Cranial Nerves Flashcards
what is the name of the first cranial nerve
olfactory nerve
describe the route of the olfactory nerve
if exits the forebrain and runs through the cribriform foramen to form the olfactory bulbs
what is the function(s) of the olfactory nerve
sense smell
how can you test the olfactory nerve
using smelling salts on one nostril at a time
what can cause damage to the olfactory nerve
head damage or tumour of the frontal lobes
what is the name of the second cranial nerve
optic nerve
describe the route of the 2nd cranial nerve
exits the forebrain and goes through the orbital canal to the orbit of the eye to supply the retina
what is the function of the 2nd cranial nerve
sense sight
what is the optic chiasma
where nerve fibres from the optic nerves cross over
what does impingement on the optic chiasma by a pituitary tumour cause
bitemporal hemianopia
how do you test the 2nd cranial nerve
visual tests
pupil reflexes
looking at optic disc for papillodema
what is papillodema
where the optic disc is swollen and blurry
what causes papillodema
raised intracranial pressure
what is the 3rd cranial nerve
oculomotor nerve
what is the route of the oculomotor nerve
arises from the midbrain and goes through the cavernous sinus and through the superior orbital fissure
what is the function of the 3rd cranial nerve
supplies most of the muscles controlling eye movements
autonomic fibres control pupil constriction and lens thickness
controls muscle to keep eyelids open
how do you test the 3rd cranial nerve
look at eye movements, pupil light reflexes and drooping of eye lids
what is the first sign of compression of the 3rd cranial nerve and why does this occur first
the parasympathetic fibres are located on the outside of the nerve, so these would be compressed first causing pupil dilation
what causes compression of the 3rd cranial nerve
raised intracranial pressure forcing the uncut past the tentorium cerebelli to push on the nerve
what is the 4th cranial nerve
the trochlear nerve
what is the route of the trochlea nerve
exits the midbrain and goes through the cavernous sinus and the superior orbital fissure
what is the function of the 4th cranial nerve
supplies the muscle which moves the eye up
what is the test for the 4th cranial nerve
eye movements
what signs/symptoms may result from damage to the 4th cranial nerve
diplopia
what is the 5th cranial nerve
trigeminal nerve
what are the 3 main branches of the trigeminal nerve
ophthalmic, maxillary and mandibular
describe the route of the ophthalmic nerve branch
comes from the trigeminal at pons and goes through the cavernous sinus and the superior orbital fissure
describe the route of the maxillary nerve branch
comes from the trigeminal at pons, goes through the cavernous sinus and the foramen rotundum