cranial nerves I-VI

Question 1

what is the order of the cranial nerves

Answer 1

I. Olfactory 
II. Optic
III. Oculomotor 
IV. Trochlear 
V. Trigeminal 
VI. Abducens 
VII. Facial 
VIII. Vestibulocochlear 
IX. Glossopharyngeal 
X. Vagus 
XI. Accessory 
XII. Hypoglossal

Question 2

what are the types of sensory functions of the CN’s

Answer 2

• somatic; general sensation
• Special sensations; smell, sight, hearing, balance, taste
• Autonomic, e.g. sensing blood pressure

Question 3

what are the types of motor functions of the CN’s

Answer 3

• Somatic & Branchial; skeletal muscle

* Autonomic; smooth muscle + glands

Question 4

I. Olfactory

Answer 4

• Sense of smell; special
• Cribriform plate
• Entorhinal cortex in the anterio-medial part of the temporal lobe
Testing: scratch and sniff, scent bottles
Disease: olfactory groove meningioma, Parkinson’s, Epilepsy, Trauma (anosmia)

Question 5

II. Optic

Answer 5

• Vision; special sense
• Optic canal
• Complex pathway to the occipital cortex
Testing: testing visual fields, pupil reflex, light reflex (both pupils constrict), accommodation, visual acuity, fundoscopy
Disease: syphilis (slow accommodation) Edinger Westphal nucleus damage, Horner’s syndrome (sympathetic damage), Halmes-Adie pupil (parasympathetic damage

Question 6

III. Oculomotor

Answer 6

• Superior rectus
• Inferior rectus
• Medial rectus
• Inferior rectus
• Parasympathetic – pupil + focus lens

Question 7

IV. Trochlear

Answer 7

• Superior oblique

Question 8

V. Trigeminal

Answer 8

• Sensation to face and mouth
• Muscles of mastication (mandibular): temporalis, masseter, pterygoids
• Branches: ophthalmic, maxillary, mandibular
Testing: test sensation, clench teeth – feel muscles
Disease: trigeminal neuralgia

Question 9

VI. Abducens

Answer 9

• Lateral rectus

Question 10

which cranial nerves have an autonomic function and give off parasympathetic fibres?

Answer 10

III. Oculomotor 
VII. Facial 
IV. Glossopharyngeal 
V. Vagus 
(1973)

Question 11

anatomy of CN III

Answer 11

Exits midbrain,
near Posterior cerebral arteries,
passes alongside cavernous sinus,
through superior orbital fissure,
branches into two.

Question 12

anatomy of CN IV

Answer 12

Exits midbrain dorsally,
Passes round to the front,
near Posterior cerebral arteries,
passes alongside cavernous sinus,
through superior orbital fissure.

Question 13

anatomy of CN VI

Answer 13

Exits between the pons and medulla,
passes from the posterior to middle cranial fossa,
passes alongside cavernous sinus,
through superior orbital fissure.

Question 14

anatomy of CN V

Answer 14

Exits from pons,
passes directly into Meckle’s cave where it divides into three;
Opthalmic branch passes through superior orbital fissure
Maxillary branch; foramen rotundum
Mandibular branch; foramen ovale.