisions — V1 ophthalmic, V2 maxillary, V3 mandibular — covering the entire face. Its motor branch (in V3) supplies the muscles of mastication.[1][2]

Bedside test: light touch and pinprick on the forehead (V1), cheek (V2), and jaw (V3); ask the client to clench teeth and feel the masseter and temporalis contract.

High-yield: trigeminal neuralgia presents as paroxysmal, lancinating (“electric shock”) pain in one or more V divisions, often triggered by light touch, brushing teeth, or wind. The corneal reflex tests V1 (afferent) and CN VII (efferent — blink).[2][4]

CN VI — Abducens (motor)

The abducens nerve innervates one muscle: the lateral rectus, which abducts the eye (moves it laterally).[1][2]

Bedside test: ask the client to look to the side; failure to abduct results in medial gaze deviation on the affected side.

High-yield: CN VI has the longest intracranial course of any cranial nerve, which makes it sensitive to increased intracranial pressure. New CN VI palsy in a patient with headache or papilledema is a red flag for raised ICP.[2]

CN VII — Facial (both)

The facial nerve controls the muscles of facial expression, carries taste from the anterior two-thirds of the tongue, and supplies parasympathetic fibers to the lacrimal and salivary glands.[1][2]

Bedside test: ask the client to smile symmetrically, raise their eyebrows, puff their cheeks, close their eyes tightly, show their teeth.

High-yield (huge for the NCLEX): central vs peripheral CN VII palsy. A central lesion (e.g., stroke) spares the forehead because the upper face receives bilateral cortical input. A peripheral lesion — classic Bell’s palsy — affects the entire side of the face, including the forehead. This distinction is the difference between “stroke until proven otherwise” and “Bell’s palsy with corneal-protection precautions.”[2][4]

CN VIII — Vestibulocochlear (Acoustic) — sensory

The vestibulocochlear nerve has two divisions: cochlear (hearing) and vestibular (balance/equilibrium). Both exit through the internal acoustic meatus.[1][2]

Bedside test: whisper test or finger-rub for hearing; Weber (tuning fork on midline forehead — lateralization indicates conductive vs sensorineural loss) and Rinne (mastoid vs ear-canal comparison) for hearing pattern; Romberg for vestibular/proprioceptive integration.

High-yield: ototoxic medications (aminoglycosides, loop diuretics, cisplatin) damage CN VIII — monitor for new tinnitus, hearing loss, or vertigo in patients on these agents.[4]

CN IX — Glossopharyngeal (both)

The glossopharyngeal nerve carries taste from the posterior third of the tongue, sensation from the pharynx and middle ear, motor to one swallowing muscle (stylopharyngeus), parasympathetic to the parotid gland, and sensation from the carotid body.[1][2]

Bedside test: gag reflex — afferent limb is CN IX; touch the posterior pharyngeal wall with a tongue blade. (Don’t confuse with the efferent limb, which is CN X.) Ask the client to say “ahhh.”

High-yield: CN IX and CN X are typically tested together because they share the gag reflex pathway. An absent or asymmetric gag reflex points to one of the two — confirm with palatal elevation (CN X).[4]

CN X — Vagus (both)

The vagus is the longest and most widely distributed cranial nerve. It carries parasympathetic fibers to thoracic and abdominal viscera (heart, lungs, GI tract), motor to the soft palate / pharynx / larynx, and sensation from those structures.[1][2]

Bedside test: gag reflex (efferent limb), voice quality (hoarseness suggests recurrent laryngeal involvement), uvula elevation when saying “ahhh” — should rise in the midline.

High-yield: with a unilateral CN X lesion, the uvula deviates away from the affected side (the intact side pulls it over). The opposite pattern applies to CN XII at the tongue (see below).[2][4]

CN XI — Spinal Accessory (motor)

The spinal accessory innervates two large muscles of the neck and shoulder: the sternocleidomastoid (SCM) and the trapezius. Most of its motor neurons originate in the upper spinal cord, then ascend through the foramen magnum to exit via the jugular foramen — hence “spinal accessory.”[1][2]

Bedside test: ask the client to shrug their shoulders against your resistance (trapezius) and turn their head against resistance (SCM — the SCM that contracts turns the head to the opposite side).

High-yield: weakness in shoulder shrug or head turn against resistance points to CN XI. Surgical injury during neck procedures (lymph node biopsy, carotid surgery) is a classic cause.[2]

CN XII — Hypoglossal (motor)

The hypoglossal nerve controls tongue movement — protrusion, retraction, and side-to-side motion.[1][2]

Bedside test: ask the client to stick out their tongue. Observe for deviation, atrophy, or fasciculations.

High-yield: with a unilateral CN XII lesion, the tongue deviates toward the affected side. (The unopposed contralateral genioglossus pushes it over.) Memorize this direction — and notice it’s the opposite of the uvula in CN X.[2][4]

Cranial nerves you might confuse — “don’t mix these up”

These are the high-yield mix-ups on the NCLEX and in clinicals.

