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I have practical on tomorrow 8:30mroning can u help me go through this
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Here is your complete revision guide for Practical I - CNS Clinical Examination (15 marks) + Clinical Case Chart (5 marks). Study this tonight and you'll be well-prepared!
PRACTICAL I - CNS EXAMINATION REVISION GUIDE
OVERVIEW
- 15 marks: Clinical examination (Sensory / Motor / Reflexes / Cranial Nerve)
- 5 marks: Clinical case history chart
- Approach every patient examination in a systematic order: inspection → tone → power → reflexes → coordination → sensation → cranial nerves
PART 1: MOTOR EXAMINATION
A. Inspection
Look for:
- Muscle atrophy or hypertrophy
- Fasciculations (small involuntary twitches - suggests LMN lesion)
- Involuntary movements at rest (tremor, tics, chorea)
B. Muscle Tone
Test by passive movement of a relaxed limb:
- Upper limbs: Pronate/supinate forearm, flex/extend wrist
- Lower limbs: Patient supine, place hands behind knees and quickly raise them
- Normal: Heel drags briefly before rising
- Increased tone: Heel lifts immediately
| Type of Increased Tone | Character | Lesion |
|---|---|---|
| Spasticity | Velocity-dependent resistance | Corticospinal tract (UMN) |
| Rigidity | Equal resistance in all directions | Extrapyramidal (basal ganglia) |
| Cogwheel rigidity | Jerky interrupted resistance | Parkinsonism |
| Paratonia | Fluctuating resistance | Frontal lobe |
C. Muscle Power (MRC Grading)
| Grade | Description |
|---|---|
| 0 | No movement |
| 1 | Flicker/trace contraction, no joint movement |
| 2 | Movement with gravity eliminated |
| 3 | Movement against gravity, NOT against resistance |
| 4 | Movement against resistance (mild to strong: 4-, 4, 4+) |
| 5 | Full normal power |
Pronator Drift Test (quick screening): Ask patient to hold both arms extended, palms up, eyes closed for 10 seconds. Pronation or downward drift = UMN weakness.
D. UMN vs LMN - Key Differences
| Feature | UMN Lesion | LMN Lesion |
|---|---|---|
| Tone | Increased (spasticity) | Decreased (flaccidity) |
| Power | Reduced | Reduced |
| Reflexes | Exaggerated | Absent/reduced |
| Babinski | Positive | Negative |
| Fasciculations | Absent | Present |
| Atrophy | Minimal (late) | Prominent (early) |
PART 2: SENSORY EXAMINATION
Always test both sides and compare. The patient must be alert and cooperative.
Modalities to Test
| Modality | Pathway | How to Test |
|---|---|---|
| Light touch | Dorsal column | Cotton wool wisp on skin |
| Pain | Spinothalamic tract | Pin prick (disposable pin) |
| Temperature | Spinothalamic tract | Hot/cold tubes |
| Vibration | Dorsal column | 128 Hz tuning fork on bony prominences |
| Proprioception (JPS) | Dorsal column | Hold digit on sides, move up/down |
Key Principle: Pain and temperature travel together (spinothalamic); vibration, proprioception, and fine touch travel together (dorsal columns). This helps localize lesions.
Technique Details
- Vibration: Place 128 Hz tuning fork on bony prominences (great toe, medial malleolus, wrist). Ask patient to say when vibration stops.
- Proprioception (Joint Position Sense): Hold the great toe or finger at the sides (not top/bottom - avoid pressure cues). Move slightly up or down and ask "which direction?"
- Light touch: Use a wisp of cotton along major dermatomes; check for dermatomal loss or distal-to-proximal gradient.
Cortical Sensations (test only if primary sensations normal)
- Stereognosis: Place familiar object in hand (coin, key) - patient identifies with eyes closed
- Graphesthesia: Write a number on patient's palm - patient identifies it
- Two-point discrimination
Key Dermatome Landmarks to Know
| Level | Landmark |
|---|---|
| C5 | Clavicles, deltoid |
| C6 | Thumb |
| C7 | Middle finger |
| C8 | Ring and little fingers |
| T4 | Nipple line |
| T10 | Umbilicus |
| L1 | Groin |
| L4 | Medial aspect of leg/foot |
| L5 | Dorsum of foot, big toe |
| S1 | Sole of foot, lateral foot |
PART 3: REFLEXES
A. Deep Tendon Reflexes (DTRs) - Grading Scale
| Grade | Meaning |
|---|---|
| 0 | Absent |
| 1 | Present but diminished |
| 2 | Normal |
| 3 | Brisker than average (normal) |
| 4 | Pathologically increased, with clonus |
Always test symmetry. Asymmetry is more important than the grade itself.
