Cranial nerves

Question 1

Cranial nerve I- Olfactory

Answer 1

Sensory
CNS origin- Cerebrum
Skull base foramen- Cribriform plate
Function- Olfaction (smell)

Question 2

Cranial nerve II- Optic

Answer 2

Sensory
CNS origin- Diencephalon
Skull base foramen- Optic canal
Function- Sight

Question 3

Cranial nerve III- Oculomotor

Answer 3

Motor (+Parasympathetics)
CNS origin- Midbrain
Skull base foramen- Superior orbital fissure
Function- Eye movements (SR, IR, MR, IO), eyelid opening (LPS), pupillary constriction and accommodation.

Question 4

Cranial nerve IV- Trochlear

Answer 4

Motor
CNS origin- Midbrain
Skull base foramen- Superior orbital fissure
Function- Eye movements (SO)

Question 5

Cranial nerve V- Trigeminal (V1)

Answer 5

Motor and Sensory
CNS origin- Pons
Skull base foramen- ophthalmic – superior orbital fissure.
Function- sensation from the upper third of face.

Question 6

Cranial nerve V- Trigeminal (V2)

Answer 6

Motor and Sensory
CNS origin- Pons
Skull base foramen- Maxillary- foramen rotundum
Function- sensation from the middle third of face

Question 7

Cranial nerve V- Trigeminal (V3)

Answer 7

Motor and Sensory
CNS origin- Pons
Skull base foramen- Mandibular- foramen ovale
Function- sensation from the lower third of face, motor to the muscles of mastication, motor to the tensor tympani muscle.

Question 8

Cranial nerve VI- Abducens

Answer 8

Motor
CNS origin- Pons
Skull base foramen- Superior orbital fissure
Function- Eye movements

Question 9

Cranial nerve VII- Facial

Answer 9

Sensory and Motor (+parasympathetic)
CNS origin- Pons
Skull base foramen- Internal auditory meatus then stylomastoid foramen
Function- Motor to the muscles of facial expression, motor to the stapedius muscle, sensation from the ear canal, secretomotor function to the submandibular and sublingual salivary glands and lacrimal gland, taste from the anterior 2/3 of the tongue.

Question 10

Cranial nerve VII- Vestibulocochlear

Answer 10

Sensory
CNS origin- Pons
Skull base foramen- Internal auditory meatus
Function- Balance and hearing.

Question 11

Cranial nerve IX- Glossopharyngeal

Answer 11

Sensory and Motor (+parasympathetics)
CNS origin- Medulla
Skull base foramen- Jugular foramen
Function- Motor to the stylopharyngeus muscle, sensation from the pharynx and posterior 1/3 of the tongue, sensation from the carotid baroreceptors, secretomotor function to the parotid salivary gland, taste from the posterior 1/3 of the tongue.

Question 12

Cranial nerve X- Vagus

Answer 12

Sensory and motor (+parasympathetics)
CNS origin- Medulla
Skull base foramen- Jugular foramen
Function- Motor to the muscles of the soft palate, pharyngeal muscles and internal laryngeal muscles, sensation from the external ear and ear canal, taste from the epiglottis and parasympathetics to the thoracic and abdominal organs.

Question 13

Cranial nerve XI- Accessory

Answer 13

Motor
CNS origin- Spinal cord C1-C5
Skull base foramen- Foramen magnum (in) and jugular foramen (out)
Function- Motor to the trapezius and sternocleidomastoid muscles.

Question 14

Cranial nerve XII- Hypoglossal

Answer 14

Motor
CNS origin- Medulla
Skull base foramen- Hypoglossal canal
Function- Motor to the muscles of the tongue.