The Upper Cranial Nerves

Question 1

What cranial nerve(s) arise from the diencephalon?

Answer 1

Cranial nerve II

Question 2

What cranial nerve(s) arise from the mesencephalon (midbrain)?

Answer 2

Cranial nerves III and IV

Question 3

What cranial nerve(s) arise from the pons?

Answer 3

Cranial nerves V, VI, VII, and VIII

Question 4

What cranial nerve(s) arise from the medulla?

Answer 4

Cranial nerves IX, X, XI, and XII

Question 5

Where is the olfactory epithelium seen?

Answer 5

It is found in the roof of the nasal cavity, extending inferolaterally on the superior turbinate and inferomedially on the nasal septum.

Question 6

This is the rostral enlargement of the olfactory tract; It is a bulbous structure that lies on the intracranial surface of the cribriform plate.

Answer 6

Olfactory bulb

Question 7

This is the centrally projecting axons that convey olfactory information to the medial and lateral olfactory areas, which are the two main central projection of the rhinencephalon.

Answer 7

Olfactory tract

Question 8

Movements of the eye are produced by the six extraocular muscles innervated by what cranial nerves?

Answer 8

Cranial nerves III, IV, and VI

Question 9

The oculomotor nerve nuclear complex (oculomotor nucleus and associated parasympathetic, Perlia’s and Edinger-Westphal nuclei) is located where?

Answer 9

It is found in the motor column of the basal plate of the rostral midbrain at the level of the superior colliculum wedge between the periaqueductal gray matter and the medial longitudinal fasiculus near the midline.

Question 10

Where is the trochlear nuclei located?

Answer 10

It is located in the midline of the same basal plate motor column as the oculomotor nerve, just caudal to the third nerve nuclear complex.

Question 11

What does the trochlear nerve innervate?

Answer 11

Superior oblique muscle

Question 12

Where is the abducens nucleus located?

Answer 12

In the pontine tegmentum near the midline, just ventral to the fourth ventricle.

Question 13

Axons of the facial nerve loop around the abducen nucleus, creating a bulge in the floor of the fourth ventricle called what?

Answer 13

Facial colliculus

Question 14

The cisternal abducen nerve ascends anterior to the belly of the pons to pierce the dura covering the posterior sphenoid bone at what canal?

Answer 14

Dorello’s canal

Question 15

This is the largest of the cranial nerves and has both sensory and motor functions.

Answer 15

Trigeminal nerve

Question 16

Motor innervation of the trigeminal nerve is what branch?

Answer 16

Seen in the mandibular division (V3)

The four muscles of mastication as well as the anterior belly of the digastric, mylohyoid, tensor tympani, and tensor palatini muscles are all innervated by cranial nerve V3.

Question 17

What are the four brain stem nuclei that contributes to the trigeminal nerve?

Answer 17

1. Mesencephalic nucleus. Proprioception from the face
2. Main sensory nucleus. Tactile sensation from the face
3. Motor nucleus. Motor inner vation of the muscles of mastication, tensor palatini and tensor tympani muscles, and the mylohyoid and anterior belly of the digastric musces.
4. Spinal nucleus. Pain and temperature from the face

Question 18

The trigeminal nerve emerges from the lateral pons at a point referred to as what?

Answer 18

The root entry zone

Question 19

The only branch of trigeminal nerve that carries both sensory and motor fibers

Answer 19

Maxillary branch (V3)