Comprehensive Textbook Chapter — Neuroanatomy, Assessment, Disorders & Nursing Care
Neurons: Transmit impulses. Have cell body (gray matter), dendrites (receive impulses), and one axon (transmits impulses). Myelin sheath speeds impulse transmission. Synapse = space between neurons containing neurotransmitters. Acetylcholine receptor sites on post-synaptic neurons capture impulses.
Glial Cells (Neuroglia): Supportive cells that nourish/oxygenate neurons and produce myelin. Types: astrocytes, oligodendrocytes, Schwann cells, ependymal cells, microglial cells.
Neuron classification: Afferent (sensory), Efferent (motor), Interneurons.
The CNS includes the brain and spinal cord.
Outer cortex (gray matter) + inner medulla (white matter). Two hemispheres, each with 4 lobes:
Corpus callosum connects the hemispheres. Basal ganglia (islands of gray matter within white matter) are part of the extrapyramidal system — maintain muscle tone and control body movement. Substantia nigra = dopamine-producing cells in basal ganglia.
Coordinates muscle tone, voluntary movements, and maintains equilibrium.
Connects cerebrum and brain stem. Contains thalamus (relay station for pain, temperature, touch; controls emotional responses — anger/fear) and hypothalamus (controls BP, temperature, sleep, food/water intake; control center for pituitary and ANS).
Contains midbrain, pons, and medulla oblongata. Has vital centers for respiration, cardiac function, and vasomotor control.
Extends from foramen magnum to L₂ (conus medullaris → cauda equina). H-shaped gray matter surrounded by white matter:
Meninges: Pia mater (inner), Arachnoid membrane (middle), Dura mater (outer). Subarachnoid space (between pia and arachnoid) contains CSF.
Ventricles: 4 cavities within brain — 2 lateral (in hemispheres), 3rd (diencephalon), 4th (brain stem → central canal of spinal cord). CSF produced by choroid plexus in lateral and 3rd ventricles; circulates through all ventricles and central canal; absorbed into venous system.
Blood supply: 2 internal carotid arteries (anterior) + 2 vertebral arteries (posterior) → basilar arteries → Circle of Willis.
C-7, T-12, L-5, S-1 (sacral), C-1 (coccyx). 31 pairs of spinal nerves: C-8, T-12, L-5, S-5, C-1.
Mnemonic: OOO, TTAF, VGV, AH
| # | Name | Function | Test |
|---|---|---|---|
| I | Olfactory | Smell | Smell non-irritating substance (coffee, tobacco) with eyes closed |
| II | Optic | Vision | Snellen's/Allen's chart |
| III | Oculomotor | Pupil constriction, eyelid raising | Look up/down/inward; penlight to eyes |
| IV | Trochlear | Downward & inward eye movement | Follow finger down & in |
| V | Trigeminal | Facial sensation, jaw movement, corneal reflex | Pin/wisp of cotton on face; bite down |
| VI | Abducens | Lateral eye movement | Follow finger in all directions |
| VII | Facial | Facial movement; taste anterior ⅔ of tongue | Frown, smile, puff cheeks; sweet/sour/bitter on tongue |
| VIII | Vestibulocochlear | Hearing & balance | Weber, Rinne, Romberg tests |
| IX | Glossopharyngeal | Swallowing; taste posterior ⅓ of tongue | Gag reflex; swallow secretions |
| X | Vagus | Swallowing & speaking | Say "ah" — uvula midline; voice quality |
| XI | Spinal Accessory | Shoulder shrug, head rotation | Shrug against resistance |
| XII | Hypoglossal | Tongue movement | Stick tongue out, move side to side |
Controls automatic functions (CV, GI motility, glandular activity).
