Cranial Nerve 2 Flashcards
What are 3 subdivisions of trigeminal nerve?
- Ophthalmic: V1
- Maxillary: V2
- Mandibular: V3
What is function of opthalamic nerve?
sensory information from:
- scalp
- forehead
- nose
- upper eyelid
- conjunctiva
- cornea of the eye
What is function of maxillary nerve?
- sensory information from
1. lower eyelid
2. cheek
3. nares
4. upper lip
5. upper teeth
6. gums
What is sensory function of mandibular nerve?
- sensory information from
1. chin
2. jaw
3. lower lip
4. mouth
5. lower teeth
6. gums.
What is the motor function of the mandibular nerve?
- to the
1. muscles of mastication (masseter, temporal muscle and the medial/lateral pterygoids)
2. tensor tympani
3. tensor veli palatini
4. mylohyoid
5. digastric
What muscle does raised eyebrows test?
assesses frontalis
What muscle does closed eyes assess?
orbicular oculi
What muscle does blown out cheeks assess?
orbicularis oris
What muscle does smiling assess?
levator anguli oris and zygomaticus major
What muscle does pursed lips assess?
orbicularis oris and buccinator
What can facial nerve palsy present with?
unilateral weakness of the muscles of facial expression
What does facial nerve palsy caused by LMN lesion present with?
weakness of all ipsilateral muscles of facial expression, due to the loss of innervation to all muscles on the affected side
What is most common cause of lower motor neuron facial palsy?
Bell’s palsy
How does facial nerve palsy caused by UMN lesion?
unilateral facial muscle weakness
What muscle is spared in facial palsy caused by UMN lesion and why?
upper facial muscles partially spared because of bilateral cortical representation (resulting in forehead/frontalis function being somewhat maintained)
What is most common cause of UMN lesion facial palsy?
stroke
What vibration is tuning fork in Rinne’s?
512Hz
What is Rinne’s positive?
can hear the sound suggests air conduction is better than bone conduction, which is what would be expected in a healthy individual
What is normal result of Rinne’s?
air conduction > bone conduction (Rinne’s positive)
What is sensorineural deafness with Rinne’s test?
air conduction > bone conduction (Rinne’s positive) – due to both air and bone conduction being reduced equally
What is conductive deafness in Rinne’s?
bone conduction > air conduction (Rinne’s negative)
What is normal result with Weber’s?
sound is heard equally in both ears
What is the sensorineural deafness in Weber’s?
sound is heard louder on the side of the intact ear
What is conductive deafness in Weber’s?
sound is heard louder on the side of the affected ear
What is conductive hearing loss?
sound is unable to effectively transfer at any point between the outer ear, external auditory canal, tympanic membrane and middle ear (ossicles)
What are causes of conductive hearing loss?
- excessive ear wax
- otitis externa
- otitis media
- perforated tympanic membrane
- otosclerosis
What is sensorineural hearing loss?
due to dysfunction of the cochlea and/or vestibulocochlear nerve
What are the causes of sensorineural hearing loss?
- increasing age (presbycusis)
- excessive noise exposure
- genetic mutations
- viral infections (e.g. cytomegalovirus)
- ototoxic agents (e.g. gentamicin)
What is the motor function of the glossopharyngeal nerve?
stylopharyngeus muscle which elevates the pharynx during swallowing and speech
What is the sensory function of glossopharyngeal nerve?
transmits sensory information that conveys taste from the posterior third of the tongue
What do the visceral sensory fibres of glossopharyngeal nerve do?
mediate the afferent limb of the gag reflex
What is the motor function of the vagus nerve?
to several muscles of the mouth which are involved in the production of speech and the efferent limb of the gag reflex
What is the motor function of accessory nerve?
sternocleidomastoid and trapezius muscles
What is the motor function of the hyopglossal nerve?
to the extrinsic muscles of the tongue (except for palatoglossus which is innervated by the vagus nerve)
What does hypoglossal nerve palsy look like?
- atrophy of the ipsilateral tongue
2. deviation of the tongue when protruded towards the side of the lesion
What causes hypoglossal nerve palsy?
due to the overaction of the functioning genioglossus muscle on the unaffected side of the tongue
