Anatomical Spaces of the Head

Question 1

How does the thickness of the skull change from anterior to posterior?

Answer 1

The skull is thinner anteriorly and thicker posteriorly.

Question 2

In which plane does the tentorium cerebelli lie?

List the divisions of the cranial vault created by the tentorium cerebelli.

Answer 2

• The tentorium cerebelli lies in the horizontal / axial plane.
• It therefore divides the cranial vault into supratentorial and infratentorial compartments.

Question 3

Why is the periosteal / endosteal layer of dura mater not considered true dura mater?

What is the other layer of dura mater?

Answer 3

• Because the periosteal / endosteal layer of dura mater is a continuation of the periosteal layer of the bone of the skull.
• The other layer of dura mater is the meningeal layer of dura mater.

Question 4

List the attachments of the tentorium cerebelli.

Answer 4

• At its midline, it is attached to the falx cerebri. This attachment contains the straight sinus.
• Anteriorly, it attaches to the anterior clinoid processes of the sphenoid bone. This attachment forms the lateral part of the cavernous sinuses.
• Anterolaterally, it attaches to the superior border of the petrous part of the temporal bone, and extends further anteriorly to attach to the posterior clinoid processes. These attachments contain the superior petrosal sinus.
• Posterolaterally, it attaches to the transverse sulci of the occipital bone and internal occipital protuberance. These attachments contain the transverse sinus.

Question 5

Which structure separates the supratentorial compartments into left and right divisions?

Answer 5

The falx cerebri divides the supratentorial compartment into left and right divisions.

Question 6

What is the tentorial notch?

Answer 6

The opening created by the free anterior margin of the tentorium cerebelli through which the brainstem passes.

Question 7

List 3 extracranial spaces.

Answer 7

1 - Temporal fossa.

2 - Infratemporal fossa.

3 - Pterygopalatine fossa.

• These spaces are continuous (there are other spaces in the head but this lecture doesn’t mention them).

Question 8

List the borders of the temporal fossa.

Answer 8

• Superoposteriorly: Superior temporal line.
• Inferiorly: Zygomatic arch.
• Anteriorly: Frontal process of the zygomatic bone and zygomatic process of the frontal bone.
• Medially: Temporal, frontal, parietal and sphenoid bones (the temporal fossa contains the pterion).
• Laterally: Temporal fascia.

Question 9

Which muscle is contained within the temporal fossa?

Answer 9

Temporalis.

Question 10

Which vessel is contained within the temporal fossa?

Bifurcation of which vessel gives rise to this artery?

What is the other branch that arises from this bifurcation?

Answer 10

• Superficial temporal artery.
• This arises from the bifurcation of the external carotid artery.
• The other branch of the external carotid artery is the maxillary artery.

Question 11

From which vessel is the middle meningeal artery derived?

Answer 11

The middle meningeal artery is a branch of the maxillary artery.

Question 12

List the nerves contained within the temporal fossa.

Answer 12

1 - Mandibular branch of CN V.

2 - Anterior and posterior branches of the deep temporal nerve.

3 - Auriculotemporal nerve.

4 - Zygomaticotemporal nerve.

5 - Temporal branches of the facial nerve.

Question 13

List the borders of the infratemporal fossa.

Answer 13

• Superiorly: Infratemporal surface of the greater wing of the sphenoid bone.
• Inferiorly: Alveolar border of the maxilla.
• Medially: Lateral pterygoid plate of the sphenoid bone.

Question 14

List 5 foramina that open into the infratemporal fossa.

Answer 14

1 - Foramen ovale.

2 - Foramen spinosum.

3 - Alveolar canal.

4 - Inferior orbital fissure.

5 - Pterygomaxillary fissure.

• Make sure you can identify these on a diagram.

Question 15

List 7 nerves contained within the infratemporal fossa.

Answer 15

1 - Mandibular branch of CN V.

2 - Inferior alveolar nerve.

3 - Buccal nerve.

4 - Lingual nerve.

5 - Auriculotemporal nerve.

6 - Chorda tympani.

7 - Otic ganglion.

Question 16

List the muscles contained within the infratemporal fossa.

Answer 16

1 - Lower part of the temporalis muscle.

2 - Lower part of the medial and lateral pterygoid muscles.

Question 17

List the arteries contained within the infratemporal fossa.

Answer 17

1 - Maxillary artery.

2 - Middle meningeal artery.

Question 18

List the veins contained within the infratemporal fossa.

Answer 18

1 - Maxillary vein.

2 - Middle meningeal vein.

3 - Pterygoid plexus.

Question 19

Which nerve gives rise to the mandibular nerve?

Answer 19

The trigeminal nerve.

Question 20

List the structures that pass through the foramen ovale.

Answer 20

1 - Mandibular nerve.

2 - Accessory meningeal artery.

3 - Lesser petrosal nerve.

4 - An emissary vein connecting the cavernous sinus with the pterygoid plexus.

Question 21

List the structures that pass through the foramen spinosum.

Answer 21

1 - Middle meningeal artery.

2 - Middle meningeal vein.

3 - Meningeal branch of the mandibular nerve.

Question 22

What is an emissary vein?

Answer 22

A vein connecting the intracranial venous sinuses with the extracranial veins.

Question 23

Which nerve gives rise to the petrosal nerve?

Answer 23

The glossopharyngeal nerve.

Question 24

What is the function of the yawning reflex?

Answer 24

It brings about contractions of the pterygoid and masseter muscles, which act as a musculovenous pump to empty the venous blood of the pterygoid venous plexus.

Question 25

Which space is the intervening space between the neurocranium and viscerocranium?

Answer 25

The pterygopalatine fossa.

Question 26

What is the shape of the pterygopalatine fossa?

Answer 26

The pterygopalatine fossa has the shape of an inverted pyramid.

Question 27

List the bones that contribute to the ocular orbit.

Answer 27

1 - Frontal bone.

2 - Maxillary bone.

3 - Zygomatic bone.

4 - Sphenoid bone.

5 - Lacrimal bone.

6 - Ethmoid bone.

7 - Palatine bone.

Question 28

What is the sphenopalatine foramen?

Answer 28

The foramen that allows communication between the pterygopalatine fossa and the nasal cavity.

Question 29

What is the foramen rotundum?

List the structures that pass through it.

Answer 29

• The foramen that allows communication between the pterygopalatine fossa and the middle cranial fossa.
• The maxillary nerve passes through it.

Question 30

List the boundaries of the pterygopalatine fossa.

Answer 30

• Anteriorly: Posterior surface of maxilla.
• Posteriorly: Pterygoid process of the sphenoid bone.
• Medially: Perpendicular plate of the palatine bone.
• Laterally: Pterygomaxillary fissure.

Question 31

List the structures that communicate with the pterygopalatine fossa.

List the structures through which the pterygopalatine fossa communicates with these structures.

Answer 31

1 - Infratemporal fossa via the pterygomaxillary fissure.

2 - Middle cranial fossa via the foramen rotundum.

3 - Nasal cavity via the sphenopalatine foramen.

4 - Orbital cavity via the inferior orbital fissure.

5 - Palate via the palatine canal.

6 - Nasopharynx via the pharyngeal and pterygoid canals.