| Effector Organ | Sympathetic (Adrenergic / Fight or Flight) | Parasympathetic (Cholinergic / Rest & Digest) |
|---|---|---|
| Eyes | Mydriasis (dilation) | Miosis (constriction) |
| Lacrimal glands | ↓ secretions (dry eyes) | Stimulates secretions |
| Salivary glands | ↓ secretions (dry mouth) | Copious, thin, watery |
| Heart | ↑ HR & force of contraction | ↓ rate |
| Respiratory | Bronchodilation | Bronchoconstriction |
| GI tract | ↓ peristalsis, constricts sphincters, ↓ secretions | ↑ peristalsis, relaxes sphincters, stimulates secretions |
| Liver | Glycogen → glucose | ↑ bile release |
| Adrenal gland | Stimulates epinephrine/norepinephrine | No effect |
| Urinary tract | Relaxes detrusor, contracts trigone | Contracts detrusor, relaxes trigone |
Glasgow Coma Scale (GCS): Objective assessment of consciousness. Score 3–15.
| Eye Opening (E) | Score | Verbal Response (V) | Score | Motor Response (M) | Score |
|---|---|---|---|---|---|
| Spontaneous | 4 | Oriented | 5 | Obeys commands | 6 |
| To voice | 3 | Confused | 4 | Localizes pain | 5 |
| To pain | 2 | Inappropriate words | 3 | Withdrawal (normal flexion) | 4 |
| No response | 1 | Incomprehensible sounds | 2 | Abnormal flexion (decorticate) | 3 |
| None | 1 | Extension (decerebrate) | 2 | ||
| No response (flaccid) | 1 |
Pupils Equal, Round, Reactive to Light and Accommodation. Tests size, shape, equality, and reaction to light. Accommodation = the eye's ability to change optical power to maintain focus as distance changes.
Eyes move opposite to head direction. Normal = dolls eye present. If eyes stay fixed = dolls eye negative (brain stem injury). Contraindicated in suspected cervical spine injury.
HOB elevated 30°. Cold/warm water instilled into auditory canal. Expected: conjugate eye movement toward irrigated side, then rapid opposite. Absent/dysconjugate = brainstem damage.
| Test | Purpose | Nursing Care |
|---|---|---|
| Lumbar Puncture | Measure CSF pressure, obtain CSF specimen. Contraindicated in ↑ICP. | Pre: empty bladder, lateral recumbent position. Post: flat 6–24 hours, force fluids, check puncture site, assess sensation/movement in lower extremities. |
| EEG | Record electrical brain activity; detect seizure focus | Pre: withhold anticonvulsants/sedatives 2–3 days, shampoo hair. Post: remove electrode paste with acetone, shampoo. |
| CT Scan | Scan brain/spinal cord in successive layers | May use contrast; withhold fluids before contrast study. |
| MRI | Identify intracranial/spinal abnormalities | Contraindicated: pacemaker, surgical clips, metal implants. Remove jewelry, glasses, nitroglycerine patches. Ear plugs. Sedation if claustrophobic. |
| PET Scan | 3D functional imaging | Detects gamma rays from positron-emitting radionuclide. |
| Cerebral Angiography | Visualize cerebral vessels via dye injection | Post (if carotid used): monitor neck swelling, difficulty swallowing/breathing. |
ICP = brain mass + CSF + blood flow within brain. Normal: 5–15 mmHg or 60–180 mm H₂O.
Early signs: Restlessness, confusion, disorientation, headache, projectile vomiting, ipsilateral pupil dilation with sluggish reaction (eventually fixed/dilated).
Late signs (Cushing's triad): Widening pulse pressure, bradycardia, Cheyne-Stokes respirations. Also: ↑ temp, papilledema, contralateral hemiparesis, positive Babinski, posturing, seizures, coma.
Management: Osmotic diuretics (mannitol), loop diuretics (Lasix), corticosteroids (dexamethasone), anticonvulsants (phenytoin), stool softeners, antiemetics. Nursing: patent airway, hyperventilation (hypocapnia → vasoconstriction → ↓ ICP), limit suctioning to < 10 seconds, avoid clustering care, HOB elevated 15°, head/neck neutral, quiet environment, fluid restriction 1200–1500 mL.
Temp ≥ 41°C (106°F). Caused by hypothalamic dysfunction. Increases cerebral metabolism → seizure risk. Manage: room temp 70°F, antipyretics, tepid sponge bath, hyperthermia blanket (check temp hourly, turn off 1° above desired, prevent shivering).
