I Olfactory – Smell
II Optic – Vision
VII Facial – Expression & Taste
Mnemonic for all 12 nerves: “Oh Oh Oh To Touch And Feel Very Green Vegetables, AH!”

Peripheral Nerve Anatomy

Axons → wrapped in myelin → grouped into fascicles → surrounded by connective tissue.
Myelin helps speed up nerve signals (like insulation on wires).

Neurologic Problems

Key Points

Stroke = Brain Attack – Time = Brain!
Increased ICP (Intracranial Pressure) is a life-threatening emergency.
Seizures ≠ Epilepsy unless they are recurring without cause.
TIA is a warning sign – treat it seriously!

Stroke (Cerebrovascular Accident – CVA)

What Is a Stroke?

Sudden interruption of blood flow to the brain
- Ischemic (block) – 87%
- Hemorrhagic (bleed)

Types of Strokes

Ischemic: Blocked artery, caused by thrombus or embolus
Hemorrhagic: Bleeding in brain tissue, caused by ruptured aneurysm or trauma
TIA (Transient Ischemic Attack): Mini-stroke, resolves in <24 hr, warning of future stroke

Key Symptoms (FAST)

Face drooping
Arm weakness
Speech difficulty
Time to call 911

Treatment & Nursing Priorities

CT scan STAT to rule out bleeding.
Ischemic → tPA within 3–4.5 hours.
Hemorrhagic → control BP, surgery if needed.
Monitor for ICP
Prevent aspiration (NPO until swallow eval)

Intracranial Pressure (ICP)

Skull Components

Brain (80%) + CSF (10%) + Blood (10%)
Monro-Kellie Doctrine: If one increases, the others must decrease to prevent pressure.

Early Signs of ↑ ICP

Headache
Nausea/vomiting
Restlessness
Blurred vision

Late Signs (Neuro Emergency)

Cushing's Triad:
- ↑ Systolic BP (widened pulse pressure)
- ↓ HR (bradycardia)
- ↓ RR (irregular breathing)
Pupillary changes
Posturing (decorticate, decerebrate)
Coma

Nursing Care

Keep head midline
Elevate HOB 30°
No coughing, straining
Monitor neuro status frequently
Avoid hypotonic fluids! (can worsen cerebral edema)

Seizure Disorders

What Is a Seizure?

Sudden, uncontrolled electrical activity in the brain.

Types

Generalized: Entire brain; loss of consciousness
Tonic-clonic (grand mal): Stiffening + jerking
Absence (petit mal): Brief stare, mostly in kids
Focal: One hemisphere; may remain conscious
Status Epilepticus: Seizure >5 minutes or 2+ without recovery; medical emergency

Treatment

Benzodiazepines (Ativan) for active seizures
Anticonvulsants (phenytoin, levetiracetam) long-term
Seizure precautions: padded side rails, O2, suction ready

Nursing Tips

Turn patient on their side
Don’t restrain
Nothing in the mouth
Time the seizure
Document postictal (recovery) phase

Headaches

Migraine

Throbbing, unilateral, often with aura
Triggers: stress, chocolate, hormones
Treatment: triptans, NSAIDs, rest in dark room

Tension Headache

Band-like pressure, bilateral
Common with stress and poor posture

Cluster Headache

Intense stabbing pain, often around one eye
Occurs in “clusters” over weeks

Mnemonics

“CUSHING’S TRIAD”
- Chewing slower (↓ HR)
- Uncontrolled BP (↑ systolic)
- Slow RR
- It’s your brain’s last-ditch effort to survive pressure!

Ears and Sensory System

Key Points

The ear = hearing + balance
Hearing loss can be conductive or sensorineural.
Vertigo often comes from inner ear issues.
Safety is key with dizziness, tinnitus, or balance disorders.

