Cranial nerves Flashcards
what is the name of CN XI?
accessory nerve
what is the name of CN VIII?
vestibulococlear
what is the name of CN XII?
hypoglossal
what is the name of CN IX?
glossopharyngeal
which cranial nerves supply only sensory fibres?
olfactory
optic
vestibulococlear
which cranial nerves ONLY provide motor fibres?
occulomotor trochlear abduccent accessory hypoglossal
which cranial nerve provide BOTH sensory and motor fibres?
trigeminal
facial
glossopharyngeal
vagus
where does the olfactory nerve exit the cranium?
through the foraminifera in the cribriform plate of ethmoid bone
what is the clinical significance of the olfactory nerve exiting through the cirbiform plate?
the cirbiform plate is a delicate bone
rapture to this bone could tear the olfactory nerve fibres causing anosmia - loss of smell
which foramen does the optic nerve exit the cranium?
optic canal
what causes papiloedema?
increase in CSF pressure
where does the occulomotor nerve emerge and exit from?
emerges from the mid brain
exits through the superior orbital fissure
what are the components of the occulomotor nerve?
somatic motor- extra ocular muscles & eyelid LPS
visceral motor - parasympathetic supply to the pupil causing constriction and to ciliates muscle causing accommodation of the lens
what is the clinical term for drooping of the eyelid and what does this indicate?
ptosis
indicates there is loss of innervation to the levator palpebrae superioris by the occulomtor nerve
–> damage to the nerve
what position of the eyes indicates there is occulomotor nerve palsy?
the eyes are abducted and looking down
the muscles for abduction (lateral rectus - CN IV) and depression (superior orbital CN VI) aren’t affected
in occulomotor nerve palsy, will there be pupillary reflex?
no
the only time there will be is if the palsy is due to diabetes as this doesn’t cause damage to the parasympathetic fibres
where does the trochlear nerve emerge and exit from?
emerges from the dorsal surface of midbrain
exits through superior orbital fissure
what does the trochlear nerve innervate and what action does this have?
superior oblique
depression of the eye
where does the abducent nerve emerge and exit from?
emerges between pons and medulla and exits via the superior orbital fissure
what does the abducent nerve innervate?
lateral rectus which causes abduction of the eye
where does the trigeminal V1 branch emerge and exit from?
emerged from the pons, travels through the trigeminal ganglion and exits via the superior orbital fissure
the opthalmic branch of trigeminal carries what type of fibres from where?
general sensory fibres from the cornea, forehead, scalp, eyelids, node and mucosa of nasal cavity and sinuses
where does the maxillary branch of trigeminal emerge and exit from?
emerges from the pons
exits through the formate rotundum
what does the maxillary branch of the trigeminal provide sensation to?
face over the maxilla maxillary teeth temeromandibular joint mucosa of nose maxillary sinuses palate
where does V3 emerge and exit from?
emerges from the pons and exits through foramen ovale
what type fo fibres does mandibular branch of trigeminal carry and where?
general sensory to face over the mandible, mandibular teeth, temperomandibular joint, mucosa of mouth and anterior 2/3rds of tongue
somatic motor to muscles of mastication, part of digastric, tensor veil palate and tensor tympani
paralysis of mandibular branch of trigeminal can cause paralysis of reflexes which are?
sneezing reflex
corneal reflex
where does the facial nerve emerge and exit from?
emerges between pons and medulla, exits via internal acoustic meatus, travels through facial canal and exits through stylomastoid foramen
where does facial nerve carry sensory fibres to?
special sensory - taste anterior 2/3rds of tongue & soft palate
general sensory from external acoustic meatus
where does the facial nerve carry motor nerves to?
somatic motor - muscles of facial expression and scalp, stapedius of middle ear
visceral motor - submandibular and sublingual glands, lacrimal glands, glands of nose and palate
palsy of the facial nerve is also called what?
bells palsy
where does the vestibulococclear nerve emerge and exit through?
emerges between pons and medulla and exits via internal acoustic meatus and splits into vestibular and cochlear nerves
where does the glossopharyngeal emerge and exit from?
emerges from the medulla
exits from the jugular foramen
where does the glossopharyngeal supply sensory fibres to?
special sensory - taste to posterior 1/3rd of tongue
general sensory - cutaneous sensations form middle ear and posterior oral cavity
visceral sensory - innervation of parotid gland
where does the glossopharyngeal nerve supply motor nerves?
stylopharyngeus (swallowing)
what can paralysis of the glossopharyngeal nerve result in?
loss of gag reflex and taste from back of tongue
what nerves exit from the jugular foramen?
glossopharyngeal
vagus
accessory
damage to the pharyngeal and laryngeal branches of the vagus nerve causes what effect?
pharyngeal branches = difficulty swallowing
laryngeal branches = difficulty talking
what fibres does the accessory nerve carry and where?
somatic motor to striated muscle of soft palate pharynx larynx sternocleidomastoid & trapezius
what can paralysis in the accessory nerve cause?
weakness in turning head and shrugging shoulders
where does the hypoglossal nerve emerge and exit from?
the medulla and exits through the hypoglossal canal
what fibres does the hypoglossal nerve carry and to where?
somatic motor to muscles of the tongue
what nerve is responsible for movement of the tongue?
hypoglossal
what nerves are responsible for taste of the tongue?
glossopharyngeal posterior and facial anterior (via chord tympani)
what nerves are responsible for swallowing?
glossopharyngeal and hypoglossal
what nerves are responsible for sensation and movement o the face?
sensation - trigeminal
movement - facial
what nerves emerge from the midbrain?
occulomotor and trochlear
what nerve emerge from the pons?
trigeminal nerve
what nerve emerge from the medulla?
glossopharyngeal, vagus, accessory & hypoglossal
what nerves don’t emerge from the brainstem?
optic and olfactory nerves
what nerve emerge from between the pons and medulla?
facial, abducens, vestibulococclear nerves