Pathophysiology: Destruction of brain cells due to reduced cerebral blood flow and hypoxia (5–10 min → irreversible infarction).
Risk factors: HTN, DM, MI, arteriosclerosis, chronic A-fib, valve replacement, obesity, smoking, stress, OCPs.
Types: Ischemic (thrombotic or embolic) vs. Hemorrhagic.
Stages: TIA → stroke in evolution → completed stroke.
S/S — Warning signs (FAST): Facial drooping, Arm weakness, Speech difficulty, Time to call 911.
General findings: ↓ LOC, headache, N/V, seizures, nuchal rigidity, fever, HTN, slow bounding pulse, Cheyne-Stokes respiration, contralateral hemiplegia, homonymous hemianopsia, facial droop, ataxia, dysphagia, bowel/bladder dysfunction, dysarthria, agnosia, apraxia, neglect syndrome.
Right brain damage: Left hemiplegia, disorientation, impulsive, safety problems, impaired time, short attention span, short-term memory loss.
Left brain damage: Right hemiplegia, aphasia, slow/cautious behavior, aware of deficits (depression, labile mood).
Diagnostics: CT, MRI, EEG, cerebral arteriography.
Medical Management: Osmotic agents, corticosteroids, anticonvulsants, antihypertensives, anticoagulants (heparin, warfarin, aspirin, clopidogrel). Thrombolytics (t-PA) within 3–6 hours in selected cases.
Nursing Care: Patent airway, monitor for ↑ICP/shock/hyperthermia/seizures. Fluid restriction to decrease edema. HOB 15°. T&P q2h (20 min on affected side). Quiet environment.
Rehab — Hemiplegia: Position/prevent deformities (foot drop, external rotation, wrist drop). Support paralyzed arm in pillow or sling. Transfer to unaffected side.
Dysphagia: Check gag reflex before feeding. Upright position. Place food in unaffected side. Soft foods, modified liquids. Flex neck to chest to swallow.
Homonymous hemianopsia: Approach on unaffected side. Place belongings on unaffected side. Teach scanning.
Aphasia — Receptive: Simple slow directions, one command at a time, nonverbal communication.
Aphasia — Expressive: Listen carefully, anticipate needs, allow time to answer, picture/communication board.
Brief period of neurological deficit (visual loss, hemiparesis, slurred speech, aphasia, vertigo) lasting < 30 minutes. Warning sign of impending stroke. Management: antiplatelet therapy, risk factor modification.
Pathophysiology: Uncontrolled firing of electrical impulses by neurons. Epilepsy = chronic recurrent seizures.
Causes: 75% unknown. Structural lesions, electrolyte imbalance, hypoglycemia, infection (meningitis, encephalitis), lead poisoning, Reye's syndrome, intracranial hemorrhage.
Types: Grand mal (tonic-clonic): aura → tonic (stiffen, 20–40 sec) → clonic (repetitive movements) → coma (postictal). Absence (petit mal): blank stare 5–10 sec. Status epilepticus: grand mal prolonged & unresponsive to treatment (emergency).
Diagnosis: EEG, CT, MRI, LP, blood studies.
Medications: Phenytoin (Dilantin), phenobarbital, valproic acid, carbamazepine, levetiracetam (Keppra), topiramate, lamotrigine, gabapentin.
Nursing: Protect from injury (prevent falling, padded side rails). Do not restrain. Do not use tongue blades. Side-lying position. Suction mucus. Observe/record seizure phases. Identify triggers.
Pathophysiology: Degeneration of dopamine-producing neurons in substantia nigra (basal ganglia). Disorder of the extrapyramidal system.
S/S: Pill-rolling tremors, cogwheel rigidity, bradykinesia, stooped posture, masklike face, monotonous speech/echolalia, dementia, drooling, cramped writing, autonomic symptoms (sweating, seborrhea, constipation).
Medications: Levodopa (L-dopa), carbidopa-levodopa (Sinemet), amantadine, bromocriptine, selegiline. Anticholinergics: benztropine (Cogentin), trihexyphenidyl (Artane). COMT inhibitors: entacapone (Comtan).
