Cranial Nerves Flashcards
What is different about where the first two cranial nerves originate?
They are extensions of the forebrain whereas other cranial nerves originate from the brain stem
Which 4 cranial nerves originate from the pons?
CN 5-8
Which cranial nerves originate from the midbrain?
Cranial nerves 3 and 4
What special sense does CN 1 provide?
Special sense of smell
What special sense does CN 2 provide?
Special sense of vision
Why is it that in damage to the oculomotor nerve by compression the pupil is blown?
Parasympathetic fibres are found peripherally on nerve so will be affected by compression
What part of brain is likely to compress the oculomotor nerve with increased intracranial pressure?
The uncus of the temporal lobe as it extends over the free edge of the tentorial notch
What happens to cause a false localising sign in CN 6?
Intracranial pressure pushes brain stem down slightly which puts tension and stretches CN 6
What is ptosis?
Drooping eyelid
What is dipoplia?
Double vision
Which muscles of the eye do the motor fibres of CN 3 supply?
4 out of 6 of the extra ocular muscles,
Levator palpebrae superioris
What muscle of the eye do the parasympathetic fibres of CN 3 supply?
Sphincter pupillae
Which cranial nerves originate from the medulla?
Cranial nerves 9-12
Which of the cranial nerves supplies the SCM and trapezius muscles?
The accessory nerve (CN11)
Which nerves supply the taste and sensory functions of the tongue
Posterior third is glossopharyngeal for both.
Anterior two thirds: taste is facial nerve, sensory is trigeminal
Where does the opthalmic division of the trigeminal nerve exit the base of the skull?
The superior orbital fissure
Where does the maxillary branch of the trigeminal nerve exits the base of the skull?
Foramen rotundum
Where does the mandibular branch of the trigeminal nerve exit the base of the skull?
Foramen ovale
What is the hutchinson’s sign?
When shingles affecting opthalmic division involves tip of nose showing nasocilliary nerve involvement
Which of the trigeminal nerve divisions travel through the cavernous sinus?
Opthalmic and maxillary
What are the ranches of the opthalmic division of the trigeminal nerve (CN5)?
Supraorbital, supratrochlear, lacrimal, frontal and nasociliary nerves
Which nerve branching off of the mandibukar branch of trigeminal nerve supplies the sensory for anterior two thirds of tongue?
Lingual nerve
Through which bone does the olfactory nerve leave the anterior cranial fossa to enter the nasal cavity?
The cribiform foramina in the cribiform plate of the ethmoid bone
Through where does the optic nerve and opthalmic artery enter the orbit?
Optic canal
