Dural Sinuses

Question 1

How do the dural venous sinuses form and what do they contain?

Answer 1

Form when the periosteal and meningeal layers of the dura mater separate

Large, blood-filled spaces in the brain that replace the typical venous system

Question 2

Cranial Dural Septa

Answer 2

Extensions of meningeal layer of dura mater into cranial cavity–>support and stabilize brain

Falx cerebri, tentorium cerebelli, falx cerebelli, diaphragma sellae

Question 3

Falx cerebri

Answer 3

Largest sagittal fissue, separates 2 hemispheres of cerebrum

frontal bone–>crista galli–> internal occipital protuberance

hold superior and inferior sagittal sinuses

Question 4

Tentorium cerebelli

Answer 4

Crescent spetum that separates occipital lobes from cerebellum

Attaches to sphenoid, tempral, ocicpital and parietal bones

Question 5

Falx cerebelli

Answer 5

Vertical foldings inferior to tentorium in posterior cranial fossa

separates cerebellar hemispheres

Question 6

Diaphragma sellae

Answer 6

smallest dural septum suspended over sphenoid

covers pituitary gland

surrounds cavernous sinus

Question 7

Superior sagittal sinus

Answer 7

attached to falx cerebri

drains superficial cerebral veins and CSF down to confluence of sinuses

Question 8

Inferior sagittal sinus

Answer 8

Above corpus callosum, drains deep brain into straight sinus–> confluence of sinuses

Question 9

Transverse sinus

Answer 9

1st sinus coming out from confluence of sinuses in occipital region, converts to sigmoid sinus

Question 10

Sigmoid sinus

Answer 10

follows inferior cerebellum to drain directly into IJV

connects with superior and inferior petrol sinus near cavernous sinus

Question 11

Great cerebral vein

Answer 11

Drains inner brain next to inferior sagittal sinus

Question 12

General venous drainage of brain, head and neck

Answer 12

Superficial veins on top of cerebrum–> superior sagittal sinus

Great cerebral (deep) vein –> inferior sagittal sinus

Meet in confluence of sinuses–> transverse sinus–> sigmoid sinus–> IJV

Cavernous sinus to petrol sinuses–> IJV

Question 13

What are emissary veins?

Answer 13

go from scalp into bone

drain scalp to dural venous sinuses

Question 14

What are bridging veins?

Answer 14

in arachnoid space

drain blood from cerebral cortex to dural venous sinuses

Question 15

Subarachnoid hemorrhage

Answer 15

aneurysms of cerebral arteries that rupture and bleed into potential subarachnoid space

Question 16

Describe the general venous drainage of face via orbit and cavernous sinus.

Answer 16

Cavernous sinus drains ophthalmic and facial veins–> how infection can spread from face to meninges/brain

on either side of sella turcica: obtains blood from sphenoparietal sinus, middle cerebral vein, pterygoid plexus, ophthalmic and facial anastamoses

cavernous sinus feeds into superior and inferior petrol sinuses–> IJV alongside sigmoid sinus

Question 17

Cavernous sinus structures

Answer 17

Sits behind eye on either side of sella turcica (contacts sphenoid bone)

OTOM CAT go through sinus to get to eye

Oculomotor N
Trochlear N
Ophthalmic N
Maxillary N
--> lateral contents from superior to inferior

Internal carotid A
Abducens N
Trochlear N
—> medial to lateral

Question 18

What is the most commonly affected structure in the cavernous sinus?

Answer 18

Abducens nerve (CN VI)

sinus thrombosis squishes N d/t infection from danger zone of face (triangle from corners of mouth to bridge of nose)

Question 19

Cavernous sinus relationships with orbital N, drainage and sphenoid air sinuses

Answer 19

Sphenoid air sinuses on either side of nasal cavity
—>directly in front of pituitary gland

Cavernous sinus surrounds pituitary gland (covered by diaphragma sellae)

Optic nerve sits on top of sinus next to cerebral part of ICA (above/lateral to pituitary)

Question 20

Epidural hematoma

Answer 20

bleeding from middle meningeal artery (blow to pterion) in epidural space
b/t periosteal dura and bone (not an actual space–>only when something is wrong)

looks like lens on CT b/t it stops where the dura are tightly connected with the cranial sutures

lucid period after LOC, dramatically worsens

Question 21

Subdural hematoma

Answer 21

Rupture of bridging vein b/t dura and arachnoid mater d/t sudden acceleration or deceleration

Crescent on CT

Shaking baby syndrome
Older person with a/d
injury

Question 22

Subarachnoid hematoma

Answer 22

normally where CSF circulates

ruptured aneurysm of cerebral A (from ICA) b/t arachnoid and pia mater

spider web in center of brain on CT

WORST HEADACHE OF MY LIFE

postmenopausal, HTN

Question 23

What are middle meningeal arteries?

Answer 23

Branch off maxillary A (ECA)

supply meninges via foramen spinosum

Question 24

Innervation of meninges

Answer 24

CN V pattern for anterior aspect
   V3 on lateral anterior
   V2 b/t  and 3
   V1 from front middle 
      face back to 
      posterior/ occipital/ 
      brainstem region
--->  all meningeal 
        branches

C2 and C3 fibers (distributed by CN XII and CN X) innervate floor of posterior cranial fossa

Question 25

How does CSF drain?

Answer 25

via Arachnoid granulations that project into superior sagittal sinus if blood gets into meningeal spaces, it clogs these granules so they stop filtering CSF--> hydrocephaly