Nursing: Safe environment (hand rails, low-heeled shoes, no scatter rugs). Rock back and forth to initiate movement. Speech therapy. Cut food into small pieces. High-fiber diet, fluids 2000 mL/day. Firm mattress, small pillow. Broad-based gait. Daily exercise.
Pathophysiology: Autoimmune demyelination of CNS neurons. Intermittently progressive with remissions/exacerbations.
S/S: Blurring, diplopia, scotomas. Sensory dysfunction (touch, pain, temperature, position). Motor: weakness, paralysis, spasticity. Cerebellar: ataxia, scanning speech, nystagmus. Bladder: retention/incontinence. Constipation, sexual dysfunction.
Diagnosis: CT/MRI (demyelination), CSF (↑ protein, ↑ immunoglobulin), EEG (delayed VER).
Management: Corticosteroids (Solu-Medrol), interferon beta-1a (Avonex), plasmapheresis. For spasticity: baclofen, dantrolene, diazepam. Bladder: bethanechol (retention), oxybutynin (incontinence).
Nursing: Prevent UTI: 3000 mL fluid/day, acid-ash diet. Wide-based gait, ROM, assistive devices. Test bath water, avoid heating pads. Frequent position changes. Psychological support.
Pathophysiology: Autoimmune disease affecting motor neurons of anterior horn cells and brainstem. Does NOT affect sensory or autonomic systems. Onset 40–70 years.
S/S: Fatigue, muscle weakness, atrophy (arms, trunk, legs), tongue atrophy, dysphagia, dysarthria, fasciculations. Progression → flaccid quadriplegia → respiratory failure (2–6 years).
Management: Riluzole (Rilutek) — neuroprotector extends life by months. Symptomatic: ventilation support, chest PT, prevent immobility complications, promote independence.
Pathophysiology: Autoimmune peripheral polyneuritis; often preceded by viral infection or immunization → immune over-reactivity → demyelination of peripheral nerves. Ascending paralysis. Progression stops by 4 weeks; recovery 3–6 months.
S/S: Sensory changes, clumsiness, symmetrical bilateral ascending paralysis, dysphagia, ventilation insufficiency, absent deep tendon reflexes, autonomic dysfunction.
Diagnosis: CSF ↑ protein, EMG ↓ nerve conduction.
Management: Corticosteroids, immunoglobulins, plasmapheresis.
Nursing: Maintain adequate ventilation, check individual muscle groups q2h in acute phase, check gag reflex/swallowing/voice. Foot cradle for comfort.
Pathophysiology: Autoimmune — antibodies destroy acetylcholine receptors at neuromuscular junction → disturbed impulse transmission → extreme muscle weakness (voluntary muscles). Weakness ↑ with activity, ↓ with rest.
S/S: Ptosis, diplopia, masklike face, dysphagia, weak voice, hoarseness, respiratory paralysis.
Diagnosis: Tensilon test (IV edrophonium → immediate relief for 5–10 min), EMG (↓ amplitude), anti-ACh receptor antibodies.
Management: Anticholinesterases: neostigmine (Prostigmin), pyridostigmine (Mestinon). Corticosteroids, immunoglobulins. Thymectomy. Plasmapheresis.
Nursing: Meds exactly on time. Give with milk/crackers. Check muscle strength and breathing before/after meds. Avoid CNS depressants, aminoglycosides, procainamide. Give meds 30 min before meals. Check gag reflex. Keep emergency airway & suction nearby.
Crisis differentiation: Myasthenic crisis (under-medication — improves with Tensilon) vs. Cholinergic crisis (overmedication — worsens with Tensilon). Keep atropine available.
Pathophysiology: Inflammation of meninges (bacterial, viral). Organisms reach CNS from sinuses, mastoid, ear, skull fracture, or via blood/CSF/lymph.
S/S: Headache, photophobia, irritability, vomiting, high fever/chills. Signs of meningeal irritation: nuchal rigidity, Kernig's sign, Brudzinski sign, opisthotonos. Possible seizures, ↓ LOC, hydrocephalus.
Diagnosis (LP): ↑ protein, ↓ sugar, ↑ CSF pressure, cloudy appearance.
