Cranial Fossa

Question 1

What are the foramen of the anterior cranial fossa?

Answer 1

• Anterior ethmoidal foramen (anterior ethmoidal vein, artery, and nerve)
• Posterior ethmoidal foramen (posterior ethmoidal vein, artery, and nerve)
• Foramina of cribriform plate (olfactory nerves - CN I)

Question 2

What are the major foramina of the middle cranial fossa?

Answer 2

• Superior orbital fissure
• Greater wing of sphenoid (foramen rotundum, ovale, and spinosum)
• Carotid canal and groove for carotid artery

Question 3

What does the superior orbital fissure of the middle cranial fossa contain?

Answer 3

• Oculomotor nerve (CN III)
• Trochlear nerve (CN IV)
• Ophthalmic division of Trigeminal nerve (CN V1)
• Abducens nerve (CN VI)
• Ophthalmic veins

Question 4

Which foramina does the greater wing of the sphenoid contain?

Answer 4

• Foramen rotundum (maxillary branch of Trigeminal nerve, CN V2)
• Foramen ovale (mandibular branch of Trigeminal nerve CN V3, lesser petrosal nerve)
• Foramen spinosum (middle meningeal artery and vein)

Question 5

What are the parts of the sphenoid bone?

Answer 5

• Lesser wings (form the posterior limit of the anterior fossa)
• Body (jugum- joins two lesser wings and two greater wings centrally, hollow)
• Greater wings
• Pterygoid process (consist of medial and lateral pterygoid plates)

Question 6

What does the superior orbital fissure separate?

Answer 6

The lesser wing (of sphenoid bone) superiorly from the greater wing inferiorly (it is one of the foramina of the middle cranial fossa).

Question 7

Where is the optic canal located and what does it contain?

Answer 7

It is located in the body of the sphenoid (goes from body into orbit). It carries the optic nerve (CN II) and ophthalmic artery.

Question 8

What does the prechiasmatic groove contain?

Answer 8

The optic chiasm

Question 9

What are the 3 components of the sella turcica?

Answer 9

• Tuberculum sella (anterior border)
• Hypophyseal fossa (houses pituitary gland)
• Dorsum sella (posterior border from which posterior clinoid processes project)

Question 10

A dura mater venous sinus located lateral to the body of the sphenoid bone.

Answer 10

cavernous sinus

Question 11

What are the important structures of the cavernous sinus?

Answer 11

• Internal carotid artery
• Oculomotor nerve (CN III)
• Trochlear nerve (CN IV)
• Ophthalmic division of trigem. (CN V1)
• Maxillary division of trigem. (V2)
• Abducens nerve (CN VI)

Question 12

What are the major features of the posterior cranial fossa?

Answer 12

The major features are sinus cavities, as the dural venous sinuses form distinct impressions in bones of the skull as they drain toward the jugular foramen.

• Inferior and superior petrosal sinuses
• Sigmoid sinus
• Transverse sinus
• Occipital sinus
• Confluence of sinuses

Question 13

What are the 5 major foramina located in the posterior cranial fossa?

Answer 13

• Internal auditory meatus
• Jugular foramen
• Foramen magnum
• Hypoglossal canal
• Condyloid canal

Question 14

What does the foramen magnum contain?

Answer 14

• Medulla and associated meninges
• Vertebral arteries
• Sp. accessory nerve

Question 15

What does the internal auditory meatus contain?

Answer 15

• Facial nerve (CN VII)
• Vestibulocochlear nerve (CN VIII)
• Labyrinthine artery

Question 16

What does the jugular foramen contain?

Answer 16

• Glossopharyngeal nerve (CN IX)
• Vagus nerve (CN X)
• Sp. accessory nerve (CN XI)
• Inferior petrosal and sigmoid sinuses
• Posterior meningeal artery

Question 17

What does the hypoglossal canal contain?

Answer 17

-Hypoglossal nerve (CN XII)

Question 18

What are some of the dural reflections discussed?

Answer 18

• Falx cerebri
• Falx cerebelli
• Tentorium cerebelli
• Diaphragm sellae (thin covering over pituitary gland that supports hypothalamus)

Question 19

Where is the carotid canal located and what does it allow for passage of?

Answer 19

• Located in the middle cranial fossa lateral to sella turcica
• Allows passage of internal carotid artery and sympathetic nerve plexus