Meninges and Dural Venous Sinuses

Question 1

What are the 2 layers of the dura mater? Which is continuous with the dura mater of the spinal cord, and which is continuous with the periosteum on outside of skull?

Answer 1

Endosteal layer
Meningeal layer (dura mater proper)

Endosteal layer is continuous with periosteum on outside of skull through the foramina of the skull
Meningeal layer (dura mater proper) is continuous with the spinal cord

Question 2

What are the 4 dural septa (or infoldings) which separate regions of brain from each other?

Answer 2

Falx cerebri
Tentorium cerebelli
Falx cerebelli
Diaphragma sellae

Question 3

What attaches the falx cerebri anterior and posteriorly, as well as inferiorly?

Answer 3

Connected anteriorly to the inner surface of the skull from the frontal crest and the crista galli.
Connected posteriorly to the internal occipital protuberance
Inferiorly blends with the tentorium cerebelli

Question 4

What is the gap anteriorly in the tentorium cerebelli? What passes through here?

Answer 4

Called the tentorial notch for passage of midbrain

Question 5

What partially separates the cerebellar hemispheres?

Answer 5

The falx cerebelli

Question 6

What forms the roof of the sella turcica?

Answer 6

The diaphragma sellae; contains a small opening in center to allow passage of the pituitary

Question 7

What are the 6 major venous sinuses?

Answer 7

1. Superior sagittal sinus
2. Inferior sagittal sinus
3. Straight sinus
4. Transverse sinuses
5. Sigmoid sinuses
6. Cavernous sinuses

Question 8

What venous sinuses meet at the confluens of the sinuses?

Answer 8

Superior, sagittal, straight, occipital, and transverse

Question 9

Where does the superior sagittal sinus begin anteriorly and end posteriorly?

Answer 9

Begins anteriorly at the foramen cecum and ends posteriorly at the confluens of the sinuses near internal occipital protuberance

Question 10

Which sinus does the inferior sagittal sinus continue as after union with ____ vein?

Answer 10

The inferior sagittal sinus continues as the straight sinus after union with the great cerebral vein of Galen

Question 11

What sinus drains the confluens of the sinuses?

Answer 11

The transverse sinuses drain the confluens of the sinuses

Question 12

What sinus is a direct continuation of the transverse sinus? What does that sinus continue as?

Answer 12

Sigmoid sinus, continues as the internal jugular vein

Question 13

From which veins/sinuses do the cavernous sinuses receive blood from? Where do they drain to?

Answer 13

Receive blood from:

• Superior and inferior ophthalmic veins
• Sphenoparietal sinuses
• Cerebral veins

Drain to:

• superior and inferior petrosal sinuses
• Pterygoid venous plexus

Question 14

What arteries supply the dura?

Answer 14

The middle meningeal artery is the main blood supply (is a branch of the maxillary artery of the external carotid artery

Question 15

What provides innervation for the anterior cranial fossa?

Answer 15

Meningeal branches of the anterior ethmoidal nerve from the ophthalmic nerve (V1) supply floor and anterior parts of falx cerebri
Tentorial branch supplies the tentorium cerebelli and posterior part of falx cerebri

Question 16

What provides innervation for the middle cranial fossa?

Answer 16

Supplied medially by meningeal branches of the maxillary nerve (V2)
Supplied laterally by the meningeal branch of the mandibular nerve (V3) (follows distribution of the middle meningeal artery)

Question 17

What provides innervation for the posterior cranial fossa?

Answer 17

Supplied by meningeal branches of the first 3 cervical nerves

Question 18

What types of fibers do meningeal nerve branches that supply the dura carry?

Answer 18

They carry sensory neurons (e.g. with headaches, result of these sensory fibers)
Also carry postganglionic sympathetic fibers from superior cervical ganglion

Question 19

What results if there is infection in any part of the cavernous sinus?

Answer 19

Because there are no valves** in any of these sinuses, an infection in any of the regions that run through the cavernous sinus can spread to the cavernous sinus and elsewhere, causing thrombosis and meningitis (50% mortality)

Question 20

If this part of the side of the head is struck, what artery may be severed, and what does this result in?

Answer 20

If the pterion region of the head is struck, the middle meningeal artery may be severed, causing an epidural hematoma.
So an epidural is arterial blood*

Question 21

What causes a subdural hematoma?

Answer 21

Tearing of the superior cerebral veins at the point of entrance to the superior sagittal sinus. May be caused by a blow to the front of back of the head. Blood accumulates in space between dura and arachnoid membrane

Question 22

What causes a subarachnoid hemorrhage?

Answer 22

Leakage of (usually) arterial blood into subarachnoid space e.g. when there is a rupture or leakage of an aneurysm in the circle of Willis