Dural Sinuses Flashcards
How do the dural venous sinuses form and what do they contain?
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
Cranial Dural Septa
Extensions of meningeal layer of dura mater into cranial cavity–>support and stabilize brain
Falx cerebri, tentorium cerebelli, falx cerebelli, diaphragma sellae
Falx cerebri
Largest sagittal fissue, separates 2 hemispheres of cerebrum
frontal bone–>crista galli–> internal occipital protuberance
hold superior and inferior sagittal sinuses
Tentorium cerebelli
Crescent spetum that separates occipital lobes from cerebellum
Attaches to sphenoid, tempral, ocicpital and parietal bones
Falx cerebelli
Vertical foldings inferior to tentorium in posterior cranial fossa
separates cerebellar hemispheres
Diaphragma sellae
smallest dural septum suspended over sphenoid
covers pituitary gland
surrounds cavernous sinus
Superior sagittal sinus
attached to falx cerebri
drains superficial cerebral veins and CSF down to confluence of sinuses
Inferior sagittal sinus
Above corpus callosum, drains deep brain into straight sinus–> confluence of sinuses
Transverse sinus
1st sinus coming out from confluence of sinuses in occipital region, converts to sigmoid sinus
Sigmoid sinus
follows inferior cerebellum to drain directly into IJV
connects with superior and inferior petrol sinus near cavernous sinus
Great cerebral vein
Drains inner brain next to inferior sagittal sinus
General venous drainage of brain, head and neck
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
What are emissary veins?
go from scalp into bone
drain scalp to dural venous sinuses
What are bridging veins?
in arachnoid space
drain blood from cerebral cortex to dural venous sinuses
Subarachnoid hemorrhage
aneurysms of cerebral arteries that rupture and bleed into potential subarachnoid space
Describe the general venous drainage of face via orbit and cavernous sinus.
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
Cavernous sinus structures
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
What is the most commonly affected structure in the cavernous sinus?
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)
Cavernous sinus relationships with orbital N, drainage and sphenoid air sinuses
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)
Epidural hematoma
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
Subdural hematoma
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
Subarachnoid hematoma
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
What are middle meningeal arteries?
Branch off maxillary A (ECA)
supply meninges via foramen spinosum
Innervation of meninges
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
How does CSF drain?
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
