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CNS (Central Nervous System) Systemic Examination

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1. Mental Status

• Orientation — to person, place, time, and situation
• Insight and judgment — awareness of illness
• Language and speech — fluency, comprehension, naming, repetition (detect aphasia, dysarthria, dysphonia)
• Memory — short-term and long-term
• Higher cortical functions — attention, calculation, visuospatial ability

More complex functions are tested first; if these are intact, component sub-tests may be unnecessary.

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2. Cranial Nerves (I–XII)

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3. Motor System

a) Inspection

• Muscle wasting (atrophy) or hypertrophy
• Fasciculations — coarse twitching of muscle bundles at rest (suggests LMN disease)
• Involuntary movements — tremor, dystonia, myoclonus, chorea, athetosis, tics

b) Tone

• Passive flexion and extension of joints
• Spasticity (UMN — velocity-dependent, "clasp-knife")
• Rigidity (extrapyramidal — "lead pipe" or "cogwheel")
• Hypotonia (LMN, cerebellar)

c) Power (MRC Grading 0–5)

• Upper limbs: Arms extended in supination with eyes closed → weak arm shows pronator drift (sensitive for corticospinal tract lesion)
• Lower limbs: Hip flexion/extension, knee flexion/extension, ankle dorsiflexion/plantarflexion

d) Pronator Drift Test

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4. Reflexes

Deep Tendon Reflexes (DTRs)

Superficial Reflexes

• Abdominal reflexes (T8–T12): stroke each quadrant — absence suggests UMN lesion ipsilaterally
• Cremasteric reflex (L1–L2): males only
• Plantar response (Babinski sign): stroke lateral sole → normal = plantar flexion of toes; extensor response (Babinski +ve) = UMN lesion

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5. Coordination

• Finger-to-nose (FNT): patient touches own nose then examiner's finger repeatedly — look for intention tremor, dysmetria, past-pointing
• Heel-to-shin (HTS): heel runs along shin from knee to ankle — ataxia suggests cerebellar or sensory pathology
• Rapid alternating movements (RAM): pronation/supination of hands rapidly — dysdiadochokinesis in cerebellar disease
• Tandem gait: walk heel-to-toe in a straight line — ataxia suggests cerebellar or dorsal column disease

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6. Sensory Examination

Primary Modalities

Higher Cortical (Parietal Lobe) Sensory Functions

• Graphesthesia: identify numbers drawn on palm (eyes closed)
• Stereognosis: identify objects placed in hand (eyes closed)
• Two-point discrimination: distinguish two simultaneous points
• Sensory extinction: double simultaneous stimuli — extinction suggests contralateral parietal lobe lesion

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7. Gait and Balance

• Stance, base width, cadence, arm swing
• Specific patterns: hemiplegic gait (circumduction), Parkinsonian gait (shuffling, festination), cerebellar ataxia (broad-based, staggering), sensory ataxia (high-stepping), steppage gait (foot drop)

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8. Signs of Meningeal Irritation

• Neck stiffness: resistance to passive neck flexion
• Kernig's sign: with hip flexed 90°, inability to extend knee >135° = positive
• Brudzinski's sign: passive neck flexion causes involuntary hip flexion = positive

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Summary: UMN vs. LMN Signs

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CNS Systemic Examination — Complete PG-Level Guide

Sources: Harrison's Principles of Internal Medicine 22e; Bradley and Daroff's Neurology in Clinical Practice; Adams and Victor's Principles of Neurology 12e; Goldman-Cecil Medicine; Plum and Posner's Diagnosis and Treatment of Stupor and Coma; Tintinalli's Emergency Medicine; Localization in Clinical Neurology 8e. Frameworks from Hutchinson's Clinical Methods and Archit Boloor's Clinical Skills.

