Cranial Nerves

Question 1

Testing Cranial Nerve I

Answer 1

Nerve: Olfactory

Type: Sensory

Testing
-eyes closed*
-occlude 1 nostril at a time, smell familiar substance

Findings
-note any asymmetry
-anosmia - decrease or loss of smell (smoking, allergic rhinitis, cocaine use)

Considerations
-smell decreases bilaterally with age
-can’t test if occluded e.g. sinusitis

Question 2

Testing Cranial Nerve II

Answer 2

Nerve: Optic

Type: Sensory

Testing
-Visual acuity - Snellen
-Visual fields - confrontation (side)
-Ophthalmoscope - look at fundus, optic disc

Findings
-ABNORMAL - blurry optic disc (signifies increased intracranial pressure - emergency!)
-deficits in visual field

Question 3

Testing Cranial Nerves III, IV, VI

Answer 3

Nerve III: Oculomotor (pupil)
Type: Motor

Nerve IV: Trochlear (superior oblique)
Type: Motor

Nerve VI: Abducens (lateral rectus)
Type: Motor

Testing
-Pupil constriction, accommodation
-Cardinal gazes

Findings
Normal: PERRLA

Abnormal
-Unilateral dilation
-Non reactivity
-Deviation in gaze
-Nystagmus - rapid movement
-Ptosis - drooping

Question 4

Testing Cranial Nerves V

Answer 4

Nerve: Trigeminal

Type: Both

Testing - Motor
-muscle of mastication
-palpate TMJ as patient clenches teeth

Findings - Abnormal
-Decreased strength on one or both
sides
-Asymmetry in jaw movement
-Pain with clenching of teeth

Testing - Sensory
-patient’s eye closed*
- brush cotton wisp on forehead, cheeks, chin
-patient says where and when the sensation is felt
-corneal reflex - not done routinely

Findings - Abnormal
-decreased or unequal sensation

Question 5

Testing Cranial Nerve VII

Answer 5

*If sensation is not normal on the face

Nerve: Facial

Type: Both

Testing - Motor
-smile, frown, close eyes tightly, lift eyebrows, puff cheeks, show teeth

Findings
-Mobility and symmetry
Abnormal/critical:
-Muscle weakness
-Flattening of the nasolabial fold
-Drooping of one side of the face
-Lower eyelid sagging
-Escape of air from only one side of the check that is pressed in

Testing - Sensory
-cotton applicators soaked in sugar, salt, or lemon juice to tongue
-patient identifies the taste

Question 6

Testing Cranial Nerve VIII

Answer 6

Nerve: Vestibulocochlear

Type: sensory

Testing:
Cochlear division (hearing)
-Whisper test

Vestibular division (balance)
-Weber test - tuning fork on middle of head→ not precise or reliable data
-Rinne Test - bone vs air conduction, don’t do routinely

Findings:
-note symmetry

Question 7

Testing Cranial Nerves IX and X

Answer 7

Nerve IX: Glossopharyngeal (saliva)
Type: Both

Nerve X: Vagus (swallowing)
Type: Both

Testing - Motor
-depress tongue and have patient say “ah”
-gag reflex - maybe not

Findings
-uvula and soft palate should rise in the midline, and the tonsillar pillars should move medially
-note asymmetry, lack of movement

Testing - Sensory
-mediate taste on the posterior one-third of the tongue
-too difficult to test

Question 8

Testing Cranial Nerve XI

Answer 8

Nerve: Spinal Accessory

Type: Motor

Testing:
-resistance against chin and shoulders

Findings:
-muscle weakness, paralysis

Question 9

Testing Cranial Nerve XII

Answer 9

Nerve: Hypoglossal

Type: Motor

Testing:
-Inspect the tongue
-Patient says, “light, bright, dynamite”

Findings:
Normal:
-No tremors
-Should come out straight, midline
-Clear speech

Abnormal:
-Slurring