Ear Anatomy & Function

3 Major Parts

Outer Ear: Auricle, auditory canal, collects sound
Middle Ear: Tympanic membrane, ossicles (malleus, incus, stapes) Transmits sound via vibration
Inner Ear: Cochlea, semicircular canals, hearing + balance

Key Structures

Cochlea = hearing (hair cells pick up sound waves)
Semicircular Canals = balance and spatial orientation
Eustachian Tube: connects middle ear to throat; equalizes pressure

Hearing Loss

Types of Hearing Loss

Conductive: Problem in outer/middle ear; sound can't reach cochlea (Earwax, fluid, otitis media)
Sensorineural: Damage to inner ear or nerve pathways (Noise exposure, aging, ototoxic meds)

Tests

Weber Test: tuning fork on forehead
- Conductive: sound louder in affected ear
- Sensorineural: sound louder in good ear
Rinne Test: compare bone vs. air conduction
- Normal: air > bone
- Conductive: bone > air

Balance & Dizziness

Vertigo vs. Dizziness

Vertigo = spinning sensation (Often inner ear cause like BPPV)
Dizziness = general unsteadiness

Meniere’s Disease

Inner ear disorder → excess fluid buildup
Triad: Vertigo, tinnitus, hearing loss
Risk for falls and injury!

Treatment

Diuretics, low-sodium diet, vestibular suppressants (meclizine)
Fall precautions!

Tinnitus

Ringing, buzzing, or roaring in the ears
Often from loud noise exposure or ototoxic meds
Can be permanent – protect your hearing!

Visual Connections

CN VIII (Vestibulocochlear): Hearing and balance
CN II (Optic): Vision
CN III, IV, VI: Eye movement
Damage can cause diplopia, nystagmus, or poor balance.

Memory Tips

Tinnitus Tip: “TINnitus sounds like a tin can buzzing in your ear!”
Weber/Rinne Quick Trick:
- Weber = “W” is for Where does the sound go?
- Rinne = “R” is for Right way (air > bone)

Nursing Priorities for Ear & Balance Disorders

Fall risk assessment
Turn head slowly
Dim lights if photophobia present
Hearing aids? Check batteries and fit
Speak clearly, don’t shout

Vision & Eye Disorders

Key Points

CN II (Optic Nerve) = Vision
CN III, IV, VI = Eye movement
Eye disorders can affect sight, safety, and independence.
Sudden vision loss = emergency!

Eye Anatomy Refresher

External Structures

Sclera: white part of the eye
Cornea: clear, dome-shaped front layer
Conjunctiva: thin membrane lining eyelids and eyeball

Internal Structures

Lens: Focuses light on the retina
Retina: Converts light to nerve impulses
Macula: Center of retina – sharp vision
Optic nerve (CN II): Carries vision signals to the brain
Aqueous humor: Fluid in front of lens (drainage issues = glaucoma)
Vitreous humor: Gel in eye that maintains shape

Cranial Nerves & the Eye

CN II (Optic): Vision (test with Snellen chart)
CN III (Oculomotor): Pupil constriction, eyelid elevation, most eye movement
CN IV (Trochlear): Downward eye movement
CN VI (Abducens): Lateral eye movement
Mnemonic: “LR6 SO4, all the rest are 3!”
- Lateral Rectus – CN VI
- Superior Oblique – CN IV
- All other eye movements – CN III

Common Eye Conditions

Refractive Disorders

Myopia: Nearsighted
Hyperopia: Farsighted
Presbyopia: Age-related loss of near focus
Astigmatism: Irregular cornea shape
Corrected with glasses, contacts, or LASIK

Cataracts

Cloudy lens = blurry vision
Gradual onset, may see “halos” or glare
Surgery = lens replacement
Nursing Tip: Post-op: No straining, bending, lifting, or rubbing eye

Glaucoma

↑ Intraocular Pressure (IOP) damages optic nerve
Types:
- Open-angle (chronic) – slow, peripheral vision loss
- Angle-closure (acute) – sudden pain, nausea, vision loss = emergency!
Treated with eye drops (beta-blockers, prostaglandins)
Check IOP regularly!