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PRELIMINARY OBSERVATIONS (Before Formal Examination)

• Facial expression: Hypomimia (mask-like face) → Parkinsonism or depression; worried/astonished facies → progressive supranuclear palsy
• Ptosis: Myasthenia gravis, Horner syndrome, CN III palsy, myopathy
• Posture and gait on entry: hemiplegic posture (arm flexed, leg extended), shuffle (PD), ataxic wide-based gait
• Involuntary movements at rest: pill-rolling tremor (PD), hemiballismus, chorea, tics, myoclonus
• Speech: Dysarthria (motor articulation defect), aphasia (language defect), dysphonia (vocal cord)
• Mood and affect: Depression, anxiety, psychosis
• Skin: Café-au-lait spots (NF1), ash-leaf macules (tuberous sclerosis), port-wine stain (Sturge-Weber), telangiectasias (ataxia-telangiectasia), Ehlers-Danlos skin

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COMPONENT 1: MENTAL STATUS / HIGHER CORTICAL FUNCTIONS

Why It Matters

A. Consciousness / Level of Alertness

• Assessed first. Use the Glasgow Coma Scale (GCS) if obtunded: Eye (4), Verbal (5), Motor (6); maximum 15, minimum 3.
• AVPU scale: Alert, Voice-responsive, Pain-responsive, Unresponsive
• Subtle drowsiness: note yawning, poor sustained attention, delayed responses

B. Orientation

1. Time — date, day, month, year, time of day (most sensitive indicator of dysfunction)
2. Place — name of hospital/city
3. Person — self-identification

Disorientation to time first, then place, then person → indicates progressive cortical impairment

C. Attention and Concentration

• Digit span forward: Normal = 7±2 digits. Impaired → delirium, frontal lobe disease
• Digit span backward: Normal = 5±2; more demanding
• Serial 7s: Subtract 7 from 100 repeatedly (100→93→86…) — tests concentration and working memory
• Months of the year backward
• Spell WORLD backward

D. Memory

Bedside: Tell patient: "apple, table, penny" → repeat immediately (registration), then check recall at 5 min

E. Language and Speech

Dysarthria Testing

• "British Constitution" or "baby hippopotamus" → labial sounds (CN VII, orbicularis)
• "Yellow lorry" → lingual sounds (CN XII)
• "Sixty-six" → palatal sounds (CN X)

• Spastic dysarthria: Strained, effortful ("hot potato" voice) → bilateral UMN (pseudobulbar palsy)
• Flaccid dysarthria: Nasal, hypophonic → bulbar palsy (LMN)
• Ataxic dysarthria: Scanning, slurred, explosive syllables → cerebellar
• Hypokinetic dysarthria: Soft, monotone, festinating → Parkinsonism

Aphasia Testing (Dominant Hemisphere — Usually Left)

Key distinction: Paraphasias in Wernicke's — literal (sound substitution: "poon" for spoon) or semantic (word substitution: "fork" for spoon)

F. Visuospatial and Constructional Ability (Non-dominant / Right Parietal)

• Clock drawing test: Draw clock face, place numbers, set hands to 11:10
  • All numbers on one side → hemispatial neglect (right parietal lesion)
  • Poorly organized → constructional apraxia
• Copy intersecting pentagons (from MMSE)
• Draw a house or bicycle

G. Praxis

• Ideomotor apraxia: Inability to perform a learned skilled movement on verbal command despite intact motor and sensory function
  • Test: "Show me how to use a toothbrush", "Wave goodbye"
  • Lesion: Left premotor cortex or corpus callosum

H. Gnosis

• Visual agnosia: Cannot name objects by sight (but can by touch) → occipito-temporal
• Prosopagnosia: Failure to recognize faces → bilateral fusiform gyrus

I. Neglect / Inattention (Non-dominant Parietal)

• Line bisection test: Bisect a horizontal line — neglect patients mark to the right
• Star cancellation test
• Double simultaneous stimulation: Touch both hands simultaneously; patient with parietal lesion extinguishes the contralateral stimulus

J. Frontal Lobe Functions

• Abstract reasoning: Proverb interpretation ("A rolling stone gathers no moss"), similarities/differences
• Executive function: Planning, sequencing, judgment
• Luria's 3-step sequencing test: Fist–Edge–Palm — look for perseveration
• Verbal fluency: Name as many animals as possible in 60 seconds (normal ≥15)

