Cranial nerves Flashcards
What is the first cranial nerve?
Olfactory
Which nerve is the the olfactory?
1st
Where does the olfactory pass throught he skull?
The cribriform plate
Where does the olfactory nerve go?
Directly to cortex not through thalamus only smell does this
How much of the smell goes to opposite side?
85% stays same side 15% crosses over
What can affect the olfactory nerve?
olfactory groove meningioma, parkinson’s epilepsy trauma in car crashes
Where does olfactory nerve pass?
To he entorhinal cortex in the medial temporal lobe
What type of fibres does the olfactory nerve carry?
sensory only (special)
What does the optic nerve carry?
sensory only (special)
Which nerve is the 2nd cranial nerve?
Optic nerve
Where does the optic nerve leave/enter the skll?
The optic canal
What happens to the fibres of the optic nerve(general overview)?
Passes to chiasm and fibres cross over, pass to the lateral geniculate nucleus in thalamus thenthrough pariaetal or temporal lobes to the visual cortex
Explain the pathway of nasal fibres of the optic nerve?
They show the temporal field they cross over to the other sied and go round contralateral radiation
What happens to inerior fibres of eye?
They have superior visual field and theygo through the temoiral lobe
What is the erdinger-westphal mucluse?
It is involved in pupilary reflex and occulomotor nerve recieves feedback from the optic nerve
What is the 3rd creanial nerve?
The occulomotor nerve
What is the oculomotor nerve?
the 3rd nerve
What does a 3rd nerve palsy cause?
down and out from superior oblique and lateral rectus
How can the optic nerve be tested?
Visual fields, pupil reflex(but relies on occulomotor) visual acuity, fundoscopy
What is the shape of the optic disk?
A cup shape so in normal the light bit and moving can tell if it is normal or swollen
What can affect the pupilary reflex?
Siphillis will accomodate but slow to react to light
horner’s syndrome damage to sympathetic so droopy eyelid and small pupil
Holmes-adi pupul difference in size
How does optic nerve lesion affect the pupil?
Won’t react to light and will be dialated more than normal
What type of signal doe occulomotor, trochlear and abducens?
all skeletal motor but oculomotor does parasympathetic
What is the action of superior oblique?
It intorsion, and abduction and declination
Whre does occulomotor exit the brainstem?
The pontine sulcus at the front
Where does the trochelar nerve exit the brainstem?
at the back of the pons
What passes through the superior orbital fissue?
The 3rd 4th and opthalmic division of trieminal
Where is the sixth cranial nerve leave the brain?
Bulbopontine sulcus
What is sign of 4th nerve palsy?
trochlear double vision looking down
What does the parasympathetic component of 3rd nerve do?
the short ciluarry muscles to contrace the lens and sphincter muscels to constricp pupil
What is involved in the trigeminal nerve?
Sensatin to the face 3 divisions opthalmic top of head sclera of eye and top of nose, maxilliary upper lip, and mandubilar division along jaw
It does muscles of mastication.
The tongue normal sensation to anterior 2/3s
What fibres are involved in the trigeminal nerve?
Somatic sensation to anteror 2/3 of tongue and face also the muscles of mastication
