Neuroanatomy and Clinical Assessment: Cranial Nerves, CNS Changes, and Neuro Tests

CN I Olfactory

Sense of smell. (Sensory)

CN II Optic

Vision (visual acuity and visual fields). (Sensory)

CN III Oculomotor

Moves most eye muscles, raises eyelid, constricts pupils, and controls lens focusing. (Motor)

CN IV Trochlear

Moves eye downward and inward (controls superior oblique muscle). (Motor)

CN V Trigeminal

Provides facial sensation and controls muscles used for chewing. (Both)

CN VI Abducens

Moves eye laterally (away from midline). (Motor)

CN VII Facial

Controls facial expressions, taste from anterior 2/3 of tongue, and secretion of saliva and tears. (Both)

CN VIII Vestibulocochlear

Hearing and balance (equilibrium). (Sensory)

CN IX Glossopharyngeal

Taste from posterior 1/3 of tongue, swallowing, and sensory part of gag reflex. (Both)

CN X Vagus

Controls parasympathetic activity of heart, lungs, and digestive organs; also involved in swallowing and speech. (Both)

CN XI Accessory

Controls head turning and shoulder shrug (sternocleidomastoid and trapezius muscles). (Motor)

CN XII Hypoglossal

Controls tongue movement for speech and swallowing. (Motor)

Central Nervous System

Right brain stroke → Left motor/sensory deficits; Left brain stroke → Language deficits.

Wernicke's area

Receptive aphasia (can't understand).

Broca's area

Expressive aphasia (can't speak words).

Cranial Nerves

12 pairs; Know names, functions, and how to test.

Older Adults — CNS Changes

↓ Brain volume; ↓ Myelinated axons; ↓ Sensation; Mobility issues; Cognitive slowing.

Urgent Neuro Assessment

Red Flags: Acute mental status change, Unexplained LOC change, Seizures, Posturing, Unequal pupils, New unilateral weakness/paralysis.

Glasgow Coma Scale

Eye + Verbal + Motor; 15 = normal; <8 = coma; 3 = unresponsive.

Posturing

Decorticate → flexion (above brainstem); Decerebrate → extension (brainstem damage, worse).

Abbreviated Acute Neuro Exam

LOC (GCS), Pupils, Strength, Sensation; If unconscious: EOMs, gag, corneal reflex.

Subjective Data

PMH, Medications, Family history, Risk factors, Neuro symptoms (headache, weakness, tremors, dizziness, speech issues).

Health Promotion

Primary: prevent disease; Secondary: early detection; Tertiary: reduce complications.

Common Symptoms

Headache, Weakness, Tremors, Balance issues, Dizziness, Dysphagia, Cognitive changes, Sensory changes.

Older Adults — Risk Factors

HTN, Atrial fibrillation, Diabetes, CHF, Renal disease, Prior stroke, Falls.

Objective Neuro Assessment

LOC, Cognitive function, Speech/language, Pupils, CN testing, Motor, Cerebellar, Sensory, Reflexes.

Older Adults — CNS Atrophy

↓ Brain weight; ↓ Nerve cells; Slower memory; Slower reflexes.

Diagnostics & Nursing Care

CT/MRI, EEG, Lumbar puncture; Nursing outcomes: Protect affected side, Improve motor function.

Stroke Prevention

Teach: Smoking cessation, BP control, Diabetes control, Exercise, Healthy diet.

Romberg Test

Feet together, arms at sides; Eyes open → closed; Swaying both times = vestibulocerebellar dysfunction.

Neuro Assessment Components

LOC, Mini-Mental, Muscle tone, Strength, Coordination, Rapid movements, Babinski.

Sequence of Neuro Exam

Mental status, Cranial nerves, Motor/cerebellar, Sensory, Reflexes.

Hydrocele

Fluid-filled scrotal swelling.

Inguinal Hernia

Intestine protrudes through inguinal canal.

Muscle Strength Scale

5/5 = full ROM + full resistance; 4/5 = full ROM + moderate resistance; 3/5 = full ROM against gravity; 2/5 = ROM with joint supported; 1/5 = muscle contraction only; 0/5 = no contraction.

Phalen Test

Wrists flexed 90° for 60 sec; Positive = numbness/burning → carpal tunnel.

Fall Risk

Morse Fall Scale, Hendrich II Fall Risk Model.