K. Bedside Cognitive Screens

• MMSE (Folstein): 30 points — orientation (10), registration (3), attention (5), recall (3), language (8), construction (1). Score <24 = cognitive impairment
• MoCA (Montreal Cognitive Assessment): 30 points — more sensitive for MCI; scores <26 = impairment

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COMPONENT 2: CRANIAL NERVE EXAMINATION

CN I — Olfactory Nerve

• Anosmia unilateral: Fracture of cribriform plate, olfactory groove meningioma
• Anosmia bilateral: Heavy smoker, sinusitis, Alzheimer's (early sign), Parkinson's (very early)
• Parosmia/Cacosmia: Distorted smell → temporal lobe uncal lesion (uncinate fits — olfactory hallucinations)

NB: Ammonia tests CN V (trigeminal irritant), NOT CN I — do not use it

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CN II — Optic Nerve

1. Visual Acuity

• Use Snellen chart at 6 metres (or 20 feet). Record each eye separately (with best correction).
• Near vision: Jaeger card at 33 cm
• Normal: 6/6 (20/20)
• If reduced: differentiate refractive error (improves with pinhole) vs optic/retinal disease (does not improve)

2. Visual Fields — Confrontation Testing

• Examiner and patient face each other at ~60–90 cm, both at eye level
• Cover one eye. Patient fixes on examiner's nose.
• Wiggle finger in 4 quadrants (superior temporal, inferior temporal, superior nasal, inferior nasal) at periphery
• Screen with both eyes open for hemianopia; test each eye separately for monocular defects

3. Relative Afferent Pupillary Defect (RAPD) — Swinging Flashlight Test

• Swing light between eyes at 2-second intervals in dim light
• Positive RAPD (Marcus Gunn pupil): Pupil paradoxically dilates when light swings to affected eye → indicates optic nerve disease
• Key: tests optic nerve, NOT pupillary reflex pathway

4. Colour Vision

• Ishihara pseudoisochromatic plates (12 or 24): Tests red-green colour discrimination
• Red desaturation: Hold red pin cap in front of each eye — patient reports loss of redness → early optic neuritis

5. Fundoscopy

• Optic disc: Colour (cream/pink), margins (sharp vs blurred), cup-disc ratio (normal <0.5), disc swelling (papilloedema — bilateral; papillitis — unilateral), optic atrophy (pale disc)
• Retinal vessels: AV nicking, copper/silver wiring (hypertension), flame haemorrhages, cotton wool spots, neovascularization
• Macula: Macular degeneration, cherry-red spot (CRAO, storage disorders)

Papilloedema signs: Blurred disc margins start nasally, disc hyperaemia, loss of venous pulsations, later haemorrhages and exudates — indicates raised ICP. No visual loss early.

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CN III, IV, VI — Oculomotor, Trochlear, Abducens

Pupils

• Observe size (normal 3–5 mm), shape, symmetry
• Light reflex: Direct (same eye constricts) and consensual (other eye constricts) — tests CN II (afferent), CN III (efferent)
• Accommodation reflex: Convergence + miosis + lens accommodation when target brought close
• PERRLA: Pupils Equal, Round, Reactive to Light and Accommodation

Eye Movements

• Lateral gaze (CN VI — lateral rectus), medial gaze (CN III — medial rectus), up/out, down/out (CN III), down/in (CN IV — superior oblique)

• Saccades: "Look quickly between my two fingers" — velocity, accuracy
• Pursuit: "Follow my finger slowly" — smoothness; saccadic pursuit = cerebellar/basal ganglia
• VOR: "Keep eyes on my nose while I turn your head" (doll's head manoeuvre)
• Convergence: "Follow my finger to your nose"
• Cover-uncover test: Detects phorias and tropias