Macular Degeneration

Loss of central vision
Dry: Gradual; no cure
Wet: Sudden; treated with injections (anti-VEGF)
Leading cause of vision loss in older adults

Retinal Detachment

Separation of retina = EMERGENCY
Symptoms: floaters, flashes, curtain over vision
Surgery needed to repair

Eye Tests & Assessments

Snellen Chart: Visual acuity (distance)
Tonometry: Intraocular pressure (for glaucoma)
Pupil Reaction (PERRLA): CN III function
Visual Fields: Peripheral vision
Ophthalmoscope: Internal eye structures
PERRLA: Pupils Equal, Round, Reactive to Light and Accommodation

Memory Tricks

CN Eye Mnemonic: “Two, Three, Four, and Six see the tricks!”
- CN II – See
- CN III, IV, VI – Move the eyes
Pupil Response: “The pupils are the windows to the brain. If they’re unequal, unreactive, or sluggish — something’s wrong!”

Nursing Priorities for Vision Issues

Fall risk precautions
Educate on med adherence (especially eye drops)
Explain surgical prep/post-op (no rubbing, no lifting)
Protect eyes from trauma or light if dilated
Ensure accessibility tools for patients with low vision

Cranial Nerves

Quick List

I Olfactory – Smell like cookies! (Sensory)
II Optic – See the world like a superhero! (Sensory)
III Oculomotor – Move your eyeballs around (Motor)
IV Trochlear – Look at your nose with your eyes (Motor)
V Trigeminal – Feel your face and chew your food (Both)
VI Abducens – Look side to side like you're sneaking (Motor)
VII Facial – Smile, cry, and taste ice cream! (Both)
VIII Vestibulocochlear Hear music and balance like a gymnast (Sensory)
IX Glossopharyngeal Swallow your snacks and taste (Both)
X Vagus Talk, digest food, and keep calm (Both)
XI Accessory Shrug your shoulders like “I don’t know!” (Motor)
XII Hypoglossal Stick out your tongue! (Motor)

Mnemonic for NAMES

"Oh Oh Oh To Touch And Feel Very Green Vegetables AH Heaven"
- Olfactory
- Optic
- Oculomotor
- Trochlear
- Trigeminal
- Abducens
- Facial
- Vestibulocochlear
- Glossopharyngeal
- Vagus
- Accessory
- Hypoglossal

Mnemonic for FUNCTION

“Some Say Money Matters But My Brother Says Big Brains Matter Most”
Nerve # Function
- 1 Sensory
- 2 Sensory
- 3 Motor
- 4 Motor
- 5 Both
- 6 Motor
- 7 Both
- 8 Sensory
- 9 Both
- 10 Both
- 11 Motor
- 12 Motor

Bonus Round – Pretend!

You just smelled a fresh-baked cookie… ➡ That’s Olfactory (I)!
You look at it to make sure it's chocolate chip… ➡ Optic (II)
Your eyes move to follow the cookie as Mom brings it… ➡ Oculomotor (III), Trochlear (IV), and Abducens (VI) all work together!
You feel the cookie in your hand and chew it up… ➡ Trigeminal (V)
You smile because it’s SO GOOD… ➡ Facial (VII)
You hear your brother asking for a bite… ➡ Vestibulocochlear (VIII)
You swallow the last bite and taste some frosting… ➡ Glossopharyngeal (IX)
You talk and say, “That was yummy!” ➡ Vagus (X)
You shrug when asked to share more… ➡ Accessory (XI)
You stick out your tongue to tease… ➡ Hypoglossal (XII)

Practice Activity: Match the nerve to the action:

Seeing stars - Optic (II)
Tasting lemonade - Glossopharyngeal (IX)
Balancing on one foot - Vestibulocochlear (VIII)
Smiling - Facial (VII)
Chewing a burger - Trigeminal (V)
Shrugging shoulders - Accessory (XI)
Smelling flowers - Olfactory (I)

Electrolyte Balance

Basics

Electrolytes = minerals that carry electrical charge.
Functions include:
- Nerve conduction
- Muscle contraction (especially the heart)
- Fluid balance
- Acid-base regulation