Cranial Nerves Q7

Question 1

Where is ventral and dorsal of the brain?

Answer 1

Ventral is bottom of head and dorsal is top of head.

Question 2

ID the cranial nerves and name them.

Answer 2

CN I - Olfactory nerve

CN II - Optic nerve

CN III - Oculomotor nerve

CN IV - Trochlear nerve

CN V - Trigeminal nerve

CN VI - Abducens nerve

CN VII - Facial nerve

CN VIII - Vestibulocochlear nerve

CN IX - Glossopharyngeal nerve

CN X - Vagus nerve

CN XI - Accessory nerve

CN XII - Hypoglossal nerve

Question 3

CN I is a protursion of what structure? What is its function?

Answer 3

Extension of the telenchephalon. Only sense is olfaction. Exits via cribriform foramina.

Question 4

CN II is part of what structure? What is its function?

Answer 4

Part of the diencephalon. Only sense is vision. Exits via optic canal.

Question 5

What is CN III? Where does it exit and what does it innervate?

Answer 5

Oculomotor nerve. Exits via superior orbital fissure and innervates somatic motor of levator palpebrae superioris and all the muscles of the eye except lateral rectus and superior oblique. Visceral motor is pupillary sphincter and cilliary muscle.

Question 6

What is CN IV? What does it innervate and where does it exit?

Answer 6

Trochlear nerve. Innervates superior oblique and exits out the superior orbital fissure. Note that it is the only nerve to emerge from dorsal surface.

Question 7

What is CN VI? What does it innervate and where does it exit?

Answer 7

Abducens nerve. Only innervate lateral rectus and exits via superior orbital fissure.

Question 8

What is CN V1? Where does it exit from, what are the three branches, and what does it innervate?

Answer 8

Trigeminal, opthalmic branch. Exits via superior orbital fissure and divides into frontal, nasociliary, and lacrimal nerve. Only does sensory of these locations.

Question 9

What is CN V2? Where does it exit from, what are the branches, and what does it innervate?

Answer 9

Trigeminal nerve maxillary branch. Exits via foramen rotundum and branches into posterior, middle, and anterior alveolar nerves, infraorbital nerve, and zygomatic nerve. Innervate sensory of maxillary teeth, eyelid, lower eyelid, temple and cheeks.

Question 10

What is CN V3? Where does it exit from, what are the three branches, and what does it innervate?

Answer 10

Trigeminal nerve mandibular branch. Exits via foramen ovale and branches into buccal, massateric, deep temporal, pterygoid, inferior alveolar, and lingual nerves. General sensory of oral mucosa, anterior 2/3 tongue, and floor of mouth.

Question 11

What is the chorda tympani? What does it innervate and where is it found?

Answer 11

It is a branch of CN VII, runs with the lingual nerve, and innervates the submandibular and sublingual glands and taste for anterior 2/3 of tongue.

Question 12

What does the inferior alveolar nerve innervate?

Answer 12

Mylohyoid, anterior belly diagastric,

Question 13

What is CN VII? What are the branches? What does it innervate?

Answer 13

Facial nerve. Branches into temporal, zygomatic, buccal, cervical and posterior auricular. Innervates all the glands of the face except the parotid.

Question 14

Where does the greater petrosal nerve run? What does it innervate?

Answer 14

It is a branch of CN VII that links with CN V2 and innervate the lacrimal and nasal glands.

Question 15

What is CN VIII? What does it innervate? Where does it exit?

Answer 15

Vestibulochochlear nerve. It is the special sensory of hearing and balance. Exits via the internal acoustic meatus.

Question 16

What is CN IX? What does it innervate and where does it exit?

Answer 16

Glossopharyngeal nerve. Exits via jugular foramen.

Moto: Pharyngeal constrictor, stylopharnygeus, parotid gland.

Sensory: Posterior 1/3 tongue, posterior oral pharynx, mucosa, middle ear, external ear, tympanic membrane.

Special sensory: Taste post. 1/3 tongue chemo and baro receptors carotid sinus.

Question 17

What is the branch of the glossopharyngeal nerve that innervates the parotid gland?

Answer 17

Lesser petrosal nerve.

Question 18

What is CN X? Where does it exit from and what does it innervate?

Answer 18

Vagus nerve. Exits via the jugular foramen.

Sensory: Viscera in abdomen, laryngopharynx, larynx, posterior cranial fossa, ear and external acoustic meatus, epiglottis taste.

Motor: Pharyngeal constrictors

Special: Pressure receptors, chemo receptors aorta.

Question 19

What is CN XI? Where does it exit and what does it innervate?

Answer 19

Spinal accessory nerve. Notice that it extends into foramen magnum from spinal cord and exits via the jugular foramen.

Motor to the SCM and Trap.

Question 20

What is CN XII? Where does it exit and what does it innervate?

Answer 20

Hypoglossal nerve. Exits via the hypoglossal canal.

Motor to the tongue muscles.