• Jerk nystagmus: Fast and slow phases — named by fast phase direction
• Horizontal: Vestibular or cerebellar
• Vertical (upbeat): Cerebellar vermis, brainstem
• Vertical (downbeat): Craniovertebral junction (Arnold-Chiari)
• Pendular: MS, albinism
• Ataxic nystagmus at lateral gaze: INO (large amplitude in abducting eye)

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CN V — Trigeminal Nerve

Sensory

• Test pinprick and light touch in all three divisions on both sides
• Compare left-right symmetry within each division
• Corneal reflex: Touch lateral cornea with cotton wisp → normal = bilateral blink
  • Afferent: CN V (ophthalmic division nasociliary branch)
  • Efferent: CN VII (orbicularis oculi)
  • Reduced/absent → CN V or CN VII lesion (interpret with facial nerve exam)

Motor

• Temporal and masseter muscles: ask patient to clench jaw — palpate muscle bulk, feel symmetry
• Pterygoids: "Open your mouth" — jaw deviates toward the side of CN V motor lesion
• Jaw jerk: tap chin with tendon hammer when jaw slightly open → brisk = bilateral UMN (pseudobulbar palsy), absent = normal

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CN VII — Facial Nerve

Upper vs Lower Motor Neuron Distinction (Clinically Critical)

• "Raise your eyebrows / wrinkle your forehead"
• "Close your eyes tightly" — try to open against resistance (UMN → you can force eyes open; LMN → both possible)
• "Show your teeth / smile" — look for nasolabial fold flattening
• "Puff out your cheeks"
• "Blow out a candle" (circular muscle testing)

• Taste anterior 2/3 tongue via chorda tympani (tested with sugar/salt solution on anterior tongue)
• Secretomotor: Lacrimal, submandibular, sublingual glands

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CN VIII — Vestibulocochlear Nerve

Hearing (Cochlear)

• Gross test: Whisper in each ear at 60 cm while masking other (rub finger in opposite ear)
• Finger rub at each ear

• Normal: Heard equally in both ears
• Lateralizes to AFFECTED ear → Conductive deafness (sound transmitted through bone better than air)
• Lateralizes to NORMAL ear → Sensorineural deafness

• Normal (Rinne positive): AC > BC (air better than bone)
• Rinne negative: BC > AC → Conductive hearing loss
• False negative Rinne: Severe sensorineural loss (vibration crosses skull to better cochlea — BE AWARE)

Vestibular (Vestibular Nerve)

• Romberg test (see below under Gait)
• Dix-Hallpike manoeuvre: For BPPV (benign paroxysmal positional vertigo) — nystagmus with latency and fatigability
• Head thrust test (HIT): Rapid head turn while fixing on target — catch-up saccade = vestibular hypofunction
• Caloric testing: Ice water in ear canal — normal = nystagmus beating away from cold ear ("COWS" — Cold Opposite, Warm Same)

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CN IX, X — Glossopharyngeal and Vagus

• "Open mouth wide, say Ahh" → observe soft palate elevation — should rise symmetrically in midline
• Uvula deviation: Deviates AWAY from the lesion (pulled to normal side) → CN X palsy
• Gag reflex: Touch posterior pharyngeal wall with spatula
  • Afferent: CN IX (glossopharyngeal)
  • Efferent: CN X (vagus)
  • Absence of gag → CN IX/X lesion or cortical depression; presence of gag does not exclude medullary lesion
• Swallowing: Ask patient to swallow — observe for regurgitation, nasal voice, hoarseness
• Voice quality: Hoarseness → recurrent laryngeal nerve (CN X) palsy; Nasal voice → palatal palsy (bilateral)

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CN XI — Accessory Nerve

• Sternocleidomastoid (SCM): "Turn your head to the right" — palpate LEFT SCM contraction (SCM turns head to opposite side). Apply resistance.
• Trapezius: "Shrug your shoulders" — apply downward pressure

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CN XII — Hypoglossal Nerve

• "Stick out your tongue" → observe for:
  • Deviation: Tongue deviates TOWARD the side of LMN lesion (weak side)
  • Atrophy and fasciculations: LMN lesion (MND, skull base tumour)
  • UMN lesion: Tongue deviates to contralateral side, no atrophy, no fasciculations

