Cranial Nerves

Question 1

where does the olfactory nerves enter the skull

Answer 1

through the cribriform plate of the ethmoid bone, then forms the olfactory bulb

Question 2

where do the optic nerves exit the skull

Answer 2

at the optic foramen, near the pituitary stalk

Question 3

where does the oculomotor nerve leave the skull

Answer 3

supraorbital fissure

Question 4

where does the trochlear nerve exit the skull

Answer 4

supraorbital fissure

Question 5

where does the trigeminal nerve branches exit the skull

Answer 5

opthalmic branch - supraorbital fissure
maxillary branch - foramen rotundum
mandibular branch - foramen ovale

Question 6

where does the abducens nerve exit the skull

Answer 6

supraorbital fissure

Question 7

what nerve(s) exit the skull at the internal auditory meatus

Answer 7

facial nerve and vestibulocochlear nerves

Question 8

what nerve(s) exit the skull at the jugular foramen

Answer 8

glossopharyngeal, vagus and accessory as the spinal root of accessory enters through foramen magnum to join

Question 9

where does the hypoglossal nerve exit the skull

Answer 9

the hypoglossal foramen

Question 10

what structure enters the skull through the foramen magnum

Answer 10

vertebral artery

Question 11

what is trigeminal neuralgia

Answer 11

extreme facial pain

Question 12

what is an infection that can lie dormant on a nerve and why is this dangerous

Answer 12

shingles can lie dormant on the trigeminal ganglion, can then go through either division of the trigeminal nerve. if it spreads through opthalmic, can cause scarring on the cornea.

Question 13

what nerves run through the supraorbital fissure

Answer 13

ocluomotor, trochlear, abducens, opthalmic division of trigeminal

Question 14

what muscle does the trochlear nerve innervate

Answer 14

superior oblique muscle

Question 15

what muscle does the abducens nerve innervate

Answer 15

lateral rectus

Question 16

what muscle does the oculomotor nerve innervate

Answer 16

medial rectus, and hold eye up - superior

Question 17

what muscle works to constrict the pupil and what nerves supply this

Answer 17

pupilli constrictor muscle - oculomotor nerve but parasympathetic fibres

Question 18

what nerves provide sensation to the face

Answer 18

opthalmic division - supraorbital nerve
maxillary division - infraorbital nerve, zygomaticofacial nerve, zygomaticotemporal nerve
mandibular - auriculotemporal, buccal and mental

Question 19

what would you be concerned about if facial nerve was paralysed

Answer 19

orbicularis oculi paralysed - unable to blink to protect eye. would provide an eye patch to protect the cornea

Question 20

how might the facial nerve be damaged during surgery to remove schwanoma of vestibulocochlear nerve

Answer 20

facial nerve also exits the skull at the internal acoustic meatus so runs close to the CN VIII. uses suboccipital retrosigmoid approach

Question 21

what is horners syndrome

Answer 21

damage to sympathetic trunk in neck

Question 22

what nerves come from the anterior division of the mandibular division of trigeminal

Answer 22

masseter nerve, deep temporal nerves to temporalis, lateral pterygoid nerve - then forms the buccal nerve for sensory innervation to cheek and gingiva

Question 23

what nerves come from the posterior division of the mandibular division of trigeminal

Answer 23

auriculotemporal nerve, inferior alveolar nerve - mylohyoid nerve and mental nerve. lingual nerve

Question 24

what is the chorda tympani nerve

Answer 24

supplies taste sensation to anterior 2/3rds of tongue, and parasympathetic supply to submandibular and sublingual glands, runs through lingual nerve but then leaves to join facial nerve and synapse at facial ganglia in brainstem

Question 25

describe the innervation to submandibular and sublingual glands

Answer 25

parasympathetic supply in chorda tympani - joins facial nerve. synapse at lingual nerve ganglia - post ganglionic fibres then leave and enter submandibular and sublingual gland to cause secretion