UNIT 3: cranial nerves

Question 1

what is the mnemonic to remember the names of the cranial nerves?

Answer 1

on old olympic’s towering top a finn and german viewed some hops

Question 2

what are the names of the 12 cranial nerves?

Answer 2

olfactory, optic, oculomotor, trochlear, trigeminal, abducens, facial, auditory (vestibulocochlear), glossopharyngeal, vagus, spinal accessory, hypoglossal

Question 3

where do the first two cranial nerves arise from?
what else sets them apart from the others?
what foramen do they pass through?

Answer 3

arise from forebrain
they are brain tracts not nerves (axons cannot degenerate)
I - foramina of the cribriform plate
II - optic canal

Question 4

which of the cranial nerves supply the eye muscles? - which foramen do they pass through?

Answer 4

III - oculomotor
IV- trochlear
VI - abducens
- pass through superior orbital fissure

Question 5

where does cranial nerve III emerge from? give its function

Answer 5

oculomotor: emerges immediately from pons
- supplies superior/ medial/ inferior rectus/ inferior oblique
- focus of lens
- papillary constriction

Question 6

where does cranial nerve IV emerge from? give its function

Answer 6

trochlear - supplies superior oblique

dorsal side of pons

Question 7

where does cranial nerve VI emerge from? give its function

Answer 7

abducens - supplies lateral rectus

posterior side of pons

Question 8

which nerves supply the face?

Answer 8

V - trigeminal
VII - facial
VIII - auditory

Question 9

describe the sensory and motor functions of the trigeminal nerve

Answer 9

sensory: face, mouth, nasal cavity, cornea
motor: muscles of mastication

Question 10

what is the largest division of the trigeminal nerve and describe its sub parts?
- what foramina do its subdivisions pass through?

Answer 10

ophthalmic:

• frontal (supratrochlear/ supraorbital) = skin of upper eyelid/ frontal sinus/ forehead
• nasociliary = skin of nasal tip
• lachrymal

ophthalmic - superior orbital fissure
maxillary - foramen rotundum
mandibular - foramen ovale

Question 11

how can levels of consciousness be measured?

Answer 11

glasgow coma scale - press finger against supraorbital notch for pain and manual stimulation of nerve

Question 12

where does the infraorbital nerve pass through and what is its function?

Answer 12

infraorbital foramen

- innervates upper lip, lower eyelid and nasal vestibule

Question 13

where does cranial nerve VII emerge from?

what foramen does it pass through? give its function

Answer 13

emerges posterior to pons
passes through the internal acoustic meatus
sensory: taste sensation anterior 2/3 of tongue, salivary glands. lachrymal glands/ mucosal glands - nasal secretion (parasympathetic)
motor: muscles of facial expression

Question 14

where does cranial nerve VIII emerge from?
what foramen does it pass through?
give its function

Answer 14

emerges posterior to pons/ lateral to facial nerve
internal acoustic meatus
hearing and balance

Question 15

which nerves emerge from medulla?

which foramina do they pass through

Answer 15

IX - glossopharyngeal  (dorsal to olive)
X - vagus (dorsal to olive)
XI - spinal accessory (dorsal to olive)
- pass through the jugular foramen
XII - hypoglossal (ventral to olive)
- pass through the hypoglossal canal

Question 16

describe the sensory and motor functions of cranial nerve IX

Answer 16

sensory: upper pharynx/ taste - posterior 1/3 of tongue/ carotid sinus/ body (blood pressure/ composition)
motor: pharyngeal muscle and parotid gland

Question 17

describe the motor and parasympathetic functions of cranial nerve X

Answer 17

motor: larynx (speech)/ pharynx (swallowing)
parasympathetic: heart rate/ blood pressure/ bronchioles constriction/ gut sensation (peristalsis/ segmentation/ secretion)

Question 18

describe the two parts of the spinal accessory nerve

Answer 18

cranial part - continuation of vagus nerve

spinal part - suplies the sternocleidomastoid and trapezius muscles

Question 19

which muscles does cranial nerve XII supply?

Answer 19

muscles of the tongue