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COMPONENT 3: MOTOR SYSTEM EXAMINATION

A. Inspection

• Posture at rest: Decorticate (arms flexed, legs extended → hemispheric), decerebrate (all extended → midbrain/pontine)
• Muscle bulk: Atrophy — localized (nerve/root lesion), generalized (LMN, disuse, cachexia); Hypertrophy (dystrophies — pseudohypertrophy in calves in DMD)
• Fasciculations: Fine involuntary muscle twitches visible under skin → LMN lesion (anterior horn cells, nerve root, peripheral nerve); tap over muscle to provoke; benign fasciculations common in gastrocnemius
• Involuntary movements:
  • Tremor: Rest (PD), postural (essential tremor, physiological), intention (cerebellar)
  • Chorea: Irregular, flowing, non-rhythmic, semi-purposeful → Huntington's, rheumatic, Wilson's
  • Athetosis: Slow writhing of distal limbs → basal ganglia
  • Ballismus/Hemiballismus: Flinging proximal limb → subthalamic nucleus
  • Myoclonus: Sudden brief jerks → cortical, subcortical, spinal
  • Dystonia: Sustained muscle contraction producing twisting postures
  • Tics: Stereotyped, semi-voluntary, suppressible

B. Muscle Tone

• Upper limb: Pronate/supinate forearm, flex/extend at wrist and elbow
• Lower limb: Patient supine; examiner's hands behind knee, rapidly lift — normal = heel drags briefly before rising; increased tone = heel lifts immediately

Pendulum test for hypotonia: Let leg swing from edge of table — in hypotonia (cerebellum), pendular swinging continues longer than normal (>2 full swings)

C. Muscle Power — MRC Grading Scale

• Positive: Arm drifts downward AND pronates (corticospinal tract sign)
• Additional observations: Elbow flexion (also UMN), upward drift (contralateral parietal — sensory inattention), finger tremor (sensory ataxia)

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COMPONENT 4: REFLEXES

A. Deep Tendon Reflexes (Stretch Reflexes)

Inverted supinator reflex: Tapping radial styloid causes finger flexion instead of supination → C5/C6 root lesion

B. Plantar (Babinski) Reflex

• Use orange stick / key / thumbnail
• Technique: Stroke lateral surface of sole from heel to ball of foot, then sweep medially across the metatarsal heads (Harpoon sign)
• Normal: Plantar flexion of big toe ± slight flexion of other toes
• Babinski sign (extensor plantar): Extension (dorsiflexion) of big toe + fanning/abduction of other toes → UMN lesion (corticospinal tract)

• Chaddock: Stroke below lateral malleolus
• Oppenheim: Knuckle pressure down tibia
• Gordon: Squeeze calf
• Schafer: Squeeze Achilles tendon
• Bing: Prick dorsum of foot

C. Superficial (Cutaneous) Reflexes

• Abdominal reflex: Stroke each quadrant of abdomen toward umbilicus with orange stick. Umbilicus moves toward stimulus.
  • Upper (T8–T10), lower (T10–T12)
  • Absent ipsilaterally → ipsilateral UMN lesion; absent bilaterally → bilateral UMN lesion
  • Very useful for detecting T-level in spinal cord lesions
• Cremasteric reflex: Stroke upper inner thigh in males → ipsilateral testicular elevation (L1–L2)
• Anal reflex: Scratch perianal skin → contraction of external anal sphincter (S3–S4); absent → cauda equina lesion

D. Primitive / Frontal Release Signs

• Grasp reflex: Stroke palm between thumb and index finger → patient involuntarily grasps examiner's fingers
• Palmomental reflex: Scratch thenar eminence diagonally → contraction of ipsilateral mentalis muscle (chin wrinkle)
• Sucking/rooting reflex: Light touch of lips → sucking/rooting movements
• Snout reflex: Tap upper lip → protrusion of lips
• Glabellar tap: Tap between eyebrows — normal person adapts (blink stops after 2–3 taps); Parkinsonism: continues blinking (Myerson's sign)

