Cranial Nerves

Question 1

Cribriform plate diseases

Answer 1

Nasal origin: nasal tumors, destructive rhinitis
Intracranial: esthesioneuroblastoma, cranial trauma (dural tears, CSF rhinorrhea, olfactory bulb separation)

Question 2

What is the optic nerve derived from?

Answer 2

Outgrowth of brain = white matter tract myelinated by oligodendrocytes

Question 3

Sequences best for optic nerve identification?

Answer 3

Dorsal images with fat suppression

Question 4

Where is the optic chasm located?

Answer 4

Ventral to hypothalamus & rostral to hypophyseal infundibulum

Question 5

In general, how do disease affect the optic nerve?

Answer 5

Cause demyelination

Question 6

What are the MRI findings of optic nerve disease?

Answer 6

Swelling, altered signal intensity, & contrast enhancement of the optic nerve

Question 7

What is the common tumor of the optic nerve?

Answer 7

Meningioma (arises from dural sheath)

Question 8

Exit of olfactory nerve (I)

Answer 8

Cribriform plate (ethmoid bone)

Question 9

What is important about the trochlear nerve at level of brainstem?

Answer 9

Only CrN to emerge DORSALLY

Question 10

What are the 3 branches of the trigeminal nerve (V)?

Answer 10

Ophthalmic, Maxillary, Mandibular

Question 11

Where does the ophthalmic nerve exit?

Answer 11

Orbital fissure

Question 12

Where does the maxillary nerve exit?

Answer 12

Round foramen, alar canal, & rostral alar foramen

Question 13

Where does the mandibular nerve exit?

Answer 13

Oval foramen

Question 14

Mandibular nerve is motor to what?

Answer 14

Muscles of mastication

Question 15

What are the 6 muscles of mastication?

Answer 15

Masseter, Temporalis, Rostal digastricus, Medial & lateral pterygoids, & mylohyoideus

Question 16

Where does the abducens nerve exit (VI)?

Answer 16

Orbital fissure

Question 17

What nerve innervates the caudal belly of the digastricus?

Answer 17

Facial

Question 18

Where does the facial nerve (VII) exit?

Answer 18

Internal acoustic meatus (along w/ vestibular & cochlear nn)

Question 19

Name the CrN in order from 1 to 12

Answer 19

1 - Olfactory, 2- Optic, 3 - Oculomotor, 4- Trochlear, 5- Trigeminal, 6- Abducens, 7- Facial, 8- Vestibulocochlear, 9- Glossopharyngeal, 10 - Vagus, 11- Accessory, 12- Hypoglossal

Question 20

What dysfunction results from CrN 1?

Answer 20

Loss of smell

Question 21

What is the entrance of CrN 1?

Answer 21

Cribriform foramina

Question 22

What dysfunction results from CrN 2?

Answer 22

Loss of vision

Question 23

What 4 things are contained within the orbital fissure?

Answer 23

CrN3 (exrtraoc, ciliary, pupil)
CrN 4 (dorsal obl m)
CrN 5 - ophthalmic branch (sensory to cornea, nasal cavity, & periocular skin)
CrN 6 (motor lateral rectus & retractor bulbi)

Question 24

What is contained within the rostral alar foramen?

Answer 24

Maxillary artery & maxillary branch of CrN 5

Question 25

What is contained within the caudal alar foramen?

Answer 25

Maxillary artery

Question 26

What are the motor & sensory functions of the mandibular branch of CrN 5?

Answer 26

Motor to muscles of mastication
Sensory to rostral tongue, lower cheek, & jae

Question 27

What is the function of the hypoglossal nerve?

Answer 27

Motor to tongue, vocalization & swallowing

Question 28

What is the function of the facial nerve?

Answer 28

Motor to muscles of facial expression, taste to rostral 1/3, parasympathetic to salivary glands

Question 29

What is the function of the glossopharyngeal nerve?

Answer 29

Taste to caudal 1/3, motor to pharynx to allow for swallowing, salivation

Question 30

What is the function of the vagus nerve?

Answer 30

Motor to pharynx (along w/ CrN 9), larynx (recurrent laryngeal n), parasympathetic to viscera of neck/thorax/abdomen