Dural venous sinuses and ventricular systems Flashcards
What are the dural venous sinuses?
endothelium lined spaces between the periosteal and meningeal layers of the dura mater
Where do the dural venous sinuses receive tributaries from?
- brain
- diploë of skull
- internal ear
- orbit
What are the dural partitions?
- Falx cerebri (runs along midline between hemisphere)
- Tentorium cerebelli (forms roof over cerebellum)
- Falx cerebelli (between hemispheres but more inferior)
- Diaphragma sellae
Which dural partition holds the superior sagittal sinus?
Falx cerebri - within the upper border
Where will the superior sagittal sinus drain to?
- confluence of sinuses
- which drains into right transverse sinus
What sinuses meet to form the confluence of sinuses?
- superior sagittal dinus
- straight sinus
- occipital
- transverse sinus
Where will the inferior sagittal sinus drain to?
straight sinus
- then into confluence of sinuses
- then into left transverse sinus
Which partition are the right and left transverse sinuses in?
Tentorium cerebelli
What do the right and left transverse sinuses become?
right and left sigmoid sinuses which will then become internal jugular vein
At what point do the sigmoid sinuses become the jugular veins?
Jugular foramen
Where are the superior petrosal sinuses located ?
within margin of tentorium cerebelli that’s attached to superior border of petrous part of temporal bone
Where are the inferior petrosal sinuses located ?
within groove between petrous part of temporal bone and occipital bone
Where does the superior petrosal sinuses carry blood between?
- from cavernous sinuses
- to junction between transverse and sigmoid sinuses
Where do the inferior petrosal sinuses carry blood between?
- from cavernous sinuses
- to transition point of sigmoid sinus into internal jugular vein
Where are the cavernous sinuses located?
- either side of sella turcica
- connected via intercavernous sinus
What is the danger triangle of the face?
- veins draining regions of danger triangle are tributaries of facial vein
- facial vein drain to cavernous sinuses via superior and inferior ophthalmic veins
- infection spreads from face into cranial cavity
What secretes CSF?
- choroidal epithelial cells of choroid plexus
- choroid plexus located within lateral, third and fourth ventricles
- majority formed within lateral ventricles
What is the function of the CSF?
- cushions brain within cranial cavity
- provides nutrients
- responsible for removal of waste products from brain
Through what duct does CSF enter 4th ventricle?
cerebral aqueduct
What are the ventricles that CSF flows through?
Lateral ventricle
Third ventricle
Cerebral aqueduct (connects 3rd and 4th ventricles)
fourth ventricle (anterior to cerebellum)
What connects the lateral ventricles and 3rd ventricle?
Inter-ventricular foramen
How does the CSF get from fourth ventricles to subarachnoid space?
lateral and median apetures
What are arachnoid granulations?
- prolongations of arachnoid mater
- protrude through dura mater
- open into dural venous sinuses to allow for resorption of CSF
What may the pathology be if there is an obstruction to flow of CSF within ventricular system?
tumours which will then lead to rise in fluid pressure causing hydrocephalus
Symptoms of hydrocephalus?
- headache
- unsteadiness
- mental
- impairment
How is hydrocephalus treated?
decompression of dilated ventricles may be achieved by inserting a peritoneal shunt
What is the function of the dural partitions?
restrict rotary displacement if brain
What partition holds the inferior sagittal sinus?
lower border of falx cerebri
Where do the cavernous sinuses receive tributaries from?
- superior and inferior opthalamic veins
- spheno-parietal sinuses (located along lesser wing of sphenoid bone)
