Cranial nerves

Question 1

What is the difference between somatic and visceral motor fibres?

Answer 1

somatic - supply striated muscle

visceral - parasympathetic innervation of smooth muscle and glands

Question 2

What is the difference between general, special and visceral sensory fibres?

Answer 2

general - touch, pain, temperature from skin and mucous membranes
special - taste, hearing, smell, vision, balance
visceral - gut, larynx, heart, not usually conscious

Question 3

path of olfactory nerve

Answer 3

receptors in nasal epithelium - cribriform plate of ethmoid to the olfactory bulb in anterior cranial fossa

Question 4

Fibres of olfactory nerve

Answer 4

special sensory for smell

Question 5

Clinical importance of olfactory nerve

Answer 5

anosmia if it is damaged or if the cribriform plate is fractured and presses on the nerve

Question 6

Fibres of optic nerve

Answer 6

special sensory for vision

Question 7

What fissure do all the nerves which supply muscles of the eye exit?

Answer 7

superior orbital fissure

Question 8

Oculomotor fibres

Answer 8

somatic motor –> EOM

visceral motor –> IOM

Question 9

clinical importance of oculomotor nerve

Answer 9

ptosis, no pupillary reflex, unable to focus close up

Question 10

clinical importance of optic nerve

Answer 10

visual field defects, papilloedema due to CSF pressure increase

Question 11

Trochlear nerve fibres

Answer 11

somatic motor - superior oblique

Question 12

Trochlear nerve clinical importance

Answer 12

diplopia when looking down

Question 13

Abducent fibres and clinical importance

Answer 13

somatic motor for lateral rectus and diplopia

Question 14

What do the different trigeminal branches exit through?

Answer 14

V1 - superior orbital fissure
V2 - foramen rotundum
V3 - foramen ovale

Question 15

What trigeminal branch in addition to general sensory carries somatic motor fibres?

Answer 15

V3

Question 16

Clinical importance of trigeminal nerve

Answer 16

paralysis of muscles of mastication, trigeminal neuralgia, loss of facial sensation, loss of sneeze reflex

Question 17

After the pons what do the trigeminal nerve go through?

Answer 17

trigeminal ganglion

Question 18

Why is it likely the facial nerve can be injured and what is this likely to cause?

Answer 18

long intracranial course

bells palsy

Question 19

What foramen does the vestibulocochlear nerve exit? What does it split into after this?

Answer 19

internal acoustic meatus

vestibular nerve and cochlear nerve

Question 20

Vestibulocochlear nerve fibres and clinical importance

Answer 20

special sensory - hearing and balance

tinnitus, deafness, vertigo, nystagmus

Question 21

Nystagmus

Answer 21

rapid eye movement

Question 22

What foramen does the glossopharyngeal nerve exit?

Answer 22

jugular foramen

Question 23

glossopharyngeal nerve main functions

Answer 23

taste from posterior 1/3 of tongue, parotid glands, stylopharyngeus

Question 24

glossopharyngeal clinical importance

Answer 24

lose gag reflex and taste from back of the tongue

Question 25

Vagus clinical importance

Answer 25

laryngeal branches - difficulty speaking

pharyngeal branch - difficulty swallowing

Question 26

Accessory nerve somatic motor to what 2 muscles?

Answer 26

trapezius and SCM

Question 27

Clinical importance of accessory nerve

Answer 27

difficulty turning head and shoulder

Question 28

Hypoglossal nerve fibres

Answer 28

somatic motor to the tongue muscles

Question 29

Hypoglossal nerve clinical importance

Answer 29

atrophy and paralysis of tongue muscles
deviation of tongue
tonsillectomy - can be damaged