8.1 Cranial Nerves III, V and VII

Question 1

Where does the oculomotor nerve originate from?

Answer 1

Anterior midbrain

Question 2

Which two arteries does the oculomotor nerve pass through as it leaves the brain?

Answer 2

Inferior to cerebral artery

Superior to superior cerebellar artery

Question 3

Which layer does the oculomotor nerve pierce to enter the cavernous sinus?

Answer 3

Dura mata

Question 4

Via which fossa does the oculomotor nerve exit the cranial fossa?

Answer 4

Superior orbital fissure

Question 5

Name the 2 structures that the superior branch of the oculomotor nerve innervates

Answer 5

Superior rectus muscle
Levator palpabrae superioris muscle
Sympathetic- superior tarsal muscle

Question 6

Name the 2 structures that the inferior branch of the oculomotor nerve innervates

Answer 6

Inferior rectus
Medial rectus
Inferior oblique
Parasympathetic- sphincter pupillae + ciliary muscles

Question 7

Where does the trigeminal nerve originate from?

Answer 7

3 sensory nuclei and 1 motor nucleus from the midbrain to the medulla

Question 8

Where does the sensory root of the trigeminal nerve form?

Answer 8

At the level of the Pons

Question 9

When does the sensory root become the trigeminal ganglion?

Answer 9

Middle cranial fossa, lateral to the cavernous sinus

Question 10

To which branch of the trigeminal nerve is the motor root distributed to?

Answer 10

V3- mandibular nerve

Question 11

Name the 3 branches of the trigeminal nerve

Answer 11

V1- opthalmic
V2- maxillary
V3- mandibular

Question 12

Where does the ophthalmic nerve exit the cranial cavity?

Answer 12

Superior orbital fissure

Question 13

Where does the maxillary nerve exit the cranial cavity?

Answer 13

Foramen rotundum

Question 14

Where does the mandibular nerve exit the cranial cavity?

Answer 14

Foramen ovale –> Infra-temporal fossa

Question 15

What are the 3 branches of the ophthalmic nerve?

Answer 15

Frontal
Lacrimal
Nasocilary

Question 16

Which area of the face does V1 innervate?

Answer 16

Skin and mucous membranes of scalp, forehead, dorsum of nose, cornea, upper eyelid, conjunctiva, frontal and ethmoidal sinuses

Question 17

Which area of the face does V2 innervate?

Answer 17

Skin and mucous membranes of fronto-nasal prominence derivatives
Lower eyelid, conjunctiva, cheeks, maxillary sinus, nasal cavity, upper lip, superior palate, upper molars, incisors and canines

Question 18

Which area of the face does V3 give sensory innervation to?

Answer 18

Skin, mucous membranes and striated muscle derivatives of the mandibular prominence:
Floor of oral cavity, external ear, lower lip, chin, anterior 2/3rds tongue, lower molar, incisor and canines

Question 19

Which area of the face does V3 give motor innervation to?

Answer 19

Muscles of mastication, anterior belly of digastric, mylohyoid, tensor veli palatini, tensor tympani

Question 20

Which structures do the parasympathetic fibres which run with the trigeminal nerve innervate?

Answer 20

Submandibular and sublingual glands
Parotid gland
Lacrimal gland
Mucous glands in nasal cavity

Question 21

Where does the facial nerve originate from?

Answer 21

Large motor root in the Pons and a small sensory root

Question 22

Which fossa do the roots of the facial nerve travel through as they leave the Pons?

Answer 22

Internal acoustic meatus in the temporal bone

Question 23

Where do the roots fuse?

Answer 23

Facial canal

Question 24

What is the name of the ganglion that the facial nerve forms?

Answer 24

Geniculate ganglion

Question 25

Name the 3 nerves which the facial nerve gives off after the geniculate ganglion

Answer 25

Greater Petrosal Nerve Nerve to stapedius Chorda tympani

Question 26

What does the facial nerve go through to exit the facial canal?

Answer 26

Stylomastoid foramen

Question 27

Which nerves branch from the facial nerve when it is extracranial?

Answer 27

Posterior auricular Nerve to digastric Nerve to stylohyoid

Question 28

Where does the motor root of the facial nerve split into branches?

Answer 28

Parotid gland

Question 29

Name the 5 motor branches of the facial nerve

Answer 29

``` Temporal Zygomatic Buccal Marginal Mandibular Cervical ```

Question 30

What do the motor nerve branches of the facial nerve innervate?

Answer 30

Muscles of facial expression- derivatibes of the 2nd pharyngeal arch

Question 31

What special sensory innervation is the chorda tympani responsible for?

Answer 31

Taste sensation in anterior 2/3rds of tongue

Question 32

What is the corneal reflex?

Answer 32

Involuntary blinking of the eyelids stimulated by tactile, thermal or painful stimulation of the cornea.

Question 33

What is the afferent limb of the corneal reflex?

Answer 33

Opthalmic nerve (V1)

Question 34

What is the efferent limb of the corneal reflex?

Answer 34

Facial nerve

Question 35

Describe how a oculomotor nerve lesion will present

Answer 35

Ptosis Down and out eyeball Dilated pupil

Question 36

Describe how a trigeminal nerve lesion will present

Answer 36

Cannot look laterally

Question 37

Describe how an intercranial facial nerve lesion will present

Answer 37

Facial muscles of expression paralysed Reduced salivation and loss of taste sensation Hypersensitive to sound Reduced lacrimal fluid production

Question 38

Describe how an extracranial facial nerve lesion will present

Answer 38

Paralysis or weakening of the muscles of facial expression ONLY