Cranial Meninges, Dural Infoldings, and Dural Venous Sinuses

Question 1

Where do cranial meninges lie?

Answer 1

Deep to the cranium

Question 2

What are functions of the cranial meninges?

Answer 2

Protect the brain
Form supporting framework for vasculature and venous sinuses
Enclose the cerebrospinal fluid filled subarachnoid space

Question 3

Where is CSF formed?

Answer 3

Choroid plexuses of ventricles of the brain

Question 4

How does CSF travel?

Answer 4

Leaves the ventricular system and enters the subarachnoid space, where it cushions and nourishes the brain

Question 5

What is the role of the pia mater?

Answer 5

Attachment site for fibers of arachnoid mater

Question 6

What comprises the leptomeninx?

Answer 6

Arachnoid and pia

Question 7

What is the dura mater? What is another name for it?

Answer 7

Thick, dense, bilaminar membrane

Pachymeninx

Question 8

What are the two layers of dura mater?

Answer 8

Outer periosteal layer

Inner meningeal layer

Question 9

What roles do the dural infoldings play?

Answer 9

Compartmentalize cranial cavity

Support parts of the brain

Question 10

Where are the four dural infoldings?

Answer 10

Falx Cerebri
Tentorium Cerebelli
Falx Cerebelli
Diaphragma Sellae

Question 11

Where does Falx Cerebri lie?

Answer 11

Lies in longitudinal cerebral fissure

Separates the left and right cerebral hemispheres

Question 12

Where does the Tentorium Cerebelli lie?

Answer 12

Separates the occipital lobes of cerebrum from cerebellum

Divides cranial cavity into supratentorial and infratentorial compartments

Question 13

Where does the Falx Cerebelli lie?

Answer 13

Lies inferior to tentorium cerebelli, in posterior aspect of posterior cranial fossa

Partially separates the cerebellar hemispheres

Question 14

Where does the Diaphragma Sellae lie?

Answer 14

Horizontal shelf of meningeal dura mater - suspended between the clinoid processes, forming the ‘roof of the sella turcica’ that covers the pituitary gland

Question 15

Which bony landmarks are associated with the falx cerebri anteriorly?

Answer 15

Frontal crest of frontal bone and crista galli of ethmoid bone

Question 16

Which bony landmarks are associated with the falx cerebri posteriorly?

Answer 16

Internal aspect of occipital protuberance

Question 17

Which bony landmarks are associated wtih tentorium cerebelli?

Answer 17

Clinoid processes of sphenoid bone
Petrous part of temporal bone
Parietal bones
Occipital bone

Question 18

What are dural venous sinuses?

Answer 18

Dural venous sinuses are endothelial-lined spaces, located within the dura, between the periosteal and meningeal dural layers

Principle venous channels of brain; veins from brain’s surface empty into dural venous sinuses to internal jugular veins

Question 19

What are arachnoid granulations?

Answer 19

Outward bulges of dura mater

Prolongations of arachnoid mater that protrude through meningeal layer of dura into dural venous sinuses

Question 20

What is the role of arachnoid granulations?

Answer 20

Transfer CSF to venous system

Question 21

Where is the superior sagittal sinus? Where does it end?

Answer 21

Lies in superior border of falx cerebri

Begins at crista galli; ends near internal occipital protuberance at confluence of sinuses

Question 22

Where is the inferior sagittal sinus? Where does it end?

Answer 22

Lies in inferior border of falx cerebri

Ends in straight sinus

Question 23

Where is the straight sinus? Where does it end?

Answer 23

Runs along the line of attachment of the falx cerebri and tentorium cerebelli

Joins confluence of sinuses

Question 24

Where is the occipital sinus? Where does it end?

Answer 24

Lies in posterior border of falx cerebelli

Ends superiorly at confluence of sinuses

Question 25

Where do the transverse sinuses run?

Answer 25

Run laterally from confluence of sinuses in posterior margin of tentorium cerebelli

Continuous with sigmoid sinus

Question 26

Where do the sigmoid sinuses run?

Answer 26

Continuation of transverse sinus

S-shaped course

After passing through jugular foramina, continue as internal jugular veins

Question 27

Where is the cavernous sinus located?

Answer 27

Located bilaterally on sides of sella turcica on body of sphenoid

Question 28

Where does the confluence of sinuses receive venous blood from?

Answer 28

Superior sagittal sinus
Occipital sinus
Straight sinus

Question 29

Which arteries supply blood to the brain?

Answer 29

Internal carotid arteries

Vertebral arteries

Question 30

Describe the path of the internal carotid arteries

Answer 30

Arise in the neck from common carotid arteries

Ascend vertically in the neck to the cranial base

Pass through the external opening of the carotid canal and the internal opening of the carotid canal - within petrous portion fo temporal bone

Question 31

What are the 4 parts of the internal carotid artery?

Answer 31

Cervical part

Petrous part (in carotid canal within petrous portion of temporal bone)

Cavernous part (S-shaped path in cavernous sinus)

Cerebral part (intradural)

Question 32

Describe the path of the internal carotid artery in the cavernous sinus?

Answer 32

ICA exits the petrous part of temporal bone and enters the cranial cavity

ICA ascends to posterior clinoid process

ICA passes anteriorly, along the lateral aspect of the body of the sphenoid bone

ICA curves upward on medial side of anterior clinoid process

ICA pierces dura mater; the cavernous part of the ICA ends and the cerebral part of the ICA begins

Question 33

Where are the vertebral arteries found?

Answer 33

Arise in the neck from subclavian arteries

Ascend vertically in neck, passing through transverse foramina of cervical vertebrae (C6 - C1)

Enter cranial cavity via foramen magnum

Left and right vertebral arteries meet at midline to form Basilar artery

Question 34

Which vessels does the basilar artery provide?

Answer 34

Posterior cerebral arteries
Branches to brainstem
Superior cerebellar artery
Anterior inferior cerebellar artery

Question 35

What is the role of the posterior communicating arteries?

Answer 35

Small communicating arteries that provide a link between posterior cerebral arteries and internal carotid arteries

Question 36

What branches do the internal carotid arteries provide?

Answer 36

Middle cerebral arteries

Anterior cerebral arteries

Question 37

What is the role of the anterior communicating artery?

Answer 37

Connects both anterior cerebral arteries