M13: Cranial Nerves Formina/What They Pass Through

Question 1

What does the olfactory nerve (CN I) pass through?

Answer 1

Foramina of the Cribfriform Plate (of the Ethmoid)

Question 2

What does the Optic Nerve (CN II) pass through?

Answer 2

Optic Canal(s) of the Sphenoid

Question 3

What does the Oculomotor Nerve (III) pass through?

Answer 3

Superior Orbital Fissure of Sphenoid

Question 4

What does the Trochlear Nerve IV pass through?

Answer 4

Superior Orbital Fissure of Sphenoid

Question 5

What structures does the Trigeminal Nerve (V) pass through?

Answer 5

superior orbital fissure

foramen ovale

foramen rotundum

Note: there are three divisions of the trigeminal nerve and each passes through a different opening/exit in the skull

Question 6

What does the abducens nerve (VI) pass through?

Answer 6

superior orbital fissure of sphenoid

Question 7

What does the facial nerve (VII) pass through?

Answer 7

internal acoustic meatus and facial canals

Bonus: in the figure it #22 is the internal acoustic meatus, and we don’t have to identify the facial canals

Question 8

What does the vestibulochcohlear nerve (VIII) pass through?

Answer 8

Internal Acoustic Meatus (IAM)

Question 9

What does the glossopharyngeal nerve IX pass through?

Answer 9

jugular foramen

Question 10

What does the vagus nerve (X) pass through?

Answer 10

jugular foramen

Question 11

What does the accessory nerve (XI) pass through?

Answer 11

jugular foramen

Question 12

What does the hypoglossal nerve (CN XII) pass through?

Answer 12

hypoglossal canals

Question 13

How many cranial nerves pass through the superior orbital fissure of the Sphenoid? Name them.

Answer 13

There are four:

• Oculomotor (III)
• Trochlear (IV)
• Trigeminal (V)*
• Abducens (VI)

In other words, cranial nerves 3, 4, 5*, & 6

*Note: The Trigeminal nerve splits into three divisions that pass through three different exits, the superior orbital fissure is only one of them.

Question 14

How many cranial nerves pass through the jugular foramen? Name them.

Answer 14

There are three:

• Glossopharyngeal (IX)
• Vagus Nerve (X)
• Accessory Nerve (XI)

In other words, cranial nerves 9, 10, & 11.

Question 15

How many cranial nerves pass through the internal acoustic meatus? Name them.

Answer 15

There are two:

• Facial Nerve (VII)
• Vestibulcochlear nerve (VIII)

In other words, Cranial Nerves 7 & 8

Note: The facial nerve pass through the internal acoust meatus AND facial canals as well

Question 16

Which cranial nerves pass through the hypoglossal canal? (Multiple Choice)

a) hypoglossal nerve
b) glossopharyngeal nerve
c) both the hypoglossal and glossopharyngeal nerves

Answer 16

just the glossophagynreal nerve

Question 17

In the image, what is #4? What is #10?

Answer 17

4 is the cribriform plate

Question 18

Which are the names of the following foramina:#12, #13, and #25?

Answer 18

12 - foramen rotundum

Tip: although in this particular photo the foramen ovale doesn’t look very “oval” shape, it probably is because the angle we’re looking at it. Remember the the foramen ovale is larger, and sits more posteriorly (behind) the foramen rotundum.

Question 19

Which is #20, 21, and 22 in the image below?

Answer 19

22 = internal acoustic meatus

Question 20

What is the name of the foramina the star/arrow is pointing at?

Answer 20

internal acoustic meatus

Tip: identify the larger and easier to identify jugular foramen. The internal acoustic meatus is smaller and sits above it.

In this different image below, the internal acoustic meatus is #22. And the jugular foramen is #21.

Bonus: The vestibulochoclear nerve (VIII) and part of the facial nerve (VII) pass through the internal acoustic meatus.

Question 21

What is the name of the formina highlighted in the image? What cranial nerve runs through it?

Answer 21

Optic Canal(s)

Optic nerve (II) runs through the optic canal(s)