Cranial Nerves - Functions, Symptoms, & Assessment (Milestone #5)

What is the acronym to remember which CNs have Sensory/Motor functions, or have Both?

Some Say Marry Money But My Brother Says Big Brains Matter More

What is the mnemonic to remember the # order of the CNs?

On Old Olympus Towering Tops, A Finn And German Viewed Some Hops

Is the Trigeminal nerve innervation Bilateral or Unilateral?

Bilateral?

Is the Facial nerve innervation Bilateral or Unilateral?

motor: top ½ is bilateral, bottom ½ is unilateral

sensory:

Is the Glossopharyngeal nerve innervation Bilateral or Unilateral?

Bilateral

Is the Vagus nerve innervation Bilateral or Unilateral?

motor: bilateral

sensory:

Is the Hypoglossal nerve innervation Bilateral or Unilateral?

Unilateral

I. Olfactory (sensory or motor)

Sensory

II. Optic (sensory or motor)

Sensory

III. Oculomotor (sensory or motor)

Motor

IV. Trochlear (sensory or motor)

Motor

V. Trigeminal (sensory or motor)

Both

VI. Abducens (sensory or motor)

Motor

VII. Facial (sensory or motor)

Both

VIII. Vestibulocochlear (sensory or motor)

Sensory

IX. Glossopharyngeal (sensory or motor)

Both

X. Vagus(sensory or motor)

Both

XI. Spinal Accessory (sensory or motor)

Motor

XII. Hypoglossal (sensory or motor)

Motor

Olfactory nerve (number)

I

Optic nerve (number)

II

Oculomotor nerve (number)

III

Trochlear nerve (number)

IV

Trigeminal nerve (number)

V

Abducens nerve (number)

VI

Facial nerve (number)

VII

Vestibulocochlear nerve (number)

VIII

Glossopharyngeal nerve (number)

IX

Vagus nerve (number)

X

Spinal Accessory nerve (number)

XI

Hypoglossal nerve (number)

XII

Olfactory function

special sensory: smell

Optic function

special sensory: visual acuity, visual fields

Oculomotor function

sensory: vision

motor: eyelid elevation, most extraocular movements, pupil size/reactions

Trochlear functions

motor: turn eye downward/laterally

Trigeminal function

sensory: facial/mouth sensation, SENSATION for anterior 2/3 of tongue, corneal reflex

motor: chewing, laryngeal muscles, other oral / throat muscles (tensor tympani & tensor velum palatini)

Symptoms of Trigeminal nerve lesion

sensory: decreased touch sensation facial zones, reduced sneeze/corneal reflexes

motor: paralysis of chewing muscles, deviation of jaw toward side of injury

Abducens function

motor: turn eye laterally

Facial nerve function

sensory: TASTE for anterior 2/3 of tongue & soft palate, corneal reflex, stapedius reflex

motor: muscles of facial expression, gland secretion regulation, eyelid & lip closure

Symptoms of Facial nerve lesion

Paralysis/drooping of face muscles, LOSS OF TASTE anterior 2/3 tongue, dysarthria (lip paralysis), excessive eye/palate secretions,

Vestibulocochlear function

sensory: hearing & equilibrium

Glossopharyngeal function

sensory: SENSATION & TASTE for swallowing (posterior 1/3 tongue + pharynx); responsible for GAG REFLEX

motor: gland secretion regulation, stylopharyngeus muscle (assists w/ swallowing)

Symptoms of Glossopharyngeal nerve lesion

Dysphagia, LOSS OF TASTE/SENSATION for posterior 1/3 tongue,*loss of gag reflex, excessive oral secretions, dry mouth)

Vagus function

sensory: SENSATION & TASTE for swallowing (pharynx, larynx, laryngopharynx)

motor: muscles & glands for swallowing (pharynx, larynx, esophagus), phonation (larynx), soft palate elevation

Symptoms of Vagus nerve lesion

Issues with digestion, respiration, heart rate, respiratory rate; reflexes: sneeze, cough, swallow, vomiting

Absent or asymmetrical soft palate elevation (i.e. shown via hypernasality)

Spinal Accessory functions

motor: controls head & shoulders

Symptoms of Spinal Accessory nerve lesion

slouched shoulders, inability to shrug shoulders against resistance, impaired head turn against resistance

Hypoglossal function

motor: tongue movement

Symptoms of Hypoglossal nerve lesion

Dysarthria, dysphagia (oral/oropharyngeal phase)

LMN lesion - wrinkling & flaccidity of tone

Unilateral UMN lesions - not much effect since tongue is bilaterally innervated

Trigeminal physical assessment

motor: open mouth, chew, swallow, chew forward & back, yawn

sensory: test for SENSATION of anterior 2/3 tongue

Facial physical assessment

motor: smile, puff cheeks, raise eyebrows, show teeth, etc.

sensory: check taste anterior 2/3 tongue

glossopharyngeal physical assessment

gag reflex, say Ahhh, check for taste/sensation posterior 1/3 tongue

vagus physical assessment

cough, say Ahhh (check for symmetrical elevation of soft palate/uvula), speak (use voice—phonation)

Spinal Accessory physical assessment

shrug shoulders against resistance, turn head from side to side with resistance

hypoglossal physical assessment

stick out tongue, pull tongue back, check bolus management (oral phase of swallow)