CRANIAL NERVES Flashcards
What are the 12 cranial nerves?
1) Olfactory
2) Optic
3) Oculomotor
4) Trochlear
5) Trigeminal
6) Abducense
7) Facial
8) Vestibulocochlear
9) Glossopharyngeal
10) Vagus
11) Accessory
12) Hypoglossal
Where does the olfactory nerves exit the skull?
Via cribiform plate of ethmoid bone
Where does the optic nerve leave the skull?
Optic canals
Where does the oculomotor nerve exit the skull?
Superior Orbital fissure
Where does the oculomotor nerve originate?
Originates from the medullary pontine junction and passes through the interpeduncular fossa.
what is the function of the ocumlomotor nerve (III) ?
- motor controll to most of the extra-ocular muscles
- sphincter pupillae (pupil constriction)
- ciliary muscles (adjust lens)
Where does the trochlear nerve (IV) originate from?
midbrain (it is the only nerve to arise from the dorsal brainstem)
Where does the trochlear nerve exit the skull?
Superior Orbital fissure?
What is the function of the trochlear nerve?
Innervates the superior oblique muscle
(which it depresses, abducts and medially rotates the eye)
Describe the 3 branches of the trigeminal nerve.
V1 = Opthalmic (exits via superior orbital fissure) V2 = Maxillary (exits via foramen rotundum) V3 = Mandibular (exits via foramen Ovale)
V1, V2, V3 are all sensory branches.
V3 has motor fibres which supply the muscles of mastication including anterior belly of DIGASTRIC and MYLOHYOID
What muscles do the motor fibres of V3 supply?
- anterior belly of DIGASTRIC
- MYLOhyoid
What is the function of the ABDUCENT (VI) nerve?
supplies motor innervation to LATERAL RECTUS.
lateral rectus is an oculomotor muscle that causes ABDUCTION of the eyeball
Where does the Abducent nerve exit the skull?
superior orbital fissure
Where does the Abducent nerve arise from?
PONTO-MEDULLARY junction
Where does the FACIAL nerve arise from?
Cerebellar Pontine angle
Where does the facial nerve exit the skull?
First goes through the INTERNAL ACOUSTIC MEATUS and then exits skull via the STYLOMASTOID FORAMEN
What is the funtion of the facial nerve?
- Taste sensation from ANTERIOR 2/3 of tongue
- innervates lacrimal, submandibular and sublingual glands
- motor to facial muscles
- motor to STYLOHYOID
- motor to posterior belly of DIGASTRIC
Where does the Vestibulocochlear nerve (VIII) emerge from ?
Cerebellar pontine angle
What is the function of the Vestibulocochlear nerve?
supplies the hearing and balance apparatus
Where does the vestibulocochlear nerve leave the cranial cavity?
INTERNAL ACOUSTIC MEATUS
enters the petrous part of the temporal bone
What is the function of the glossopharyngeal nerve?
- sensory input from POSTERIOR 1/3 of Tongue
- Sensory input from Palative Tonsils / oropharynx
- Taste from POSTERIOR 1/3 of Tongue
- Stimulate PAROTID gland
Where does the Glossopharyngeal Nerve exit the skull?
Jugular Foramen
What is the function of the Vagus nerve?
- sensory from larynx
- thoracic and abdo
Where does the vagus nerve exit the skull?
Jugular Foramen
What muscles does the accessory nerve innervate?
Trapezius
sternocleidomastoid
Where does the accessory nerve leave the skull?
Jugular Foramen
What is the function of the hypoglossal nerve?
-MOTOR to muscles of TONGUE
What does the hypoglossal nerve pass through?
HYPOGLOSSAL CANAL
