Dural Venous Sinuses Flashcards
What tissue type are the cranial meninges?
dense regular connective tissue
What are the three layers of cranial meninges (superficial to deep), including any sublayers?
Dura mater -periosteal layer -meningeal layer Arachnoid mater Pia mater
What forms the dural venous sinuses?
the periosteal and meningeal layers of the dura mater separate from eachother to form large blood-filled spaces
What forms the cranial dural septa?
the meningeal layer extends as flat partitions into the cranial cavity
What are the four main cranial dural septa?
Falx cerebri
Tentorium cerebelli
Falx cerebelli
Diaphragma sellae
List the progression of venous drainage of the face via the orbit and cavernous sinus.
Facial V. to Superior/Inferior Opthalmic V. to Cavernous Sinus to Superior/Inferior Petrosal Sinus to Transverse Sinus or Sigmoid Sinus Sigmoid Sinus becomes IJV
Describe the anatomical relationship between the cavernous sinus and the ICA.
The cavernous part of the internal carotid A. runs through the cavernous sinus
What nerves run through the cavernous sinus?
CN III - oculomotor N. CN IV - trochlear N. CN V1 - ophthalmic N. CN V2 - maxillary N. CN VI - abducens N.
Blue Box: Occlusion of Cerebral V’s and Dural Venous Sinuses
- facial V. to ophthalmic V’s. to cavernous sinus
- Cavernous Sinus Thrombosis:
- -infections in the orbit, nasal sinuses, or superior face
- -in thrombophlebitis of facial V., infected thrombus may extend into cavernous sinus
- -one sinus first, but spreads to other through the intercavernous sinus
- -acute meningitis
List the progression of the external carotid artery to the middle meningeal A.
external carotid A.
maxillary A.
middle meningeal A. (anterior/posterior branches)
List the progression of the internal carotid artery in the head.
internal carotid A.
- cervical part, petrous part, cavernous part, cerebral part
- Circle of Willis
-petrous part goes through the carotid canal
On what bone is the carotid canal?
temporal B.
What does the falx cerebri separate?
the two hemispheres of the cerebrum
What does the tentorium cerebelli separate?
cerebrum from the cerebellum
What does the falx cerebelli separate?
the two hemispheres of the cerebellum
What does the diaphragma sellae separate?
it acts as a “roof” above the pituitary gland, cavernous sinus and contents in the sella turcica area of the sphenoid B.
What is an epidural hematoma?
a bleed into the epidural space (b/w the skull and the dura mater
What is the clinical presentation of an epidural hematoma?
- lucid interval, followed by a sudden onset of serious neurological symptoms
- ruptured middle meningeal A.
- “lens-shaped” appearance on diagnostic imaging
- boundaries of “lens” against skull are probably suture lines
What is the clinical presentation of a subdural hemorrhage?
- seen in elderyly and in Shaken Baby Syndrome
- acceleration/deceleration injury
- chronic, progressive onset of neurological symptoms
- ruptured bridging V’s.
- “crescent-shaped” appearance on diagnostic imaging
What is the clinical presentation of a subarachnoid hemorrhage?
- ruptured cerebral A.’s
- blood pools at Circle of Willis in subarachnoid space
- aneurysm (buzz line: “worst headache of my life”)
- “spiderweb” on diagnostic imaging
- susceptible populations: postmenopausal women, pts with HTN, polycystic kidney disease and Ehler Danlos)
What nasal sinus sits directly inferior to the cavernous sinus?
sphenoid sinus
What structure sits in between the two cavernous sinuses?
pituitary gland
What structure lies superiorly to the cavernous sinus?
diaphragma sellae
In what space is the CSF?
subarachnoid space
What are the main functions of the CSF?
- buoyancy
- protection
- environmental stability
What makes the CSF?
ependymal cells in the choroid plexus in each ventricle
Where do ependymal cells originate from?
blood plasma
What are some biochemical properties of CSF?
- similar to blood plasma
- greater amounts of sodium, hydrogen and calcium
- less potassium
What structures drain CSF off the brain and into the dural venous sinuses?
arachnoid granulations
Clinical note: blood in the subarachnoid space damages the granulations (ex: in a subarachnoid hemorrhage)
What is hydrocephalus?
enlarged brain ventricles due to presence of excess CSF