The three “eye-movement” nerves (CN III, IV, VI) All three move the eye, but each one does a different thing.

• CN III does most movements (medial, up, down) plus lid elevation and pupil constriction.
• CN IV does one thing: “down and in” via the superior oblique.
• CN VI does one thing: lateral movement via the lateral rectus.

A “blown pupil” (fixed and dilated) points to CN III specifically — and it’s a red flag for compressive pathology.[2][4]

CN V vs CN VII — sensation vs expression The face has two big nerves and they split the work cleanly.

• CN V (Trigeminal) = facial sensation (V1, V2, V3) and the muscles of chewing (mastication).
• CN VII (Facial) = facial expression (smile, eyebrows, eye closure) and taste on the anterior 2/3 of the tongue.

If a client can feel their face but can’t move it on one side, that’s CN VII. If they can move their face but can’t feel it on one side, that’s CN V.[1][2]

CN VII central vs peripheral palsy — the highest-yield neuro distinction

• Central lesion (stroke, brain tumor) — forehead spared (upper face has bilateral cortical input).
• Peripheral lesion (Bell’s palsy, herpes zoster oticus) — forehead affected (the whole side of the face droops).

If a client can wrinkle their forehead on the affected side, think central → stroke workup. If they can’t, think peripheral → Bell’s palsy and corneal protection.[2][4]

CN IX vs CN X in the gag reflex

• CN IX = afferent limb (the sensation of the tongue-blade touch on the pharynx)
• CN X = efferent limb (the motor response — the gag itself)
• An absent gag could be either; confirm by checking palatal elevation (CN X) and voice quality (CN X — hoarseness).

CN X uvula deviation vs CN XII tongue deviation — opposite directions

• CN X lesion (uvula): uvula deviates away from the lesion side
• CN XII lesion (tongue): tongue deviates toward the lesion side

The two go in opposite directions and they’re constantly tested together. The trick: imagine the intact side doing the work. For the uvula, the intact side pulls it over (away). For the tongue, the intact contralateral genioglossus pushes it forward (toward).[2][4]

Quick memory aid for the 12 cranial nerves

Two mnemonics to start with:

• Classic order mnemonic: On Old Olympus’s Towering Tops, A Finn And German Viewed Some Hops.
• Sensory/motor/both mnemonic: Some Say Marry Money But My Brother Says Big Brains Matter Most.

For a full breakdown of cranial nerve mnemonics and memory tricks — including the SimpleNursing house version, function-specific memory hooks, and a printable mnemonic cheat sheet — see our guide on how to remember the 12 cranial nerves.

Free cranial nerves chart

A one-page reference for your clinical bag and study pack.

S = Sensory, M = Motor, B = Both. Pattern: S-S-M-M-B-M-B-S-B-B-M-M (“Some Say Marry Money But My Brother Says Big Brains Matter Most”).

Cranial nerves & clinical correlations (NCLEX-relevant)

A few clinical patterns that show up again and again. Lock these in.

The pupillary light reflex pathway. Light in the eye → CN II (afferent) → midbrain → CN III (efferent, parasympathetic) → pupillary constrictor. A normal reflex tests both nerves; an asymmetric or absent response tells you which limb is broken. New unilateral fixed/dilated pupil with depressed consciousness suggests uncal herniation compressing CN III — a neurosurgical emergency.[2][4]

Bell’s palsy vs stroke (CN VII central vs peripheral). The single most testable neuro distinction on the NCLEX. If the forehead is spared → think central (stroke workup). If the forehead is affected → think peripheral (Bell’s palsy → corneal protection, eye lubrication, follow-up for facial nerve recovery).[2][4]

Increased ICP and posturing. CN VI has the longest intracranial course and is sensitive to raised ICP; new diplopia in a patient with headache or altered mental status is a red flag. Worsening neuro exam — including changes in pupillary response (CN III) or progression to abnormal posturing — points to rostrocaudal brain deterioration. For the posturing patterns, see our guide to decorticate vs decerebrate posturing.[2]

Stroke and CN deficits. Different stroke locations cause different CN patterns — for example, lateral medullary (Wallenberg) syndrome affects CN IX, X, and XI; pontine strokes can affect CN V, VI, and VII. Documenting each CN finding helps the team localize the lesion. For a related care plan, see our stroke nursing care plan.[2][4]

Diabetic mononeuropathy. Diabetes commonly causes isolated CN III, IV, or VI palsies — typically pupil-sparing CN III palsy (because diabetes affects the central fibers but spares the peripheral parasympathetic ones).[4]

NCLEX practice questions

Five practice questions with worked rationales. Treat them like the real thing.

Question 1

A nurse asks a client to stick out their tongue, and the tongue deviates to the right. Which cranial nerve is most likely affected?

• A. Right CN V (Trigeminal)
• B. Right CN VII (Facial)
• C. Right CN XII (Hypoglossal)
• D. Left CN XII (Hypoglossal)

Question 2

A client presents with right-sided facial droop, including inability to wrinkle the right forehead. This finding is most consistent with:

• A. Central CN VII palsy (stroke)
• B. Peripheral CN VII palsy (Bell’s palsy)
• C. CN V (Trigeminal) neuralgia
• D. CN III (Oculomotor) palsy

Question 3

When the nurse shines a light in a client’s right eye, both pupils constrict normally. The consensual response tests which cranial nerves?