Management: Large doses of antibiotics based on C&S. Care for ↑ICP, seizure, hyperthermia. Quiet/dark room. High-protein, high-calorie diet. Respiratory isolation for meningococcal meningitis.
Inflammation of brain (viral — arbovirus, West Nile, HSV-1, or complication of mumps/measles/chickenpox). S/S: Headache, fever, chills, vomiting, altered LOC, meningeal signs, seizures. Management: treat ↑ICP, seizures, hyperthermia.
Mechanisms: Coup (primary impact) vs. Contrecoup (secondary impact). Types: concussion (temporary neural dysfunction, no structural damage), contusion (bruising), hemorrhage (epidural, subdural, subarachnoid, intracerebral), fractures.
S/S of hemorrhage: Headache, vomiting, ipsilateral pupil dilation, altered LOC, hemiplegia. Epidural: most serious, rapid accumulation of blood.
Fracture signs: CSF otorrhea/rhinorrhea, Battle's sign (mastoid ecchymosis), Raccoon sign (periorbital ecchymosis).
Management: No sedatives. Patent airway. Monitor VS/neuro checks. CSF leak: don't clean nose/ears without MD order, HOB 30°, prophylactic antibiotics. Otorrhea: cotton ball in ear. Rhinorrhea: sterile gauze at nose.
Level-based findings: Above C4 → respiratory paralysis (phrenic nerve). C1–C8 → quadriplegia. T1–L4 → paraplegia. Above T6 → autonomic dysreflexia.
Spinal shock: Areflexia below lesion, flaccid paralysis (becomes spastic when reflex returns), hypotension + bradycardia, urinary/fecal retention, paralytic ileus, lack of sweating.
Emergency: ABCs, jaw thrust (if airway obstructed), immobilize in position found, cervical collar + spinal board, suction available.
Management: Immobilization (Stryker frame, halo traction, cervical tongs), surgery (decompression laminectomy, spinal fusion).
Autonomic dysreflexia: Severe headache, hypertension, bradycardia, sweating, goose bumps, blurred vision. Management: sit patient up, check bladder/bowel, reposition, antihypertensives.
Dilation of cerebral artery wall → sac-like outpouching. May rupture → hemorrhage. Clot forms at bleeding site → fibrinolysis by 7–10 days → re-bleeding risk.
S/S: Severe headache, eye pain, ptosis, diplopia, tinnitus, dizziness, ↓ LOC, hemiparesis, seizures.
Management: Antihypertensives, corticosteroids, anticonvulsants, stool softeners, aminocaproic acid (Amicar). Surgical: aneurysm clips or coils.
Nursing: HOB 20–30°, quiet/dark environment, no coughing/sneezing/straining, suction only with order, fluid restriction, seizure precautions.
Dexamethasone (Decadron), methylprednisolone (Solu-Medrol). Used to reduce cerebral/spinal edema and inflammation in MS, brain tumors, spinal cord injury.
| Condition | Key Features | Management |
|---|---|---|
| Hydrocephalus | ↑ head circumference, bulging fontanels, setting-sun eyes, Macwen sign (cracked pot sound) | VP/VA shunt; position on unoperative side; monitor for ↑ICP, infection |
| Spina Bifida (Myelomeningocele) | Sac with fluid + nerves; paralysis below lesion, neurogenic bowel/bladder, latex allergy risk | Surgical closure within 48h; prone position; sterile NS-soaked dressing; intermittent catheterization |
| Reye's Syndrome | Encephalopathy + fatty liver from ASA toxicity after viral illness; sudden vomiting, listlessness, seizures, coma | Emergency; manage ↑ICP; NO ASPIRIN for children with viral illnesses |
| Cerebral Palsy | Motor dysfunction (spasticity, athetosis, ataxia, rigidity); may have MR, hearing/vision/speech deficits | Multidisciplinary; spasticity management; safety helmet; customized feeding; ROM exercises |
| Febrile Seizures | 5% of children <5 years; occurs as fever rises; non-progressive; EEG normal after 2 weeks | Antipyretics; treat underlying infection; seizure precautions |