Cranial Nerve Examination Flashcards
How do you examine the eye?
sense of smell. Specific testing requires presenting an olfactory stimulus such as tobacco, coffee, or soap. Assessment of CN I is generally omitted unless the patient complains of an olfactory loss.
How do you examine the optic nerve?
Test each eye separately.
a. Visual acuity: test visual acuity, using a hand held card held 14” in front of the patient.
Ask the patient to read the smallest line they can with 100% accuracy. A wall mounted
Snellen chart read at 20 feet is the standard. 20/20 indicates normal vision.
b. Visual fields: test visual fields by confrontation in four quadrants, the right superior, the
right inferior, the left superior, and the left inferior.
Stand in front of the patient a foot apart, nose to nose. Hold fingers out at arm’s length and ask the patient to call out when he/she sees the fingers wiggling.
c. Funduscopic examination: covered under eye exam
d. Pupils: check for constriction to light(CN II afferent)
How do you examine the occulomotor (III), trochlear (IV), and Abducens (VI)?
The mnemonic “SO4, LR6, All the rest 3” helps remind you which CN does what. Superior Oblique: CN 4, Lateral Rectus :CN 6, All the rest of the muscles: CN3)
a. Extra-ocular movements: test the extra-ocular movements in the six cardinal fields of gaze. Ask the patient to keep their head still and follow your finger with their eyes only. Trace the letter H that goes through all the extra-ocular movements.
b. End with bringing your finger toward the patient’s nose-look for papillary constriction (a response called accommodation).
c. Lid strength. Look for ptosis (weakness or drooping of the upper eyelids) CN3.
How do you examine the Trigeminal CN V?
Motor and sensory components. Test with patient’s eyes closed
a. Sensation on the face. Test with the sharp end of a Q-tip.
• Maxillary branch: stroke right and left cheek
• Mandibuar branch: stroke right and left jaw
• Opthalmic branch: stroke right and left forehead and sensory limb of the corneal
reflex: stroke cornea with a wisp of cotton – patient should blink
b. Muscles of mastication: test temporal and masseter muscles while the patient clenches his teeth. Ask patient to move jaw side to side.
How do you examine the Facial VII nerve?
inspect the face and note any asymmetry, tics, or other abnormal movements. Difference between an upper motor neuron and lower motor neuron lesion of the 7th cranial nerve will be taught in Year 2.
a. Muscles of facial expression: ask the patient raise his eyebrows, frown, close his eyes tightly,
show his teeth, smile, puff out his cheeks. Look for symmetry.
b. Taste on anterior 2/3 of tongue – not useful and generally not tested.
c. Motor limb of the corneal reflex – causes blinking when the corneal reflex is checked
How do you examine the Vestibulocochlear (Auditory) VII?
a. Hearing: assess hearing by means of fingers, whispers, or watch tick.
How do you examine the Glossopharyngeal nerve IX?
a. Sensation on soft palate
b. Gag reflex (sensory limb). See below.
How do you examine the Vagus X nerve?
a. Swallowing: observe the elevation of the soft palate when the patient says “ah.” .
b. Gag reflex (motor limb). Test the gag reflex by touching the soft palate or posterior pharynx
with a tongue blade.
c. Note the quality of speech-is there hoarseness?
d. Cardiac function (is there a fixed tachycardia?)
How do you examine the Spinal Accessory XI?
a. Sternocleidomastoid muscles: test by having the patient turn his or her head to each side against resistance of your hand.
b. Trapezius muscles: test by having the patient shrug his or her shoulders upward against your hands.
How do you examine the Hypoglossal XII?
Test for tongue strength by inspecting at rest and when protruded.
