Central nervous system (CNS) examination for medical students

Stethogram

Central Nervous System (CNS) examination guide for MBBS students

Before starting the examination, ensure a thorough CNS history has been taken.

General Physical Examination (GPE)
( Detailed General physical examination)

Patient Position
• Examination performed in a well-lit room.
• Patient adequately exposed.
• Patient examined in a comfortable position.
• Verbal consent obtained.
• Female attendant present (if examining a female patient).

General Appearance
• Comfortable at rest / Ill-looking / Distressed
• Consciousness: Conscious/ Drowsy/ Stuporous/ Comatose
• Cooperation: Cooperative/ Uncooperative
• Orientation:
- Time: Oriented / Disoriented
- Place: Oriented / Disoriented
- Person: Oriented / Disoriented



Higher Mental Functions (HMF)
• Level of Consciousness: Conscious/ Drowsy/ Stuporous/ Comatose

• Cognitive Functions
• Attention and Concentration: Intact / Impaired
• Memory
Immediate memory: Intact / Impaired
Recent memory: Intact / Impaired
Remote memory: Intact / Impaired
• Speech and Language
Normal
Dysarthria
Aphasia: Motor (Broca’s) / Sensory (Wernicke’s)/ Global

• Behaviour and Higher Functions
• Behaviour: Normal / Abnormal
• Judgment: Intact / Impaired
• Abstract thinking: Intact / Impaired
• Insight: Present / Absent



Cranial Nerve Examination

• Olfactory Nerve (CN I)
Sense of smell: Intact / Impaired / Absent (Anosmia)

• Optic Nerve (CN II)
Visual acuity: Normal / Impaired
Visual fields: Full / Defective
Colour Vision (by Ishihara Chart): Normal/ Impaired coloured vision.
Fundus examination: Normal/ Papilledema/ Optic atrophy/ Other: ____

• Oculomotor, Trochlear and Abducens Nerves (CN III, IV, VI)
Pupils: Equal / Unequal
Reactive to light: Yes / No
Reactive to accommodation: Yes / No
Ptosis: Present / Absent
Extraocular movements: Full / Restricted
Nystagmus: Present / Absent
Ophthalmoplegia: Present / Absent

• Trigeminal Nerve (CN V)
Facial sensations: Intact / Impaired
Muscles of mastication:
- Bulk: Normal / Wasted
- Power: Normal / Reduced
Jaw jerk: Present / Absent / Exaggerated

• Facial Nerve (CN VII)
Facial symmetry: Maintained / Asymmetrical
Angle of mouth: Central / Deviated
Forehead wrinkling: Present / Absent
Eye closure: Normal / Weak

• Vestibulocochlear Nerve (CN VIII)
Hearing: Normal / Impaired
Rinne’s test: Positive / Negative
Weber’s test: Central / Lateralized to Right/Left ear

• Glossopharyngeal and Vagus Nerves (CN IX, X)
Palatal movements: Symmetrical / Asymmetrical
Uvula: Central / Deviated
Gag reflex: Present / Absent
Swallowing: Normal / Impaired

• Accessory Nerve (CN XI)
Sternocleidomastoid power: Normal / Reduced
Trapezius power: Normal / Reduced

• Hypoglossal Nerve (CN XII)
Tongue: Central / Deviated
Bulk: Normal / Wasted
Fasciculations: Present / Absent
Movements: Normal / Restricted



Motor System Examination

Inspection
• Muscle wasting: Present / Absent
• Fasciculations: Present / Absent
• Involuntary movements: Present / Absent
• Deformities: Present / Absent
• Abnormal posture: Present / Absent

Muscle Bulk
• Right upper limb: Normal / Reduced
• Left upper limb: Normal / Reduced
• Right lower limb: Normal / Reduced
• Left lower limb: Normal / Reduced
• Symmetry: Symmetrical / Asymmetrical

Muscle Tone
• Right upper limb: Normal / Increased / Decreased
• Left upper limb: Normal / Increased / Decreased
• Right lower limb: Normal / Increased / Decreased
• Left lower limb: Normal / Increased / Decreased
• Type of Increased Tone: Spasticity/ Rigidity