B. Main Reflexes and Nerve Root Levels
| Reflex | How to Elicit | Root |
|---|---|---|
| Biceps | Tap biceps tendon at elbow | C5 |
| Supinator (Brachioradialis) | Tap lateral radius | C6 |
| Triceps | Tap triceps tendon above elbow | C7 |
| Finger flexors | Tap fingertips - patient's hand in examiner's | C8 |
| Knee (Patellar) | Tap patellar tendon below patella | L3, L4 |
| Ankle (Achilles) | Tap Achilles tendon | S1 |
C. Pathological Reflexes
Babinski Sign (Plantar Response)
- Stroke the lateral sole of foot from heel to ball, then curve medially
- Normal (flexor response): Toes flex (curl downward)
- Abnormal (extensor response = positive Babinski): Great toe extends upward + other toes fan out
- Positive Babinski = UMN (pyramidal tract) lesion in patients over 3 years
- Other terms for the same finding: Upgoing plantar, extensor plantar
Clonus: Rapidly dorsiflex the foot and sustain pressure. Rhythmic beats of dorsiflexion-plantarflexion = UMN lesion.
PART 4: CRANIAL NERVE EXAMINATION
Examine in numerical order (I to XII), but group III, IV, VI together.
| CN | Name | Quick Test |
|---|---|---|
| I | Olfactory | Ask patient (eyes closed) to identify smell (coffee, toothpaste) - each nostril separately |
| II | Optic | Visual acuity (Snellen chart), visual fields by confrontation, fundoscopy |
| III, IV, VI | Oculomotor, Trochlear, Abducens | Pupil size and light reflex, extraocular movements (H-pattern), ptosis |
| V | Trigeminal | Sensation on face (3 divisions: ophthalmic, maxillary, mandibular), corneal reflex, jaw clench |
| VII | Facial | Raise eyebrows (forehead wrinkling), eye closure, smile, cheek puff; note upper vs lower facial weakness |
| VIII | Vestibulocochlear | Whisper test / Rinne & Weber tests for hearing |
| IX, X | Glossopharyngeal, Vagus | Gag reflex, palate elevation ("say aah"), voice quality |
| XI | Accessory | Shoulder shrug (trapezius), head turn against resistance (sternocleidomastoid) |
| XII | Hypoglossal | Tongue protrusion - deviates to side of LMN lesion |
Key CN VII Pointer
- Lower 2/3 face weakness + normal upper face = UMN lesion (contralateral cortex)
- Entire face weakness (upper + lower) = LMN lesion (Bell's palsy, ipsilateral)
Pupil Assessment (CN II + III)
- Miosis (small pupil): Homer's syndrome (loss of sympathetic) or pontine lesion
- Mydriasis (large pupil): CN III compression (parasympathetic runs on outside of nerve - compressed first in herniation)
- RAPD (Relative Afferent Pupillary Defect): Swinging flashlight test - pupil dilates when light swings to affected eye = optic nerve lesion
PART 5: COORDINATION (Cerebellar)
| Test | Technique |
|---|---|
| Finger-nose test | Patient extends arm, touches nose, then touches examiner's moving finger; repeat |
| Heel-knee-shin test | Supine patient slides heel from knee down shin smoothly |
| Rapid alternating movements | Rapid pronation/supination of hands |
| Dysdiadochokinesia | Inability to perform rapid alternating movements = cerebellar lesion |
Romberg's Test: Stand with feet together, eyes open then closed. Falling with eyes closed (positive Romberg) = proprioception/dorsal column defect, NOT cerebellar.
PART 6: CLINICAL CASE HISTORY CHART (5 marks)
Your chart should follow the standard clinical history format:
- Patient bio: Age, sex, occupation, address
- Chief complaint (in patient's own words, with duration)
- History of present illness: Onset, site, duration, character, radiation, aggravating/relieving factors, associated symptoms
- Past history: Similar illness, hospitalizations, surgeries, medications, allergies
- Personal history: Diet, sleep, bowel, bladder, addictions
- Family history: Similar illness in relatives
- Examination findings: General + systemic (CNS) - findings organized under your practical session topic
- Diagnosis / Provisional diagnosis
Common CNS clinical case scenarios to be prepared for:
- Hemiplegia / Stroke: UMN signs on one side, identify which hemisphere is affected
- Parkinsonism: Rigidity, bradykinesia, resting pill-rolling tremor, shuffling gait
- Peripheral neuropathy: Glove-stocking sensory loss, reduced reflexes, distal weakness
- Meningitis: Neck stiffness, Kernig's sign, Brudzinski's sign
- Cerebellar ataxia: Intention tremor, dysdiadochokinesia, nystagmus, ataxic gait
QUICK REVISION CHEAT SHEET
"VITALS" for any CNS exam sequence:
- Visual inspection (wasting, fasciculations, asymmetry)
- Involuntary movements
- Tone
- Active power (MRC grading)
- Lateral comparison reflexes (symmetry)
- Sensation (all modalities)
Key things examiners check:
- Are you comparing both sides?
- Are you explaining what you're doing and why?
- Do you know the difference between UMN and LMN?
- Can you grade muscle power and reflexes correctly?
- Do you know which nerve root = which reflex?
Sources: Harrison's Principles of Internal Medicine 22E, Textbook of Family Medicine 9e, Goldman-Cecil Medicine, Bradley and Daroff's Neurology in Clinical Practice
Good luck tomorrow at 8:30! You've got this. Focus especially on UMN vs LMN differences, MRC grading, and cranial nerve testing - these come up most often in practicals. Let me know if you want me to quiz you or go deeper on any section!
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