Cranial Nerves

1
Cranial Nerves

• Clinical Assessment

The FACE of Cranial Nerves
2
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 patients 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
• 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
• 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
• Name Location of 1o Nuclei
• Nucleus Ambiguous
• Inferior Salivatory Nucleus
• Nucleus Solitarius
• Nucleus of Spinal Tract
• Nucleus Solitarius
• Testing
• Branchial Motor swallowing
• General Sensory gag reflex
• Special sensory taste of posterior 1/3 of tongue

16
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
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
• 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
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