4.1 Cranial Nerves Flashcards
What is the name of CN I?
Olfactory nerve
What is the function of the Olfactory nerve?
Provide a sense of smell
Where does CN I originate?
Olfactory mucosa –> cribriform plate –> olfactory bulb
What is anosmia?
Lack of smell
What can cause anosmia?
Trauma, meningtitis
What is the name of CN II?
Optic nerve
Describe the pathway of CNII
Retina –> Optic tract –> Optic canal –> Primary visual cortex
What is the name of CN III?
Occulomotor
Where does CN III originate?
Oculomotor nucleus
Describe the pathway of CN III?
Superior orbital fissure and splits into superior and inferior oculomotor nerve.
What is the function of the optic nerve?
Sight
What is the function of CN III?
Movement of 4/6 of the extraocular eye muscles and levator palpebrae superioris
How will a CN III nerve palsy present?
Down and out pupil Enlarged pupil (mydriasis)
What is the name of CN IV?
Trochlear
What is the function of the trochlear nerve?
Moves eye down and in
Describe the pathway of CN IV
Trochlear nucleus –> cavernous sinus –> eye muscles
How may an infection on CN IV present?
Difficulty walking down the stairs
Why is CN IV susceptible to infections?
Longest and runs through cavernous sinus
What is the name of CN V?
Trigeminal
Where does the Trigeminal nerve originate?
Trigeminal sensory nucleus complex in the Pons
Name the 3 branches of CN V
Opthalmic (V1)
Maxillary (V2)
Mandibular (V3)
What is the function of the trigeminal nerve?
General sensation to the face and innervation of the muscles of mastication
What is trigeminal neuralgia?
Overactive sensory portion of CN V causes burning pain
What is the name of CN VI?
Abducens Nerve
Where does the abducens nerve originate?
Abducens nuclei in the pons
What is the function of the abducens nerve?
Lateral eye movements
What is the name of CN VII?
Facial nerve
Name the motor branches of the facial nerve
Temporal Zygomatic Buccal Mandibular Cervical
What do the sensory fibres of the facial nerve innervate?
Taste receptors of anterior 2/3rds of the tongue
What do the parasympathetic fibres of the facial nerve innervate?
Salivary and lacrimal glands
Which foramina do all branches of the facial nerve pass through?
Internal acoustic meatus
What is Bell’s Palsy?
Idiopathic unilateral facial paralysis due to inflammation at the stylomastoid foramen
What is the name of CN VIII?
Vestibulocochlear
Describe the pathway of CN VIII
Cerebellopontine angle in the Pons, then splits into vestibular nerve and cochlear nerve.
What is the function of the vestibular nerve?
Control of balance
What is the function of the cochlear nerve?
Hearing
What test is done to check for sensory and conductive hearing loss?
Rinne and Webbers test
What is the name of CN IX?
Glossopharyngeal
What does the glossopharyngeal nerve give motor innervation to?
Stylopharyngeus
What does the glossopharyngeal nerve give sensory innervation to?
Oropharynx
Posterior 1/3rd tongue
Carotid sinus
What does the glossopharyngeal nerve give parasympathetic innervation to?
Parotid gland
Which pathway is CN IX in the gag reflex?
Afferent pathway
What is the name of CN X?
Vagus nerve
What does the vagus nerve give motor innervation to?
Muscles of the pharynx and larynx
What does the vagus nerve give sensory innervation to?
Laryngopharynx, ear
What does the vagus nerve give parasympathetic innervation to?
Heart, lungs, GI tract
Which pathway is CN X in the gag reflex?
Efferent pathway
What is the name of CN XI?
Accessory nerve
Which artery does CN XI follow?
Internal carotid artery
What does the Accessory nerve innervate?
SCM and trapezius
What is the name of CN XII?
Hypoglossal
What does the hypoglossal nerve innervate?
Intrinsic and extinsic muscles of the tongue