Cranial nerves

Question 1

Name the cranial nerves.

Answer 1

CNI: olfactory
CNII: optic
CNIII: oculomotor
CNIV: trochlear
CNV: trigeminal (V1, V2 and V3)
CNVI: abducens
CNVII: facial
CNVIII: vestibulocochlear
CNVIX: glossopharyngeal
CNX: vagus
CNXI: accessory
CNXII: hypoglossal

Question 2

Which fibres do each CN carry?

Answer 2

CNI: olfactory - sensory
CNII: optic - sensory
CNIII: oculomotor - motor
CNIV: trochlear - motor
CNV: trigeminal (V1, V2 and V3) - both
CNVI: abducens - motor
CNVII: facial - both
CNVIII: vestibulocochlear - sensory
CNVIX: glossopharyngeal - both
CNX: vagus - both
CNXI: accessory - motor
CNXII: hypoglossal - motor

Question 3

What do somatic motor fibres supply?

Answer 3

Striated muscle

Question 4

What do visceral motor fibres supply?

Answer 4

Cranial division of parasympathetic supply. Innervates smooth muscle and glands.

Question 5

What do visceral sensory fibres supply?

Answer 5

Not normally conscious - afferent inputs from pharynx, larynx, gut, heart etc.

Question 6

What do general sensory fibres supply?

Answer 6

Afferent inputs (touch, temperature and pain) from skin and mucous membranes.

Question 7

What do special sensory fibres supply?

Answer 7

Taste, smell, vision, hearing and balance.

Question 8

What are the openings of each cranial nerve?

Answer 8

CNI: olfactory - cribiform plate of ethmoid
CNII: optic - optic canal
CNIII: oculomotor - superior orbital fissure
CNIV: trochlear - superior orbital fissure
CNV: trigeminal - VI (opthalmic): superior orbital fissure; V2 (maxillary): foramen rotundum; V3 (mandibular): foramen ovale
CNVI: abducens - superior orbital fissure
CNVII: facial - internal acoustic meatus
CNVIII: vestibulocochlear - internal acoustic meatus
CNVIX: glossopharyngeal - jugular foramen
CNX: vagus - jugular foramen
CNXI: accessory - jugular foramen
CNXII: hypoglossal - hypoglossal canal