HS2-8 Cranial Cavity

Question 1

The cranial cavity is subdivided into what three cranial fossae?

Answer 1

anterior cranial fossa (anterior to lesser wing of sphenoid)

middle cranial fossa (lesser wing of sphenoid to petrous part of temporal bone)

posterior cranial fossa (posterior to petrous part of temporal bone)

Question 2

What are the two layers of the cranial dura mater?

Answer 2

external layer (attached to bone)

internal layer (forms dural reflections)

Question 3

What are the subdivisions of the cranial cavity formed by the dura mater?

Answer 3

falx cerebri

tentorium cerebelli

falx cerebelli

diaphragma sellae

Question 4

What is the falx cerebri?

Answer 4

rigid partition between the cerebral hemispheres

Question 5

What is the tentorium cerebelli?

Answer 5

rigid partition that separates posterior and middle cranial fossae

Question 6

What is the falx cerebelli?

Answer 6

structure that partially separates the cerebellar hemispheres

Question 7

What is the diaphragma sellae?

Answer 7

structure that forms roof over hypophyseal fossa

Question 8

What structure is found between the two layers of dural reflections?

Answer 8

venous sinuses

Question 9

What are the eight primary venous sinuses found in the cranial cavity?

Answer 9

superior sagittal

inferior sagittal

transverse

sigmoid

straight

superior petrosal

inferior petrosal

cavernous

Question 10

The sigmoid sinuses drain into

Answer 10

the internal jugular veins

Question 11

The inferior petrosal sinuses drain

Answer 11

the cavernous sinus into the jugular foramen

Question 12

Label the following diagram.

Answer 12

Question 13

How is the subarachnoid space of the cranial cavity continuous with the subarachnoid space of the spinal cord?

Answer 13

continuous via foramen magnum

Question 14

Where is CSF formed in the cranial cavity?

Answer 14

formed in choroid plexuses of lateral, 3rd, and 4th ventricles of brain

Question 15

Describe the relationship between CSF and arachnoid granulations.

Answer 15

CSF is partially absorbed by arachnoid granulations in dural sinuses, especially superior sagittal sinus

Question 16

Nearly all venous drainage from the brain is conducted through the dural venous sinuses into the internal jugular vein. What are three collateral pathways of venous drainage from the brain?

Answer 16

ophthalmic veins (cavernous sinus to orbit to facial vein)

unnamed veins (cavernous sinus to pterygoid plexus to deep facial vein)

emissary veins (dural sinuses to diploë of cranial roof)

Question 17

How do the vertebral arteries enter the cranial cavity?

Answer 17

enter posterior cranial fossa through foramen magnum

Question 18

What happens to the vertebral arteries after they enter the cranial cavity via the posterior cranial fossa/foramen magnum?

Answer 18

vertebral arteries join to form basilar artery

Question 19

How do the internal carotid arteries enter the cranial cavity?

Answer 19

enter via carotid canal

Question 20

What do the internal carotid arteries do after entering the cranial cavity?

Answer 20

gives off branches that contribute to the cerebral arterial circle

Question 21

What are the three cerebral arteries that provide the blood supply to the cortex and deeper parts of the cerebrum?

Answer 21

anterior cerebral artery

middle cerebral artery

posterior cerebral artery

Question 22

What is the primary arterial supply to the meninges?

Answer 22

middle meningeal artery

Question 23

The middle meningeal artery is a branch of

Answer 23

the maxillary artery

Question 24

How does the middle meningeal artery enter the cranial cavity?

Answer 24

enters middle cranial fossa through foramen spinosum

Question 25

Describe the volume composition of the cranial cavity.

Answer 25

brain tissue + interstitial fluid = 80% CSF = 10% vascular compartment = 10%

Question 26

What is a secondary brain injury?

Answer 26

movement of brain within cranial cavity that leads to tearing/rupture of blood vessels

Question 27

List three types of secondary brain injuries.

Answer 27

epidural bleeding subdural bleeding subarachnoid bleeding

Question 28

What is epidural bleeding?

Answer 28

bleeding between bone of skull and outer layer of dura

Question 29

What causes epidural bleeding?

Answer 29

rupture of meningeal artery, often the middle meningeal artery at pterion

Question 30

What is subdural bleeding?

Answer 30

bleeding between inner layer of dura and arachnoid

Question 31

What causes subdural bleeding?

Answer 31

rupture of bridging vein, which connects cerebral vein with dural sinus

Question 32

What is subarachnoid bleeding?

Answer 32

bleeding into the subarachnoid space

Question 33

What causes subarachnoid bleeding?

Answer 33

rupture of branch of a cerebral artery

Question 34

What is the relationship between the size of the vasculature of the brain and brain injuries?

Answer 34

increase in size of brain vasculature will set up pressure gradients within cranial cavity that can shift brain tissue

Question 35

What are four general features of secondary brain injuries?

Answer 35

damage occurs some time after primary injury symptoms due to reduced brain and nerve activity symptoms develop gradually damage is treatable and reversible

Question 36

What are four specific features of secondary brain injuries?

Answer 36

gradual changes in behavior severe headache changes in respiration/BP/HR changes in cranial nerve function

Question 37

What happens in a tentorial herniation?

Answer 37

oculomotor nerve is pressed against tentorial incisure

Question 38

What is the result of a tentorial herniation? (3)

Answer 38

_results in:_ dilation of pupil on same side ptosis (drooping) of eyelid on same side eyeball turned laterally

Question 39

What is the primary difference between the dura mater found in the cranial cavity and the dura mater found in the spinal cord?

Answer 39

dura mater in cranial cavity has _two_ layers

Question 40

Between which layers of the meninges is CSF found?

Answer 40

between arachnoid mater and pia mater

Question 41

What are the two layers of the dural reflections?

Answer 41

periosteal meningeal

Question 42

Draw a diagram of venous sinus flow in the cranial cavity.

Answer 42

Question 43

Vertebral arteries are a branch of

Answer 43

the subclavian artery

Question 44

The anterior and middle cerebral arteries are derived from

Answer 44

the internal carotid artery

Question 45

The posterior cerebral artery is derived from the

Answer 45

basilar artery

Question 46

A rupture of the middle meningeal artery eventually results in

Answer 46

an epidural hematoma