1. Cranial Nerves
Clinical Assessment
The “FACE” of
Cranial Nerves

2. Cranial Nerves I Olfactory II Optic III Oculomotor IV Trochlear
V Trigeminal
VI Abducens
VII Facial
VIII Acoustic
IX Glossopharyngeal
X Vagus
XI Spinal Accessory
Xii Hypoglossal
Cranial Nerves

3. Cranial Nerves
When assessing the cranial nerves, there are 4 items the examiner must know:
Function
Name & Location of Primary Nuclei
Testing
Signs of Dysfunction

4. Cranial Nerves CN I – Olfactory Nerve Function: special sensory
Name & Location of 1o Nuclei: cribriform plate
Testing:
Use 2-3 vials of familiar odors
Test one nostril at a time with patient’s eyes closed
Use least irritating scent first and allow the patient to rest in between vials
Signs of Dysfunction: anosmia

5. Cranial Nerves CN II – Optic Nerve Function: special sensory
Name & Location of 1o Nuclei: retina
Testing:
Snellen Eye chart
Fundus Exam
Visual fields via confrontation
Pupillary Light reflex
Signs of Dysfunction
Blindness
Loss of pupillary constriction (sensory)

6. Cranial Nerves CN III – Occulomotor Nerve
Function: somatic & visceral motor
Name & Location of 1o Nuclei:
Somatic Motor Nucleus: EOM
Visceral Motor: pupillary constriction & accommodation
Testing:
Six Cardinal Fields of Gaze
Pupillary Light reflex: (motor)
Accommodation
Signs of Dysfunction:
Eye turned down & out w/ ptosis
Mydriasis, Loss of accommodation, Diplopia

7. Cranial Nerves CN IV – Trochlear Nerve Function: somatic motor
Name & Location of 1o Nuclei
Testing:
Six Cardinal Fields of Gaze
Signs of Dysfunction:
Vertical diplopia
Excycodeviation of the eye

8. Cranial Nerves CN V – Trigeminal Nerve Function:
Branchial motor – mastication
General Sensory – sensory to the face
Name & Location of 1o Nuclei –
Motor
Sensory
Mesencephalic Nucleus: proprioception
Pontine Trigeminal Nucleus: touch
Nucleus of Spinal Tract (spinal trigeminal tract): pain & temp

9. Cranial Nerves CN V – Trigeminal Nerve Testing: Signs of Dysfunction:
Sharp & light touch over the three divisions
Corneal Blink Reflex (sensory)
Clinch teeth & Jaw Jerk
Signs of Dysfunction:
Weakness
Hemianesthesia
Absent Corneal Blink Reflex

10. Cranial Nerves CN VI – Abducens Nerve Function: somatic motor
Name & Location of 1o Nuclei
Testing:
Six Cardinal Fields of Gaze
Signs of Dysfunction:
Horizontal diplopia
Medial deviation of the eye

11. Cranial Nerves CN VII – Facial Nerve Function:
Branchial motor – facial muscles
Visceral motor – glandular fcn
General Sensory – skin of the auricle
Special Sensory - taste
Name & Location of 1o Nuclei:
Facial Motor Nucleus
Superior Salivatory Nucleus
Nucleus of Spinal Tract
Nucleus Solitarius

12. Cranial Nerves CN VII – Facial Nerve Testing: Signs of Dysfunction:
Branchial motor component: facial expression
Special Sensory: taste to the anterior 2/3 of tongue
Signs of Dysfunction:
Hemiparesis
Dry eye
Lagophthalmos
Dry mouth
Loss of taste

13. Cranial Nerves CN VIII – Acoustic (Vestibulocochlear) Nerve
Function: special sensory
Name & Location of 1o Nuclei:
Vestibular Nucleus
Dorsal & Ventral Cochlear Nucleus
Testing: hearing tests: Rinne, Weber, Audiology
Signs of Dysfunction:
Vertigo
Nystagmus
Disequilibrium
Sensorineural deafness

14. Cranial Nerves CN IX – Glossopharyngeal Nerve Function:
Branchial Motor – elevation of pharynx during swallowing & speech
Visceral Motor – parotid gland fcn
Visceral Sensory – communication between carotid body & sinus
General Sensory - tongue
Special Sensory - taste

15. Cranial Nerves CN IX – Glossopharyngeal Nerve Testing:
Name & Location of 1o Nuclei:
Nucleus Ambiguous
Inferior Salivatory Nucleus
Nucleus Solitarius
Nucleus of Spinal Tract
Testing:
Branchial Motor: swallowing
General Sensory: gag reflex
Special sensory: taste of posterior 1/3 of tongue

16. TYPICALLY, IX and X are tested together
Cranial Nerves
CN IX – Glossopharyngeal Nerve
Signs of Dysfunction
Dysphagia
Dry mouth
Loss of taste
Loss of gag reflex
TYPICALLY, IX and X are tested together

17. TYPICALLY, IX and X are tested together
Cranial Nerves
CN X – Vagus Nerve
Function:
Branchial Motor – deglutition & phonation
Visceral Motor – smooth muscles of the thoracic & abdominal viscera
Visceral Sensory – thoracic & abdominal viscera
General Sensory – external ear
TYPICALLY, IX and X are tested together

18. Cranial Nerves CN X – Vagus Nerve Testing: Signs of Dysfunction:
Name & Location of 1o Nuclei:
Nucleus Ambiguous
Dorsal Vagal Nucleus
Nucleus Solitarius
Nucleus of Spinal Tract
Testing:
Branchial motor: swallowing, gag reflex, soft palate elevation with uvula remaining while saying “Ah”
Signs of Dysfunction:
Dyspagia
Hoarsness
Uvula deviation

19. Cranial Nerves CN XI – Spinal Accessory Nerve Function: somatic motor
Name & Location of 1o Nuclei
Testing: Resisted shoulder elevation & head rotation
Signs of Dysfunction:
Atrophy & Weakness
Fasciculations
Neck or shoulder deviation

20. CN XII – Hypoglossal Nerve
Cranial Nerves
CN XII – Hypoglossal Nerve
Function: somatic motor
Name & Location of 1o Nuclei
Testing:
Stick out tongue
Press tongue against check while palpating to test muscle strength
Articulation of hard consonants: ‘L’, ‘T’, ‘D’, & ‘N’
Signs of Dysfunction:
Atrophy & Weakness
Deviation
Dysarthria