E. Clonus

• Ankle clonus: Sharply dorsiflex foot and hold — rhythmic 3–6 Hz oscillations = UMN sign
• Patellar clonus: Push patella sharply downward and hold
• Sustained clonus (>5 beats) is pathological

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COMPONENT 5: SENSORY EXAMINATION

"The sensory exam is the most unreliable part of the neurological examination — it depends heavily on patient cooperation and examiner technique." — Harrison's

1. Test primary sensory modalities first; higher (cortical) only if primary intact
2. Test distally first (where deficits usually appear first in neuropathies)
3. Always compare left vs right, proximal vs distal
4. Test with eyes closed
5. Use random sequence to avoid anticipatory responses

A. Spinothalamic Tract (Anterolateral System)

Pain (Pinprick)

• Use new disposable pin (never reuse — infection risk)
• Touch dorsum of foot, dorsum of hand
• Ask: "Does this feel sharp or blunt? Is it the same on both sides?"
• Hypoalgesia: Reduced pain; Hyperalgesia: Increased pain; Allodynia: Pain from non-painful stimulus
• Map level in spinal cord lesions: test from below lesion upward until sensation changes

Temperature

• Use cold tuning fork (metal at room temperature) or tubes of warm (40°C) and cold (20°C) water
• Especially useful in syringomyelia (dissociated sensory loss — pain/temperature lost, proprioception/vibration preserved)

B. Dorsal Column — Medial Lemniscus System

Vibration

• 128 Hz tuning fork (not 256 Hz — too high frequency, not felt well)
• Strike fork, apply to bony prominence — interphalangeal joint of big toe, then ankle (medial malleolus), then knee, then iliac crest if absent distally
• Ask patient: "Can you feel the vibration? Tell me when it stops."
• Biothesiometer for quantitative testing
• Absent distally: Peripheral neuropathy, dorsal column disease

Proprioception (Joint Position Sense — JPS)

• Grasp the distal phalanx of the big toe laterally (to avoid touch cues)
• Move 1–2 mm up or down (small excursion is sufficient with intact JPS)
• Ask: "Is it going up or down?" Eyes closed
• Normal: Correctly identifies even 1 mm movement
• If impaired: Test more proximally (ankle, knee, hip)
• JPS loss → Romberg positive, sensory ataxia, Waddling/stamping gait

Light Touch

• Carried by BOTH spinothalamic and dorsal columns
• Use wisp of cotton or fingertip; apply with minimal pressure
• Ask patient to say "Yes" when they feel touch

C. Cortical Sensory Functions (Parietal Lobe)

D. Important Sensory Patterns

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COMPONENT 6: COORDINATION EXAMINATION

A. Upper Limb Tests

Finger-Nose Test (FNT)

• Ask patient to touch own nose with index finger, then touch examiner's outstretched finger, repeatedly
• Move examiner's finger to different positions with each touch
• Observe:
  • Dysmetria: Past-pointing — overshoots or undershoots target
  • Intention tremor: Tremor that increases as finger approaches target (cerebellar)
  • Normal: Smooth, accurate, no tremor

Finger-Nose-Finger Test

Dysdiadochokinesis (DDK)

• "Tap your thigh alternately with palm and back of hand as fast as possible"
• Or: Rapid pronation-supination of forearm
• Dysdiadochokinesis: Irregular, slowing, variable amplitude → ipsilateral cerebellar hemisphere lesion

Rebound Phenomenon (Stewart-Holmes Sign)

• Patient flexes elbow against resistance; examiner suddenly releases → normal: slight overshoot then stop; cerebellar: excessive rebound, arm flails up (failure of check mechanism)

B. Lower Limb Tests

Heel-Knee-Shin (HKS)

• Patient supine, eyes open/closed
• Place heel on opposite knee, slide heel down shin to ankle, lift and repeat
• Ataxia of HKS → ipsilateral cerebellar lesion
• Made worse by closing eyes → sensory (posterior column) ataxia in addition

