Cranial Nerves

Question 1

How many cranial nerves are there?

Answer 1

there are 12 pair and they are shown as CN–Roman numerals–

Question 2

What are their main functions?

Answer 2

They have 5 main functions

Motor - Somatic (efferents)
- Visceral motor (efferent and parasympathetic)

Sensory - General sensory (afferent - touch, pain, temp)

           - Visceral sensory (afferent)
           - Special sensory

Question 3

what is the mnemonic to remember all the nerves

Answer 3

On Old Olympus’ Towering Top, A Fat Vicious Goat Vandalised A Hat.

On = Olfactory Nerve
Old = Optic Nerve
Olympus' = Oculomotor Nerve
Towering = Trochlear Nerve 
Top = Trigeminal Nerve
A = Abducent Nerve 
Fat = Facial Nerve 
Vicious = Vestibulocochlear Nerve 
Goat = Glossopharyngeal Nerve
Vandalised Vagus Nerve
A = Accessory Nerve
Hat = Hypoglossal Nerve

Question 4

The mnemonic for the sensory/motor for cranial nerves

Answer 4

Some Say Money Matters, But My Brother Says Big Brains Matter More

Sensory - Olfactory 
Sensory - Optic nerve
Motor - Oculomotor 
Motor - Trochlear
Both - Trigeminal 
Motor - Abducant
Both - Facial
Sensory - Vestibulocochlear
Both - Glossopharyngeal 
Both - Vagus
Motor - Accessory
Motor - Hypoglossal

Question 5

Olfactory Nerve

Origin
Ends
Passage
Function

Answer 5

Originates within the mucosa of the nasal cavity

ends olfactory bulb

passage through the cribriform plate of the ethmoid

helps with smell

Question 6

Optical Nerve

Origin
Ends
Passage
Function

Answer 6

begins in the sclera of eye

mid brain

Through optical canal

Sight

Question 7

Oculomotor

Origin
Ends
Passage
Function

Answer 7

midbrain

muscles of the eye

SOF (superior orbital fissure)

Innervation of the muscle that interacts with the eye

Question 8

Trochlear (smallest diameter nerve but longest intracranial pathway)

Origin
Ends
Passage
Function

Answer 8

midbrain

superior oblique muscle

SOF

innervation of the superior oblique muscle

Question 9

Trigeminal

Origin
Ends
Passage
Function

Answer 9

Pons

Ophthalmic- eye
The maxillary - upper jaw
Mandibular - Lower jaw

Ophthalmic- SOF
Maxillary - Foramen rotundu
Mandibular - Foramen ovale

Ophthalmic and maxillary are sensory
Mandibular is a blend - innervates the TMJ muscles

Question 10

Abducent

Origin
Ends
Passage
Function

Answer 10

pons

Lateral Rectus muscle

SOF

Lateral Rectus muscle

Question 11

Facial Nerve (longest intraosseous CN)

Origin
Ends
Passage
Function

Answer 11

junction of the pons and medulla

through internal acoustic meatus, the facial canal within the temporal bone exits through the stylomastoid foramen. enters the parotid gland where it gives rise to the terminal branches of the facial expression.

Posterior auricular 
Temporal 
Zygomatic 
Buccal 
Mandibular
Cervical

Question 12

Vestibulocochlear (auditory nerve) (the only nerve not to leave the skull

Origin
Ends
Passage
Function

Answer 12

The junction between pons and medulla

ear

enters internal acoustic meatus, separates into the vestibular and cochlear nerve

Vestibular - balance
Cochlear hearing

Question 13

Glossopharyngeal nerve
Glosso = tongue
Pharyngeal = throat

Origin
Ends
Passage
Function

Answer 13

emerges from the medulla

tongue

jugular foramen

Sensory - posterior 1/3 of tongue for taste
- mucosa of pharynx, palatine and tonsils
Motor - stylopharyngeus
Proprioception - stylopharyngeus

Question 14

Vagus nerve (Longest nerve)

Origin
Ends
Passage
Function

Answer 14

series of roots from medulla

through jugular foramen

sensory -pharynx, largyn (Throat), Thoracic and abdominal organs

special - taste

somatic - soft palate, pharynx, intrinsic layngeal and palatoglossus

Question 15

Accessory nerve

Origin
Ends
Passage
Function

Answer 15

cranial root, medulla

SCM, Traps

Jugular foramen

innervates the SCM and traps

Question 16

Hypoglossal nerve

Origin
Ends
Passage
Function

Answer 16

medulla

hypoglossal canal

Motor of the tongue