Station 1: Dura & meninges

Question 1

Where does the falx cerebri (dural reflection) lie?

Answer 1

Between cerebral hemispheres

Question 2

Where does the falx cerebelli lie?

Answer 2

Between cerebellar hemispheres

Question 3

Where does the tentorium cerebelli lie?

Answer 3

Separates cerebellum from inferior portion of the occipital lobes

Question 4

Which parts of the brain are adjacent to the falx, tentorial notch and the foramen magnum?

Answer 4

Falx - midline of the brain
Tentorial notch - midbrain
Foramen magnum - medulla

Question 5

What is the blood supply to the dura and periosteum? From where do these arteries branch?

Answer 5

Meningeal arteries -

external carotid artery -> maxillary artery -> middle meningeal artery

Question 6

What is the reason for the characteristic shape of an extradural haemorrhage?

Answer 6

Can’t cross suture lines

Question 7

Does EDH haematoma develop rapidly or gradually? Why?

Answer 7

Rapidly - artery bleed

Question 8

Are EDHs always arterial?

Answer 8

Yes

Question 9

What limits the spread of EDH?

Answer 9

Sutures of the skull

Question 10

What layers does an extradural hamorrhage occur?

Answer 10

Skull and endosteal layer of the dura

Question 11

What is the typical MOI and clinical presentation of an EDH? Any associated injuries?

Answer 11

Pterion fracture, head trauma

Lucid interval -> LOC

Question 12

How do EDH differ from a SDH?

Answer 12

Location:
Extradural space (skull/endosteal layer of dura) and subdural space (dura/arachnoid mater)

Shape:
Convex (EDH) v crescent (SDH)

MOI and age of patient:
Younger, trauma (EDH) v older, shearing force (SDH)

Usual source of bleeding:
Middle meningeal artery (EDH) v bridging veins (SDH)

Question 13

What lies immediately deep to the arachnoid layers?

Answer 13

Subarachnoid space which containsCSF

Question 14

What are the arachnoid villi and arachnoid granulations?

Answer 14

Arachnoid granulations are small projections of arachnoid mater (villi) into the dura to allow CSF to re-enter circulation via dural venous sinus

Normally pressure of CSF > pressure of venous system
So CSF flows through villi and granulations into the blood

Question 15

Where are the dural venous sinuses located?

Answer 15

Between the two layers of the dura mater (endosteal/meningeal layer)
They are responsible for venous vasculature of the cranium, draining into the internal jugular veins

Question 16

How are the dural venous sinuses pictured?

Answer 16

Angiography of the head - Xray with dye and fluoroscopy (camera) of arteries or veins

Question 17

All dural venous sinuses eventually drain into which vessel?

Answer 17

Internal jugular vein

Question 18

Through which foramen do the dural venous sinuses leave the skull?

Answer 18

Jugular foramen

Question 19

Which structures pass through the cavernous sinus?

Answer 19

Internal carotid artery
CN III (oculomotor)
CN IV (trochlear)
CN V1 (opthalmic of trigeminal)
CN V2 (maxillary of trigeminal)
CN VI (abducens)

Question 20

What is cavernous sinus syndrome? What can cause it? What are symptoms of cavernous sinus syndrome?

Answer 20

Caused by:

• (bacterial) infection -> cavernous sinus thrombosis
• tumour (mets, nasopharyngeal, meningioma, pituitary)
• aneurysm of intracavernous carotid artery

Causing compression of the nerves:
CN III, IV, VI (resulting in opthalmoplegia - paralysis of all eye movements)
CN V1 (resulting in opthalmic sensory loss)
CN V2 (resulting in maxillary sensory loss)

Question 21

What are the symptoms of a complete lesion of cavernous sinus?

Answer 21

• Total opthalmoplegia, fixed, dilated pupil
• Sensory loss of opthalmic/maxillary divisions
• Horner’s syndrome (involvement of carotid ocular sympathethics):
  1. miosis (constricted)
  2. partial ptosis (droopy)
  3. anhydrosis (decreased sweaty)

Question 22

How does a traumatic dural venous sinus thrombosis (DVST) develop as a result of trauma. With which injury type are they most commonly associated?

Answer 22

Skull fracture/head trauma extending to a dural venous sinus.