Muscle Power (MRC Grading)
• Muscle Group 
• Shoulder
- Right: ___/5 
- Left: ___/5
• Elbow
- Right: ___/5 
- Left: ___/5
• Wrist
- Right: ___/5 
- Left: ___/5
• Hip
- Right: ___/5 
- Left: ___/5
• Knee
- Right: ___/5 
- Left: ___/5
• Ankle
- Right: ___/5 
- Left: ___/5

Reflex Examination
Superficial Reflexes
• Corneal reflex: Present / Absent
• Abdominal reflex: Present / Absent
• Cremasteric reflex: Present / Absent
• Plantar response: Flexor bilaterally / Extensor (Babinski positive) / Equivocal
• Anal reflex: Present / Absent

Deep Tendon Reflexes (DTRs)
• Biceps
- Right: +
- Left: +
• Triceps
- Right: +
- Left: +
• Supinator
- Right: +
- Left: +
• Knee jerk
- Right: +
- Left: +
• Ankle jerk
- Right: +
- Left: +

• Clonus: Present / Absent
• Pathological reflexes: Present / Absent
• Hoffmann’s sign
• Jaw jerk
• Other: ______________



Sensory System Examination
Primary Sensations
• Fine touch: Intact / Impaired
• Pain: Intact / Impaired
• Temperature: Intact / Impaired
• Vibration sense: Intact / Impaired
• Joint position sense: Intact / Impaired

Pattern of Sensory Loss
- None
- Dermatomal
- Glove-and-stocking
- Hemisensory Sensory level
- Other: ______________

Cortical Sensations
• Stereognosis: Preserved / Impaired
• Graphesthesia: Preserved / Impaired
• Two-point discrimination: Preserved / Impaired
• Sensory extinction: Present / Absent



Cerebellar Examination
• Speech : Normal / Scanning speech

• Eye Movements
Nystagmus: Present / Absent

• Coordination Tests
Finger-nose test: Normal / Abnormal
Heel-shin test: Normal / Abnormal
Rapid alternating movements: Normal / Abnormal

• Cerebellar Signs
Dysmetria: Present / Absent
Dysdiadochokinesia: Present / Absent
Intention tremor: Present / Absent
Rebound phenomenon: Present / Absent



Gait and Station
• Posture: Normal / Abnormal

• Gait: 
- Normal
- Hemiplegic gait
- Cerebellar gait
- High-stepping gait
- Parkinsonian gait
- Spastic gait
- Ataxic gait
- Other: ______________

• Arm swing: Normal / Reduced
• Tandem walking: Normal / Impaired
• Romberg’s test: Negative / Positive



Meningeal Signs
• Neck rigidity: Present / Absent
• Kernig’s sign: Positive / Negative
• Brudzinski’s sign: Positive / Negative



🧠 Central Nervous System Examination
General Physical Examination

The patient is examined in a well-lit room, adequately exposed, in a comfortable position, after taking verbal consent, in the presence of a female attendant (if female patient).

The patient appears comfortable at rest and is conscious, cooperative and well-oriented to time, place and person.

On General Physical Examination, his/her pulse rate is 68 beats/min, regularly regular, of normal volume and character. All peripheral pulses are palpable with no radio-radial delay, radio-femoral delay or vessel wall thickening.

His/her blood pressure is 128/76 mmHg, measured from the right arm in sitting position by the auscultatory method.

His/her respiratory rate is 18/min, thoraco-abdominal/abdomino-thoracic in type, without use of accessory muscles of respiration.

His/her axillary temperature is 98.6°F.

There is no pallor, icterus, cyanosis, clubbing, edema or lymphadenopathy.


Higher Mental Function

On Higher Mental Function examination, attention, memory, speech and language functions are normal, with no evidence of cognitive impairment or behavioural abnormalities.

🔴 Abnormal Clues – Higher Mental Function
  • Altered sensorium and disorientation may suggest diffuse cerebral dysfunction or metabolic encephalopathy
  • Impaired attention and memory deficits may suggest dementia or focal cortical lesions
  • Aphasia and behavioural abnormalities may suggest focal cortical lesions

Cranial Nerves

On cranial nerve examination, the sense of smell is intact. Visual acuity and visual fields are normal. Patient correctly identified all Ishihara chart plates, with no evidenceof Colour vision defect. Pupils are bilaterally equal and reacting to light and accommodation. Extraocular movements are full in all directions of gaze, without ptosis or nystagmus. Facial sensations are intact, and muscles of mastication have normal bulk and power. Facial symmetry is maintained with no deviation of the angle of mouth. Hearing is normal bilaterally. The palate elevates symmetrically, and the uvula is central. Gag reflex is present. Sternocleidomastoid and trapezius muscles have normal power. The tongue is central with normal bulk and movements and no fasciculations.