Foot Tapping

• Tap foot on examiner's hand as rapidly as possible → irregular tapping = cerebellar

C. Gait-Coordination Tests

• Tandem gait (heel-to-toe): Walk along a straight line — ataxia is amplified
• Walking on heels: Tests dorsiflexors (L4–L5) and cerebellum
• Walking on toes: Tests plantarflexors (S1–S2)

Cerebellar Signs — DANISH Mnemonic

• Dysdiadochokinesis
• Ataxia (gait and limb)
• Nystagmus (horizontal, ipsilateral beating)
• Intention tremor
• Scanning (ataxic) dysarthria
• Hypotonia + Heel-shin ataxia

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COMPONENT 7: GAIT EXAMINATION

"Watching the patient walk is the most important part of the neurological examination." — Harrison's Principles of Internal Medicine 22e

Observation

• Observe from front, side, and behind
• Assess: Initiation, base width, stride length, cadence, arm swing, turning, posture

Classic Gait Patterns

Romberg Test

Clinically: Romberg positive + absent ankle jerks + loss of vibration → Subacute combined degeneration (Vit B12), Tabes dorsalis, CIDP

Pull Test (Postural Stability)

• Stand behind patient, warn them, then pull firmly backward by shoulders
• Normal: 1 retropulsive step to regain balance
• Abnormal: Multiple shuffling steps, inability to recover, or falls → Parkinsonism (loss of postural reflexes)

Tandem Gait

• Walk heel-to-toe along straight line for 5–10 steps
• Sways/steps out → cerebellar or vestibular

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COMPONENT 8: SIGNS OF MENINGEAL IRRITATION

Neck Stiffness

• Patient supine, examiner places hand behind head and attempts passive flexion
• Resistance to flexion = meningism (but NOT rotation or lateral flexion — distinguishes from cervical spondylosis)

Kernig's Sign

• Patient supine, flex hip to 90°, then extend knee
• Positive: Pain and resistance to knee extension beyond 135° → meningeal irritation (hamstrings in spasm)

Brudzinski's Sign

• Passive flexion of neck → involuntary flexion of hips and knees
• Positive: Both hips and knees flex reflexly → meningeal irritation

Jolt Accentuation

• Patient rotates head horizontally at 2–3 Hz
• Worsening of headache = positive → more sensitive than neck stiffness for bacterial meningitis

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COMPONENT 9: AUTONOMIC EXAMINATION

• Postural BP: Take BP lying and standing; orthostatic hypotension = fall of ≥20 mmHg systolic or ≥10 mmHg diastolic within 3 minutes of standing → autonomic neuropathy (DM, MSA, Parkinson's), hypovolaemia
• Heart rate variability: With deep breathing at 6 breaths/min — R–R variation <10 bpm = autonomic dysfunction
• Sweating: Anhidrosis distal → postganglionic sympathetic; widespread → central
• Bladder/bowel/sexual function: Ask about incontinence, retention, erectile dysfunction
• Pupillary responses: Already assessed (sympathetic/parasympathetic balance)

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COMPONENT 10: SIGNS FOR LOCALIZATION (PG PEARLS)

Localization Summary Table (Harrison's, Table 433-1)

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UMN vs LMN Comparison (Hutchinson's Framework)

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APPENDIX: Order of CNS Examination in Clinical Practice

1. General inspection + observation on entry
2. Mental status / Higher cortical functions
3. Speech and language
4. Cranial nerves I–XII (in numerical order; group III/IV/VI)
5. Motor system: Inspection → Tone → Power
6. Reflexes: Biceps → Supinator → Triceps → Knee → Ankle → Plantars → Abdominales → Clonus
7. Coordination: FNT → DDK → HKS
8. Sensory: Spinothalamic (pain, temp) → Dorsal columns (vibration, JPS) → Cortical (stereognosis, graphesthesia, extinction)
9. Gait: Spontaneous → Heel → Toe → Tandem → Romberg → Pull Test
10. Meningeal signs (if indicated)
11. Autonomic signs (if indicated)

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