• A. CN II only
• B. CN III only
• C. CN II (afferent) and CN III (efferent)
• D. CN III (afferent) and CN II (efferent)

Question 4

Which set of cranial nerves is sensory only?

• A. I, II, VIII
• B. III, IV, VI
• C. V, VII, IX, X
• D. XI, XII

Question 5

A client cannot shrug their shoulders against resistance. Which cranial nerve is most likely affected?

• A. CN VII (Facial)
• B. CN IX (Glossopharyngeal)
• C. CN X (Vagus)
• D. CN XI (Spinal Accessory)

Frequently asked questions

What are the 12 cranial nerves and their functions?

The 12 cranial nerves are: I Olfactory (smell), II Optic (vision), III Oculomotor (most eye movements, pupil, lid), IV Trochlear (down-and-in eye movement), V Trigeminal (facial sensation, chewing), VI Abducens (lateral eye movement), VII Facial (facial expression, taste anterior 2/3), VIII Vestibulocochlear (hearing & balance), IX Glossopharyngeal (taste posterior 1/3, swallowing), X Vagus (parasympathetic to viscera, voice), XI Spinal Accessory (shoulder shrug, head turn), XII Hypoglossal (tongue movement).[1][2]

How are the cranial nerves numbered?

The cranial nerves are numbered with Roman numerals I through XII in the order they emerge from the brain — from anterior to posterior (front of the brain toward the brainstem). CN I emerges most rostrally; CN XII most caudally.[1][2]

Which cranial nerves are sensory only?

Three cranial nerves are sensory only: CN I (Olfactory), CN II (Optic), and CN VIII (Vestibulocochlear). Smell, vision, and hearing/balance. The S/M/B pattern is captured by the mnemonic Some Say Marry Money But My Brother Says Big Brains Matter Most.[1][2]

Which cranial nerves are motor only?

Five cranial nerves are motor only: CN III, IV, VI, XI, and XII. That’s the three “extra” eye-movement nerves (III, IV, VI) plus CN XI (shoulder/neck) and CN XII (tongue).[1][2]

Which cranial nerves are both sensory and motor?

Four cranial nerves carry both fiber types: CN V (Trigeminal), CN VII (Facial), CN IX (Glossopharyngeal), and CN X (Vagus). They all involve the face, mouth, or throat — places where sensation and movement are tightly linked.[1][2]

What’s the difference between central and peripheral CN VII palsy?

A central CN VII palsy (stroke, brain tumor) spares the forehead because the upper face receives bilateral cortical input. A peripheral CN VII palsy (Bell’s palsy, herpes zoster oticus) affects the entire side of the face, including the forehead. If the client can wrinkle the forehead on the affected side, think central. If not, think peripheral.[2][4]

Why does the tongue deviate toward the lesion side in CN XII palsy?

The hypoglossal nerve drives the genioglossus muscle, which protrudes the tongue and pushes it slightly contralaterally. With a unilateral CN XII lesion, the intact contralateral genioglossus is unopposed and pushes the tongue toward the affected side. Opposite direction from CN X at the uvula (which deviates away from the lesion).[2][4]

How are the cranial nerves tested at the bedside?

Each nerve has a specific bedside test — smell identification (I), visual acuity and pupillary reflex (II + III), eye movements (III, IV, VI), facial sensation and clench (V), facial expression (VII), hearing and balance (VIII), gag reflex and “ahhh” (IX, X), shoulder shrug (XI), and tongue protrusion (XII). The table at the top of this guide lists every test. For a full neuro exam, see our head-to-toe assessment guide.[4]

Take your neuro studying to the next level

Once the table is in your head and the bedside tests are second nature, the cranial nerves stop feeling like memorization and start feeling like a checklist. The 12 nerves cover smell to tongue movement — there’s a pattern, a mnemonic, and a clinical clue for each one.

For the full memory deep-dive — every mnemonic, every memory hook — see our guide on how to remember the 12 cranial nerves. For practical NCLEX prep, try SimpleNursing free for video lessons and the full bank of neuro practice questions. For related neuro topics, see our decorticate vs decerebrate guide, stroke nursing care plan, and head-to-toe assessment guide.

References

1. Cleveland Clinic. Cranial Nerves: Function, Anatomy & Location. my.clevelandclinic.org/health/body/21998-cranial-nerves
2. StatPearls Publishing / NCBI Bookshelf. Anatomy, Head and Neck, Cranial Nerves. ncbi.nlm.nih.gov/books/
3. Moore KL, Dalley AF, Agur AMR. Moore’s Clinically Oriented Anatomy. Current ed. Wolters Kluwer.
4. Bickley LS, Szilagyi PG. Bates’ Guide to Physical Examination and History Taking. Current ed. Wolters Kluwer.