Nervous | Cranial Nerves Examination

Nervous: Cranial Nerves Exam
  1. Setup
  2. I: Olfactory
  3. II: Optic
  4. III-IV-VI: extraoculars
  5. V: Trigeminal
  6. VII: Facial
  7. VIII: Vestibulocochlear
  8. IX-X: GlossopharyngealVagus
  9. XI: Accessory
  10. XII: Hypoglossal
Setup
  • Patient sitting over edge of bed.
CN I: Olfactory
  • Usually not tested.
  • Rashdeformity of nose.
  • Test each nostril with essence bottles of coffeevanillapeppermint.
CN II: Optic
  • With patient wearing glassestest each eye separately on eye chart/ cardusing an eye cover.
  • Examine visual fields by confrontation by wiggling fingers 1 foot frompt's earsasking which they see move.
    • Keep examiner's head level with patient's head.
  • If poor visual acuitymap fields using fingers and a quadrant-coveringcard.
  • Look into fundi.
  • For more detailSee Eye Exam.
CN IIIIVVI: OculomotorTrochlearAbducens
  • Look at pupils: shaperelative sizeptosis.
  • Shine light in from the side to gauge pupil's light reaction.
    • Assess both direct and consensual responses.
    • Assess afferent pupillary defect by moving light in arc from pupil topupil. unne). Optionally: as do arc testhave pt place a flat handextending vertically from his facebetween his eyesto act as a blinder solight can only go into one eye at a time.
  • "Follow finger with eyes without moving head": test the 6cardinal points in an H pattern.
    • Look for failure of movementnystagmus [pause to check it during upward/lateral gaze].
  • Convergence by moving finger towards bridge of pt's nose.
  • Test accommodation by pt looking into distancethen a hat pin 30cm fromnose.
  • If MG suspected: pt. gazes upward at Dr's finger to show worsening ptosis.
CN V: Trigeminal
  • Corneal reflex: patient looks up and away.
    • Touch cotton wool to other side.
    • Look for blink in both eyesask if can sense it.
    • Repeat other side [tests V sensoryVII motor].
  • Facial sensation: sterile sharp itemon foreheadcheekjaw.
    • Repeat with dull object. Ask to report sharp or dull.
    • If abnormalthen temperature (heated/ water-cooled tuning fork)lighttouch (cotton).
  • Motor: pt opens mouthclenches teeth (pterygoids).
    • Palpate temporalmasseter muscles as they clench.
  • Test jaw jerk (pseudobulbar palsy).
CN VII: Facial
  • Inspect facial droop or asymmetry.
  • Facial expression muscles: pt looks up and wrinkles forehead.
    • Examine wrinkling loss.
    • Feel muscle strength by pushing down on each side [UMNL preserved becauseof bilateral innervation].
  • Pt shuts eyes tightly: compare each side.
  • Pt grins: compare nasolabial grooves.
  • Also: frownshow teethpuff out cheeks.
  • Corneal reflex already done. See CN V.
CN VIII: Vestibulocochlear (HearingVestibularrarely)
  • Dr's hands arms length by each ear of pt.
    • Rub one hand's fingers with noise on one sideother hand noiselessly.
    • Ask pt. which ear they hear you rubbing.
    • Repeat with louder intensitywatching for abnormality.
  • Weber's test: Lateralization
    • 512/ 1024 Hz [256 if deaf] vibrating fork on top of patients head/forehead.
    • "Where do you hear sound coming from?"
    • Normal reply is midline.
  • Rinne's test: Air vs. Bone Conduction
    • 512/ 1024 Hz [256 if deaf] vibrating fork on mastoid behind ear. Ask whenstop hearing it.
    • When stop hearing itmove to the patients ear so can hear it.
    • Normal: air conduction [ear] better than bone conduction [mastoid].
  • If indicatedlook at external auditory canalseardrums.
CN IXX: GlossopharyngealVagus
  • Voice: hoarse or nasal.
  • Pt. swallowscoughs (bovine cough: recurrent laryngeal).
  • Examine palate for uvular displacement. (unilateral lesion: uvula drawn to normalside).
  • Pt says "Ah": symmetrical soft palate movement.
  • Gag reflex [sensory IXmotor X]:
    • Stimulate back of throat each side.
    • Normal to gag each time.
CN XI: Accessory
  • From behindexamine for trapezius atrophyasymmetry.
  • Pt. shrugs shoulders (trapezius).
  • Pt. turns head against resistance: watchpalpate SCM on opposite side.
CN XII: Hypoglossal
  • Listen to articulation.
  • Inspect tongue in mouth for wastingfasciculations.
  • Protrude tongue: unilateral deviates to affected side.

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