Neurological Examination: Cranial Nerves

Preparation

• Mnemonic: WIPE
  • Wash hands, wipe down equipment.
  • Introduce yourself and confirm patient identity.
  • Permission obtained: Explain the exam.
  • Expose patient appropriately (head and neck exposed).
• Equipment Needed:
  • Snellen's visual acuity chart
  • Pen torch
  • Neurotip (sharp object)
  • Tuning fork
  • Glass of water

Cranial Nerves Overview

• Organized structure, numbered I to XII.
• Mnemonics:
  • Names: "O O O To Touch And Feel Very Good Velvet, Such Heaven" (Olfactory to Hypoglossal).
  • Functions: "Some Say Marry Money, But My Brother Says Big Brains Matter More" (Sensory, Motor, Both).

General Inspection

• Look for facial asymmetry, speech disturbances.
• Check for strabismus, abnormal posturing, glasses/hearing aids.

Cranial Nerve I: Olfactory

• Function: Sensory, smell.
• Testing: Informally ask about changes in smell; use smelling bottles.
• Conditions: Anosmia seen in COVID-19, Parkinson's, head trauma.

Cranial Nerve II: Optic

• Function: Sensory, vision.
• Testing: Visual acuity with Snellen's chart, informal reading tests.
• Visual Fields: Compare with examiner's field, quadrant-specific testing.
• Pupil Inspection: Shape and size, reflexes using pen torch.

Reflexes

• Direct Reflex: Pupil constriction to light.
• Consensual Reflex: Contralateral pupil constricts.
• Accommodation Reflex: Pupils constrict when focusing on near object.
• Swinging Light Test: Identifies afferent pupillary defect.

Cranial Nerve III, IV, VI: Oculomotor, Trochlear, Abducens

• Function: Eye movements, motor.
• Testing: "H" shape movement with finger.
• Disorders: Oculomotor palsy (ptosis, pupil dilation), Trochlear palsy (vertical diplopia), Abducens palsy (horizontal diplopia).

Cranial Nerve V: Trigeminal

• Branches: Ophthalmic, maxillary, mandibular (sensory & motor).
• Testing: Touch sensation on face, motor function in mastication.
• Reflexes: Corneal reflex, jaw jerk reflex.

Cranial Nerve VII: Facial

• Function: Motor & sensory (taste).
• Testing: Facial expressions, taste sensation.
• Conditions: Hyperacusis, Bell's palsy.

Cranial Nerve VIII: Vestibulocochlear

• Function: Sensory, hearing and balance.
• Testing: Hearing changes, Rinne's and Weber's tests.

Cranial Nerve IX, X: Glossopharyngeal, Vagus

• Function: Sensory and motor.
• Testing: Voice assessment, swallowing, "ah" test, cough production.

Cranial Nerve XI: Spinal Accessory

• Function: Motor to sternocleidomastoid and trapezius.
• Testing: Head turning and shoulder shrugging against resistance.

Cranial Nerve XII: Hypoglossal

• Function: Motor, tongue muscles.
• Testing: Tongue protrusion, side deviation, cheek pressing.

Conclusion

• Summarize findings to the patient.
• Consider further assessments such as limb neurological exams, imaging, or audiometry.