- Position sitting
- Facial asymmetry
- Skin lesions e.g. Sturge-Weber
I – Olfactory Nerve
- Ask patient if any problem with sense of smell
- Use standard set of bottles of non-pungent odours
II – Optic Nerve
- Ask patient to wear spectacles if he normally does
- Visual acuity – one eye at a time with Snellen chart
- Visual fields – one eye at a time by confrontation with finger moving. Map blind spot (red pin).
- Red reflex
- Focus on eye from cornea to fundus – Start at +20 & reduce towards 0. Note cataracts.
- Note colour, vessels, exudates, haemorrhages, retinitis pigmentosa, tears
- Look at macula
- Examine optic disc – atrophy, papilloedema
III – Oculomotor Nerve, IV – Trochlear Nerve, VI – Abducens Nerve
- Note any ptosis, proptosis
- Relative sizes & shape
- Reaction to light
- Relative afferent papillary (IIn) defect (pupil dilates with direct light after consensual constriction)
- Follow pin in “H” pattern to isolate/test individual muscles
- Ask if any double vision
- Summary of actions:
- Medial rectus (MR, III) – adduction (“in”)
- Superior rectus (SR, III) – 1º: elevation, 2º: intorsion, 3º: adduction (“up & in”)
- Inferior rectus (IR, III) – 1º: depression, 2º: extorsion, 3º: adduction (“down & in”)
- Inferior oblique (IO, III) – 1º: extorsion, 2º: elevation, 3º: abduction (“up & out”)
- Superior oblique (SO, IV) – 1º: intorsion, 2º: depression, 3º: abduction (“down & out”)
- Lateral rectus (LR, VI) – abduction (“out”)
- A _potentially confusing aspect is that in order to test muscles individually: SR & IR are tested with the eye _abducted_ _(even though_ _one_ _action of the muscle is_ _adduction) and SO & IO are tested with the eye_ _adducted (even though the_ _one_ _action of the muscle is_ _abduction)!
- CN palsy effects:
- III – Eye is down & out, with dilated pupil unreactive to direct light, ptosis
- IV – Eye elevated (hypertropia). Head tilted to unaffected side.
- VI – Eye may be turned inward (esotropia). Head turns laterally on looking to affected side.
- Conjugate gaze abnormalities – gaze centres in frontal & occipital lobes connect to CN nuclei (III & IV in midbrain, VI in pons). Horiz conjugation relies on co-ordination between VI & III via the medial longitudinal fasciculus & vert by III & IV coord.
- Deviation of both eyes to one side (causes: ipsilat frontal stroke or tumour, contralat brainstem lesion or contralat frontal epileptic stim)
- Supranuclear palsy
- E.g. Steele-Richardson (Vert & then horiz, EPE, neck rigidity, dementia)
- Distinguished from CN palsy by:
- Affects both eyes
- Pupils often fixed & unequal
- Usually no diplopia
- Reflex movements (on neck ext/flexion) are intact
- Supranuclear palsy
V – Trigeminal Nerve (Ophthalmic, maxillary & mandibular divisions)
- Corneal sensation & reflex (afferent component)
- Facial sensation (pin prick & light touch) in each division
- Muscles of mastication (clench teeth, resist mouth closure)
- Jaw jerk (increased in pseudobulbar palsy)
VII – Facial Nerve
- Look up & wrinkle forehead (preserved in UMN lesion)
- Tightly close eyes
- Purse lips and blow out cheeks
- Bare teeth
- Grimace – contracting platysma
- Corneal reflex (efferent component)
VIII – Vestibulocochlear Nerve
Whisper a number in one ear while distracting the other
- Rinne’s test – 256Hz tuning fork on mastoid process then next to EAM. Sound becomes louder unless conductive deafness.
- Weber’s test – 256Hz tuning fork on centre of forehead. If nerve deafness sound heard more on side of normal ear, if conductive deafness then sound heard more on affected side.
- Hallpike test if vertigo
- Examine external auditory canal/tympanic membrane if indicated.
IX – Glossopharyngeal Nerve
- Gag reflex (sensory component)
- Sensation to pharynx
X – Vagal Nerve
- Elevation of soft palate – Say “Ahh”
- Gag reflex (motor component)
XI – Accessory Nerve
- Shrug shoulders against resistance
- Turn head against resistance (right SCM turns head to left & vice versa)
XII – Hypoglossal Nerve
- Examine for wasting or fasciculation of tongue
- Tongue protrusion – deviation is towards the lesion if unilateral LMN
Multiple Cranial Nerve Lesions
- Unilateral V, VII & VIII palsies suggest cerebellopontine angle lesion (tumour)
- Unilateral IX, X & XI palsies suggest a jugular foramen lesion
- Bilateral X, XI, XII suggest bulbar palsy if LMN changes or pseudobulbar palsy if UMN signs.
- Weakness of eye & facial muscles esp with repetition suggests myasthenia.
Summary of Examination of Eyes