Cranial Nerves Clinical Assessment The “FACE” of Cranial Nerves

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

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

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

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)

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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