Cranial Nerves: Clinical applications Flashcards
What is the most probable aetiology of anosmia (loss of smell)
A fractured cribriform plate tearing the olfactory nerve fibres
How does an increase in CSF cause papilloedema
optic nerve carries arteries and veins to the eye, pressure build up due to CSF will increase above venous pressure ( blood isn’t taken away) and will decrease below arterial pressure (blood still going to the eye) this congestion of blood results in overall oedema of the eye
What would occur if there is damage/cut to the right optic nerve
Right sided blindness
What would occur if the optic chiasm was damaged/cut
bitemporal hemianopsia
vision is missing in the outer half of both the right and left visual field
What would occur if the right optic tract was damaged/cut
Left homonymous hemianopsia
loss of half of the field of view on the same side in both eyes
What is the clinical applications if the oculomotor is damaged
drooping of upper eyelid (ptosis)
eyeball abducted and pointing down
(due to SO and LR)
no pupillary reflex
no accommodation of the lens
What is the clinical applications if there is damage to the trochlear CNIV
Diplopia (double vision) when looking down
this is due to the misalignment of the eye so is accompanied with a head tilt to relieve the diplopia giving better alignment
What is the clinical application if there is damage to the abducent CNVI
Poor eye alignment due to medial deviation (cross eyed) causing diplopia (double vision)
What is the clinical applications of damage to trigeminal CNV
Paralysis of muscles of mastication
Loss of corneal or sneezing reflex
Loss of sensation in the face
or
Trigeminal neuralgia (inappropriate senses touch=pain)
What cranial nerve is most frequently injured and why
Facial nerve due to long pathway through the bone
What is the cause of Bell’s palsy
Paralysis of facial nerve
What is the symptoms of Bell’s palsy
Temporary weakness or paralysis of the muscles on one side of the face
Cannot frown,
Close eye lid or bare teeth
What is the clinical applications if vestibulocochlear is damaged
tinnitus (ringing in the ears)
deafness (conductive vs sensorineural)
vertigo (loss of balance)
nystagmus (involuntary rapid eye movements)
What is the clinical application if glossopharyngeal is damaged
Loss of gag reflex and taste from back of tongue
What occurs in jugular foramen syndrome
Injuries to
glossopharyngeal CNIX
Vagus CNX
and Accessory CNXI