🔴 Abnormal Clues – Cranial Nerves
  • Anosmia may occur in olfactory nerve lesions and frontal lobe pathology
  • Visual impairment and visual field defects suggest optic nerve or visual pathway lesions
  • Unequal or non-reactive pupils, ptosis, ophthalmoplegia and nystagmus indicate cranial nerve or brainstem involvement
  • Facial asymmetry may suggest facial nerve palsy
  • Hearing impairment may occur in vestibulocochlear nerve lesions
  • Palatal weakness with uvular deviation, absent gag reflex and tongue deviation suggest involvement of the glossopharyngeal, vagus or hypoglossal nerves

Motor System Examination

There is no obvious muscle wasting, fasciculations, involuntary movements or deformities. Muscle bulk is normal and symmetrical in all four limbs. Muscle tone is normal bilaterally. Muscle power is Grade 5/5 in all major muscle groups of both upper and lower limbs.

🔴 Abnormal Clues – Motor System
  • Muscle wasting, fasciculations and hypotonia suggest lower motor neuron lesions, peripheral neuropathies or myopathies
  • Hypertonia and spasticity suggest upper motor neuron lesions
  • Rigidity may occur in extrapyramidal disorders
  • Reduced muscle power may indicate lesions involving the cortex, corticospinal tract, spinal cord, peripheral nerves, neuromuscular junction or muscles

Reflex Examination

Superficial reflexes are present and preserved. Deep tendon reflexes, including biceps, triceps, supinator, knee and ankle jerks, are bilaterally equal and normal (2+). Plantar response is bilaterally flexor, and no pathological reflexes are elicited.

🔴 Abnormal Clues – Reflexes
  • Exaggerated deep tendon reflexes, clonus and an extensor plantar response suggest corticospinal tract involvement and upper motor neuron lesions
  • Diminished or absent reflexes may occur in lower motor neuron lesions, peripheral neuropathies and myopathies
  • Loss of superficial reflexes may indicate segmental spinal cord lesions or upper motor neuron involvement

Sensory System Examination

All primary sensations, including fine touch, pain, temperature, vibration and joint position sense, are intact in all four limbs. Cortical sensations, including stereognosis, graphesthesia, two-point discrimination and sensory extinction, are preserved.

🔴 Abnormal Clues – Sensory System
  • Loss of pain and temperature sensation may occur in peripheral neuropathies and spinothalamic tract lesions
  • Impaired vibration and joint position sense suggest posterior column involvement
  • Cortical sensory deficits indicate parietal lobe dysfunction
  • A sensory level may indicate spinal cord pathology
  • Glove-and-stocking sensory loss suggests peripheral neuropathy

Cerebellar Examination

Speech is normal, and there is no nystagmus. Coordination tests, including finger-nose test, heel-shin test and rapid alternating movements, are normal. There is no dysmetria, dysdiadochokinesia, intention tremor or rebound phenomenon.

🔴 Abnormal Clues – Cerebellar Examination
  • Scanning speech, nystagmus, intention tremor, dysmetria, dysdiadochokinesia and rebound phenomenon suggest cerebellar dysfunction

Gait and Meningeal Signs

The patient's posture and gait are normal, with normal arm swing. Tandem walking is normal, and Romberg's test is negative. There are no signs of meningeal irritation such as neck rigidity, Kernig's sign or Brudzinski's sign.

🔴 Abnormal Clues – Gait and Meningeal Signs
  • A hemiplegic gait suggests upper motor neuron lesions
  • A cerebellar gait indicates cerebellar dysfunction
  • A high-stepping gait suggests peripheral neuropathy
  • A Parkinsonian gait occurs in extrapyramidal disorders
  • A positive Romberg's sign suggests sensory ataxia due to posterior column disease or peripheral neuropathy
  • Neck rigidity, Kernig's sign and Brudzinski's sign suggest meningeal irritation as seen in meningitis or subarachnoid haemorrhage
✅ Impression: Central nervous system examination is within normal limits, with no evidence of focal neurological deficit.
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