April 11, 2024

Cranial nerve examination is a part of neurological examinations where 12 cranial nerves are examined in sequences.

Cranial nerve in sequences
Cranial nerve

12 pairs of Cranial Nerves

OOO Timro Tyo Aakha Fikka Vo Gajal Varera Aau Hai

Olfactory Nerve (I)

First, take consent in all examinations:

Check Nasal patency=>Close eyes =>Place strong stimulus

Stimulus is:

  • Soap
  • Lemon
  • Garlic
  • Cardamom
(soap, lemon, garlic, cardamom) are stimulants used in olfactory examinations

Check Bilaterally and compare

Optic Nerve (II)

Optic nerve examinations are discussed in the following four headings:

  1. Visual Acquity
  2. Color Vision
  3. Field of vision
  4. Pupillary reflexes

Visual acuity

Check in Snellen’s chart

Snellen's chart

Visual Acquity= Distance/Smallest letter distance

Distance is generally kept at 6 meter

Check is done by both Right eye and Left eye

After 1/60 visual acquity==>Do Finger counting test ==>Hand movement test ==> Perception of light

Pocket carrying: E chart (Tumbling E-chart)

E-Chart

Field of Vision

Check-in 1-meter distance

Stretch hand: from left, right, above, and down

Color vision

Check-in Ishihara chart

Pupillary Reflexes

In Dark Room=>Look for the response of pupil=> Normal is Constriction

Look for consensual reflexes also

Accommodation reflex: distance vision to orbit

Oculomotor, Trochlear and Abducens (III, IV, VI)

Inspection:

Any palpebral fissure, look for Ptosis

Fix the head and Check the movement of eyes in all directions

Superior oblique muscle is supplied by the Trochlear nerve (IV), the Lateral rectus is supplied by Abducens (VI), and the rest are supplied by the Oculomotor

SO4+LR6, Rest 3

Trigeminal Nerve (V)

Sensory

Test all divisions of the trigeminal nerve i.e.

  • Ophthalmic division
  • Maxillary division
  • Mandibular division

Motor

Examine muscle of mastication for any motor deficits.

  1. Massector
  2. Pterygoid
  3. Buccal

Facial Nerve (VII)

Sensory evaluation:

  • Wipe the tongue first and then evaluate every portion of the tongue
  • Sugar(sugar), Bitter(quinine), Salt(table salt) and Sour(lemon)

Schermer’s test

See for Bells phenomena

Look for lagopthalmus

To check Facial muscles: Ask the patient to whistle

UMN vs LMN

Vestibulocochlear (VIII)

Tuning fork
Tuning fork

Rinne’s test

Check for Air conduction vs Bone conduction (By 128 Hz tuning fork)

Normal: Air conduction is better than bone conduction

Weber test:

The sound heard equally on both sides

Vestibular test

See for nystagmus

Calorie test

Glossopharyngeal Nerve (IX)

Sensory

Posterior 1/3rd sensory testing

Motor:

  1. Palatal reflex
  2. Gag reflex: Contraction of Post-pharyngeal (Normal)

Vagus Nerve is also intact if the gag reflex is present and normal

Spinal accessory nerve (XI)

See prominence of SCM muscle and Trapezius muscle

Check motor/power of muscle

Hypoglossal Nerve (XII)

Inspection:

See deviation of tongue, atrophy, fasciculation

Palpation:

Provide pressure by tongue on the mouth.

See also: Sensory Examination

See also: Motor Examination

See also: Neurological Examination